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Assessment of genetic diversity, farmer participatory breeding, and sustainable conservation of Eastern African sweetpotato

germplasm (Grant No. 02-476)

Annual Report (1st April 2004 – 31st March 2005)

Simon T. Gichuki (Kenya Agricultural Research Institute)

Don La Bonte (Louisiana State University)

Kornel Burg (Austrian Research Centres, Seibersdorf)

Regina Kapinga (International Potato Centre)

Jeremiah C. Simon (Lake Zone Agriculture Research and Development Institute)

Sweetpotato is one of the most important staple food crops consumed throughout East Africa. Limiting factors to increased sweetpotato production include viruses, weevils, low yielding varieties, lack of planting materials and poor soils. This Collaborative Crop Research Programme project of the McKnight Foundation involves scientists of the Kenya Agricultural Research Institute, Louisiana State University, The International Potato Center, Austrian Research Centers-Seibersdorf and the Root and Tuber crops program of Tanzania. It aims at improving East African sweetpotato productivity and sustainability through collaborative and participatory research. This is a report of project activities for 2004-5. Germplasm collected earlier were maintained for further breeding purposes. A total of 401 accessions in Arusha, Tanzania are to be characterized. More than 500 accessions in Kenya have undergone morphological characterization. Response to viruses and molecular characterization is in progress. An additional 200 records and basic descriptor information has been added to the GIS database. Updating of the web-accessible sweetpotato accession database has continued and 2 versions are now available on the web site via www.viazivitamu.org. The studies of SNP sites of the four beta-carotene pathway specific genes continued. CIP and regional scientists continued to evaluate and disseminate high dry matter OFSP (OFSP). Kenya, Uganda, and Tanzania alongside other African countries participated in a regional GxE trial. Progress was also made with seed families introduced in Uganda and Kenya during 2004. Mr. Mwamburi Mcharo completed Ph.D training on discriminant analysis studies at LSU while Wambui Njuguna completed MSc. training. Douglas Miano continued his Ph.D research studies on plant viruses in Kenya while two MSc. students initiated their research studies. Several FFSs were conducted in Kenya and Tanzania. These involved variety evaluation in addition to post-harvest processing training. Several papers were submitted for publication and presented in workshops by project scientists. The collaborators held an annual review and planning meeting in Nairobi.

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Assessment of Genetic Diversity, Participatory Breeding, and Sustainable Conservation of East African Sweet Potato Germplasm 1. Introduction In East Africa, sweetpotato is one of the most important staple food crops consumed throughout the region by most people. It is one of the three most important root crops alongside cassava and potato. It plays a significant role not only as a food security crop but also as a potential commercial and nutrition crop. Sweetpotato is particularly important in the Lake Victoria basin, coastal lowlands, and the highlands regions. Current trends indicate an increase in acreage under sweetpotato production probably due to commercialization of the crop. However, there are limiting factors to increased sweetpotato production; these include sweetpotato virus diseases, weevils, low yielding traditional varieties, critical shortage of planting materials of superior varieties and poor soils. Farmers grow many sweetpotato varieties, mostly landraces. These differ between regions with evidence of extensive diversity of sweetpotato genetic resources in the region. Current production ranges between 5 - 13 tons ha-1 while the potential is 30 t ha-1. Previous lack of involvement of farmers who are beneficiaries has in the past led to non- adoption of those technologies. Therefore, there is need to evaluate and select varieties with the involvement of farmers for development of higher yielding, disease resistant / tolerant and pest resistant varieties that are also nutritionally rich in β-carotene a precursor for Vitamin A. This project funded by the Collaborative Crop Research Program (CCRP) of the McKnight Foundation was initiated in 2002. Project partners are the Kenya Agricultural Research Institute (KARI), Louisiana State University, and The International Potato Center (CIP), Austrian Research Centers-Seibersdorf and the Root and Tuber crops program of Tanzania. This project aims at improving East African sweetpotato productivity and sustainability through collaborative and participatory research on germplasm conservation, crop improvement, and development of technology for planting material production and post harvest value addition. This report focuses on the project activities during the period April 2004 to March 2005.

2. Participatory germplasm conservation, mananagement and

utilization 2.1. Morphological, Molecular and GIS Characterization of Kenyan Sweet Potato

Germplasm East Africa is the largest producer of sweet potato in Africa. The crop is said to have higher genetic diversity than other root crops such as cassava, yams, or cocoyams. The short tropical day lengths found in East Africa favors sweet potato flowering leading to hybridization and arising of new varieties. In addition, the nature of its dispersal and vegetative propagation has created a vast number of cultivated genotypes. Conservation of this germplasm is necessary

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for the improvement of agricultural production. Characterization of germplasm is the first step in establishing a core collection which promotes easier management of the genetic diversity. A total of 564 sweetpotato varieties were collected from different regions of Kenya (Nyanza, western, central and Eastern). These were morphologically characterized. Out of these 483 varieties were identified as unique while 61 had duplicates in the collection. A principle component analysis using the variance co-variance method showed that the shape of the central leaf lobe had the highest influence in discriminating between. Storage root shape had the lowest influence. From dendrogram generated using the UPGMA method all the varieties clustered as unique varieties within a genetic distance of 0.3 – 0.7. The bootstrap values ranged from 0 – 95 % while most of the values were below 50 %. There was no distinct clustering according to geographic location. Five ISSR primers that gave the highest variation were selected and used for fingerprinting. Primers differed in the ability to identify unique multiband phenotypes among the 22 sampled popular farmer’s varieties. None of the ISSR primers was able to discriminate between the 22 varieties. All the varieties clustered as unique varieties within a genetic distance of 0.1 to 0.6. Cheglina Mowar showed similarity to Ngorobu from a genetic distance of approximately 0.45. The bootstrap values ranged from 0 – 55 % but most were below 50 %. There was no distinct clustering with regard to geographical location; however two Tanzanian varieties Sinia and Budagalla clustered together from a genetic distance of approximately 0.3 at a bootstrap value of 19%. The locations of the sweetpotato collection a site were well recorded and coordinates (latitude and longitude) were assigned to the collections. These readings were used to generate a GIS map with DIVA-GIS. DIVA-GIS were used to carry out grid analysis on the mapped collection sites. It was also used to visualize the diversity of the shape of central leaf lobe descriptor in relation to collection points of sweet potato varieties and in molecular/diversity analysis of the sweet potato collections. Molecular distance and diversity analysis was carried out using Jaccard’s distance (J). It was also possible to search for varieties with specific morphological or agronomic characteristics. 2.2. Study of beta-carotene genes Two hundred and fifty offspring individuals of the Tanzania X Beauregard family were kindly provided by the North Carolina State University (Bryon Sosinski and Craig Yencho). All of the previously discovered SNP sites of the four beta-carotene pathway specific genes were tested as to whether they segregate within the family members. Geranyl diphosphate synthase (GGPP) This gene was identified using the (homology score 2e-26) original sequence SpEST455, the cDNA is 755bp long. GGPP gene was amplified using a single pair of primers (Geranyl_L640/Geranyl_U113). The total size of the PCR product was about 1760bp. The entire GGPP gene spans a total of 1921bp. 4 exons (147, 136, 168, and 312bp respectively) and 3 introns (409, 254, and 495bp respectively) were found. GGPP gene structure is presented in Figure 1. Fifty-seven putative SNP sites were found across the gene by comparing the two sweetpotato cultivars “Tanzania” and “Beauregard”. SNPs were found mostly in the intron area, for instance, 29 SNPs were found in intron 2, whereas only 9 SNPs

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were found in exon 2. The cSNPs sites studied yielded for synonymous substitutions, which do not change the protein structure. The gene contained a large number of single base INDELs at the 5’ end, which disturbed the sequencing of the gene. A total of 96 offspring samples were analyzed so far with 7 SNP markers selected for segregation analysis. Out of them 4 markers showed segregation pattern but two of them were distorted. Markers Gera.654.C, Gera.1581.A, and Gera.1674.A were slightly linked to each other, thus being located on the same chromosome. All simplex markers were coming from the ‘Tanzania’ parent. One duplex marker, coming from the ‘Beauregard’ parent, was also detected. Lycopene β-cyclase (LYC) The LYC gene was also amplified using degenerate primers and a partial sequence of approximately of 517bp was amplified. The same procedure to identify intron or exon sequences was applied. No intron sequence was found in the amplified part of the gene. 14 SNP sites occurred across the sequence with a frequency of 1 SNP every 27bp.. A total of 10 markers were selected for segregation analysis in the 192 offspring. Three showed distorted segregation ratios (markers not fit any ratio for any known inheritance pattern). The seven markers left could be separated into 3 simplex markers, and 4 double simplex markers groups. The simplex marker group was coming from the ‘Tanzania’ parent, and was all segregating together, thus representing one single allele. The double simplex markers could be divided into two independent groups of segregation. In this locus, 3 allelic forms could be resolved. Farnesyl diphosphate synthase (FPP) The FPP gene was amplified using degenerate primers. Only a partial sequence of the FPP gene with a PCR product size of 453bp was used for this study. The PCR product from the parents and later from the offspring was used as a template for sequencing. Unfortunately, no reference EST sequence of sweetpotato FPP was available for comparison, in order to identify if the PCR product was an exon sequence or intron part or a combination of both. To overcome this problem, the sweetpotato sequence obtained with our primer-pairs was translated into an aminoacid sequence and aligned with other FPP protein sequences obtained from the gene bank. As seen from the picture, two portions of the sweetpotato FPP gene showed a high similarity to the other sequences, but 3 fragments flanking these two matching sequences showing no homology were found. The first guess was that these 3 fragments were intron sequences. To prove this, the two matching fragments were transformed again into DNA sequence and this was aligned with a cDNA sequence of FPP from Arabidopsis thaliana. It was found that these two sequences aligned one after another the A. thaliana sequence, thereby suggesting the correct orientation of the PCR fragment relative to the cDNA. It could be revealed also that the partial sweetpotato FPP gene possess 3 introns and 2 exons of sizes 81 bp and 117bp respectively. A total of 10 SNP sites were found across the partial sweetpotato FPP gene (4 SNPs in exon regions and 6 in the intron area). The cSNPs studied yielded for synonymous substitutions, and therefore protein structure may not be affected. All these SNP sites were tested also in the offspring for segregation analysis in a total of 192 offspring samples. All markers were simplex and coming from the ‘Beauregard’ parent. All markers were completely linked. Therefore only one allele could be resolved. The linkage mapping of these selected genes will be done in collaboration with Jim Cervantes, Bryon Sosinski and Craig Yencho from NCSU who developed several AFLP markers for the Beauregard Tanzania mapping family.

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2.3. Germplasm database management using GIS Consultations between LSU and KARI were done in Nairobi between 28-29 October 2005 to assess the progress and documentation of the sweetpotato accession database. This meeting resulted in the addition of over 200 records to the database and the addition of basic descriptor information. Updating of the web-accessible sweetpotato accession database has continued and 2 versions are now available on the web site accessible via www.viazivitamu.org. The first version is a GIS-based viewer that allows spatial display of accession data. The second version is a tabular or flat-file format that features a searchable interface. This allows users to search for specific traits like variety name, skin, and flesh color. This version also includes images that are available for 75% of the records. The inclusion of images with each record enables users to view typical vegetative characteristics like leaf shape and growth habit along with the text-based descriptors. There are currently 326 records available on the accession database. A workshop was held in February 2005, Nairobi, Kenya, on advanced training of collaborators and regional scientists on the use of publicly available CIP-developed GIS software. There were 13 participants in this workshop. This workshop focused on using GIS tools for ecological niche modeling and developing decision support systems. 2.4. Sweet potato germplasm maintenance and conservation in Kenya and Tanzania The germplasm collected from the first two years of the project were maintained for further breeding purposes. A total of 401 accessions in Tanzania have been transferred to the national germplasm collection in Arusha for characterization planned for May 2005. More than 500 accessions in Kenya have been transferred to Kakamega and Kabete where they have undergone morphological characterization. Response to viruses, storage pathogens and molecular characterization is in progress. Several accessions have been lost due to virus infection. 2.5. Evaluation of widely grown local sweetpotato genotypes at Kakamega, Kenya Farmers in Kenya grow a wide range of sweetpotato varieties the bulk of which are local landraces. These have been selected over time from various sources including clonal introductions, new types resulting from mutation of the existing clones, and selection of chance seedlings. There probably exist among the farmers’ varieties a small number of clones, which would have a combination of superior characteristics, which would qualify them for official recommendation as varieties. Previous germplasm collection exercise in western Kenya showed that a few varieties were more popular and widely grown than the others. This study was initiated to identify among the popular varieties those that can perform well and be adapted by farmers in the mid-altitude upper midland agro-ecological zone of Kenya. Thirty-four widely grown local accessions were planted at KARI-Kakamega during the 2004 long rain seasons. The field plot design was a randomized complete block design with two replications. Each plot (3.6 x 4 m) consisted of four ridges at 100 cm row spacing and 30 cm between plants. Data were collected on vine weight, root yield and virus infection. Virus infection was scored using a scale of 1-5, where 1= no virus symptom and 5=severe virus symptoms including stunted plants. The trials were well maintained and plants harvested after 170 and 176 days after planting in 2003 and 2004, respectively.

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The mean storage root and foliage weights of sweetpotato accessions were higher in 2003 than in 2004. Some of the accessions, which gave high root yields in 2003, performed poorly in 2004. This was probably as a result of high virus infection registered in 2004. Accessions Nyathi odiewo, Wera, K/KA/2002/170, K/KA/2002/191, Nyatonge and K/KA/2002/173 gave high root yields in both seasons. The sweetpotato variety Mugande, which was included only in the second season, outyielded all entries except Nyathi odiewo. The best four varieties will be included in the next set of National Performance Trials (NPT) and on-farm validation trials in western Kenya in 2005.

2.6. Sweet potato Preliminary yield trial in Tanzania A total number of 69 local accessions were evaluated in Ukiriguru, but poor weather was resulted in low yields which could justify selection hence the trial was replanted. Five of the accessions had strong reactions to SPVD with a virus score of 3-4. 3. Farmer participatory breeding 3.1. Introduction of high dry matter high B-carotene clones from CIP-Lima, Peru During 2004, CIP worked with scientists from Kenya and Tanzania to disseminate high dry matter OFSP (OFSP) introduced clones in form of mini cuttings through the the plant quarantine station at Muguga, Kenya. Kizimbani Research Station in Zanzibar received at least 40 clones while Kibaha and Maruku research stations in the central and Lake Zone respectively in Tanzania received at least few clones. In Kenya, a few clones were distributed to KARI centres in Kakamega, Katumani and Mtwapa as part of a regional GxE trial. The materials distributed include the following CIP lines; 199004.2, 199005.11, 199015.14,199024.1,199024.2, 199026.1, 199027.3,199034.1,19962.1, 440203, 440443, Zapallo, Salyboro, Tainung 65, Jonathan, Jewel, Kandee, Centennial, Excel, Japon Tresmesino, TIB-4, W-151, Beauregard, Costanero, Resisto, NC-1560, TIS-83/0138, TIS-2534, VSP-4, Jewel, Julian, BP-SP-2, Nemanete, Tainung 64, SPK004, LA 10 SHU 44, NC 317, Camote Rosita, Tainung 15, Comensal, Maria Angola, and CN 144-59. The multiplication of these materials in several other African is in progress in preparation for adaptability studies.

Progress was also made with seed families (high dry matter & high B-carotene) introduced in Uganda and Kenya during 2004. In Kenya 20% selection rate for the clones was done and these were advanced for further observation and selection at Kakamega, Katumani, Kabete and Mtwapa Centres. In Uganda zero selection percentage of the clones was observed due to high virus pressure prevalence at Namulonge research station. However, about 10 clones (from the same seed batch) have been selected for further evaluation at Serere research station. This is possible because of low virus pressure prevalence at Serere station.

3.2. Sweetpotato breeding program at Kakamega, Kenya Seedling evaluation of high dry matter orange-fleshed sweetpotato genotypes A seedling trial consisting of 2100 genotypes from 19 families were planted at KARI-Kakamega in June 2004. The seedlings were planted on ridges spaced at 100 cm apart and 50

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cm between seedlings. Orange-fleshed sweetpotato variety SPK004 was planted at the end of every family to act as a check. The plots were harvested in November 2004 and 300 clones selected on the basis of root yield, dry matter content, and the intensity of root orange-colour. The selected clones were advanced to the clonal evaluation stage at KARI-Kakamega during the 2004/2005 short rain season. Screening of High Dry Matter Orange-fleshed Sweetpotato genotypes under low virus pressure conditions A total of 2290 seedlings from 40 families were planted at the Alupe sub-centre in July 2003 and 341 advanced to the clonal evaluation stage during the 2003/2004 short rain season. Eighty-eight clones were selected on the basis of high DM content, virus infection; root size and colour and advanced to PYT stage at Alupe sub-centre during 2004 long rains. The trial plot consisted of 15 cuttings planted on a single row-plot and replicated two times. The preliminary yield trial was harvested on 17th November 2004 and 30 clones selected for AYT evaluation in 2005. Planting material of the selected clones is under multiplication at Alupe in readiness for further evaluation during the 2005 long rain season. Advanced Yield Trial (AYT) of orange-fleshed sweetpotato varieties Twelve orange-fleshed sweetpotato varieties selected from the sweetpotato-breeding program at KARI-Kakamega, local accessions and introductions from the PRAPACE member countries were evaluated at KARI-Kakamega during the 2004 long rain season. The objective of the study was to identify orange-fleshed varieties suitable for production in western Kenya. Varieties were planted in a randomized block design with three replications. Each plot consisted of four ridges spaced at 100 cm apart. Cuttings were placed 30 cm from each other. Data were taken on storage root yield, vine weight, plant vigour and virus infection.

Storage root and vine production of the clones tested were low as a result of high infestation with sweetpotato virus disease. Root yields ranged between 0.2 to 24.3 tons/ha. Variety Nyathi odiewo had the highest yield although it has comparatively low ß- carotene levels (judging from the intensity of the orange colour). Jewel produced 14.4 tons/ha despite the high virus infection.

G x E high dry matter content orange-fleshed sweetpotato clones trial Eight high dry matter content orange-fleshed clones obtained from CIP Lima were tested at Kakamega and Mtwapa KARI-research centers during the 2004 crop season. These two locations represent contrasting agro-ecological zones: Kakamega (altitude: 1585 meters above the sea level, annual rainfall 1900 mm, mean temperature 20+ 220C) and Mtwapa (altitude: 15 m above the sea level, annual rainfall 1200 mm, temperature 24+ 260C). The soil at Kakamega is classified as humic nitosols while in Mtwapa the soil is orthic ferralsols. The experiments were set up at each location in a randomized complete block design with four replications. Each plot had four ridges, 6 m long with a spacing of 100 cm between ridges and 50 cm within rows. Each plot contained 60 plants. Fields were kept clean by regular hand weeding. Data were taken on plant vigour, virus infection, storage root yield, fresh weight of vines, dry matter content.

Mean total root yield of the clones ranged between 3.3 tons/ha in 199027.3 and 32.4 tons/ha in 199062.1. The best root yields were obtained from 199062.1, 199015.14, 199026.1 and 199004.2. The low root yield at this site could be attributed to high virus infection observed with all clones except SPK004 and 199062.1. The lowest yielding clone 199027.3 had the

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highest virus and alternaria score which also contributed to the poor growth vigour observed in the trial. The amount of vines produced by all clones except SPK004 was low. Clones 199024.2 and 199027.3 were affected by alternaria disease.

3.3. National Performance Trials of sweetpotato varieties at Kakamega and Alupe, Kenya

One of the major factors limiting sweetpotato production in Kenya is lack of varieties suitable for different sweetpotato producing agro-ecologies. Studies have shown that sweetpotato yield, especially of cultivars with high yielding potential, is highly sensitive to environmental variations. Selections made at one breeding site may not necessarily be adapted in all sweetpotato-growing areas. There is therefore, a need to conduct multi-locational tests of the advanced clones in order to identify varieties targeting specific environments and uses. The objective of this study was to identify sweetpotato varieties suitable for production in different sweetpotato growing agro-ecologies of western Kenya. The final set of the national performance trial consisting of 13 common varieties and two promising local accessions were planted at Alupe sub-centre and KARI-Kakamega during the 2003 short rain and 2004 long rain season, respectively. The trials were established in a randomized block design with three replications. The cuttings were planted in ridged plots spaced at 100 cm between the ridges and 30 cm apart. Each plot consisted of four rows. Data were collected from the two middle rows on plant vigour using a 1-5 scale where, 1=very weak and 5=very vigorous growth, fresh weight of marketable and total roots, vine wt, and virus disease infection (1-5 scale) where 1=no virus symptoms and 5=severe virus symptoms and stunted growth.

Varieties 91/218, Mwavuli, 56668/03 and 389a-H-12 continued to do well at KARI-Kakamega. Mwavuli had the highest root weight followed by the local variety Nyathi Odiewo. Most of the varieties tested at the site had low virus infection despite the high rainfall received during the season. The varieties also had high vine production ranging from 19.1 to 73 tons/ha. Outstanding varieties will be tested in the on-farm trials under farmers’ management conditions during the 2005 long rain season.

3.4. Discriminant analysis studies Mwamburi Mcharo (Kenyan National) completed his Ph.D. program in horticulture in May 2005. Publications are listed in Section 5 for 2004-2005. The essence of his program was to validate through a series of publications the utility (proof of concept) of using multivariate statistical techniques to associate plant traits to molecular markers. Traditional trait-linked marker research has relied on trait variation within progeny populations of related ancestry. The difficulty in sweetpotato is that segregating progeny populations do not always contain sufficient numbers in desired classes. For example, it is nearly impossible to have sufficient numbers of plants resistant to the Sweet Potato Virus Disease (SPVD) in order to map. The techniques developed by Mcharo permit assemblage of a SPVD resistant group of plants to compare with a group of SPVD susceptible plants. SPVD resistance is a trait that would be far easier to screen via molecular markers versus traditional graft inoculations, particularly as we try to move resistance into high yielding orange flesh varieties. 3.5. Sweetpotato Virus disease studies Douglas Miano of KARI returned to Kenya from Louisiana Stated University in September 2005 to conduct research related to his dissertation, “Response of sweet potato to sweetpotato

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virus disease and identification of DNA markers linked to resistance to the sweet potato virus disease”. Sweetpotato virus disease (SPVD) is a serious threat to sweetpotato production in East Africa and the world over. The disease is a result of synergistic interaction between viruses. The current study aims to identify the presence of key viruses in East Africa, characterize the response of resistant materials to SPVD infection, and identify DNA markers for resistance to SPVD, and identify virus distribution patterns in field grown sweetpotato. Miano has refurbished several greenhouses at KARI Biotechnology Centre to conduct virology research, namely graft indexing. His efforts have re-invigorated others with expertise in virology to conduct such work.

Virus identification: Miano screened 300 accessions collected from throughout Kenya for sweetpotato viruses that have yet to be identified in Africa. Several accessions with symptoms consistent with Sweet Potato Leaf Curl Virus were graft inoculated to Ipomoea setosa (index host). The DNA from I. setosa leaves were extracted to test for the presence of this DNA virus. Plants with symptoms consistent with SPVG, were also tested to NCM ELISA after grafting onto I. setosa; tests were negative; however, a positive reaction was recorded in the first screen. More tests are underway. The use of I. setosa permits viruses present in low titre in sweetpotato to amplify in the susceptible inoculating stock to facilitate identification. All accessions tested were treated in this way. This represents a novel approach to sweetpotato virus identification work in Africa. Viruses can be at a low titre in sweetpotato plants and fail to give a positive NCM ELISA.

Plant virus distribution: Antidotal evidence suggests young, growing sections of sweetpotato are free of viruses. It is not known if the fresh growing points are actually free of viruses nor how far down on the vine they remain free of viruses. We would like to recommend to growers how far down on the vine they should cut plants for propagation purposes. An initial screen of 23 cultivars identified nine that behaved differently, i.e., viruses present in all or just some of the three vine sections (terminal, mid-section, or distal section). Each of the sections was graft inoculated onto I. setosa. The indicator plant was screened for five viruses (SPFMV, SPCSV, SPMMV, SPVG and IVMV). SPFMV, SPCSV and SPMMV are the three main viruses identified in Kenya. The first replicated study is currently underway, and will be followed by second replication of the study. Initial results indicate that there is more variability in distribution of different viruses in cultivars which showed no virus symptoms in the field as compared to highly susceptible cultivars.

Sweet Potato Virus Disease: Many cultivars are putatively resistant to Sweet Potato Virus Disease. Many harbor the virus and become tolerant; later, during stressful conditions, symptoms are expressed. Many may also escape infection because of vector preferences. The object is to graft inoculate 100 putatively resistant varieties with SPVD (sweetpotato feathery mottle virus and sweetpotato chlorotic stunt virus) to determine symptom expression. These varieties will then be grafted to I. setosa for virus indexing. The intent is to identify cultivars that possess a resistant reaction. The most promising are destined for the U.S. to use in studies to characterize the behavior of the viruses in a resistant cultivar. Approximately 15-30 in each category will be shipped to the U.S. Some will originate from the International Potato Center collection.

Miano spent three months (June-August 2004) at LSU conducting research. His activities were on testing the possibility of using real-time PCR on the movement of SPFMV and SPCSV in single and dual infections; and on the effect of infection of three potyviruses (SPVG, IVMV and SPFMV) on eleven sweetpotato cultivars. One of the mechanisms of

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resistance of plants to virus infection is by limiting the virus movement from the point of infection to other plant parts. Real time PCR has the advantage in that it is possible to measure the concentrations of virus particles in a particular section of the plant, and thus compare titre levels at different distances from point of inoculation. Cultivar Porto Rico was used in this study, and was artificially inoculated with the two viruses separately or in combination. The two viruses were detected from different sections, though at low concentrations. Real time PCR will be used for further studies using susceptible and resistant cultivars.

To understand the mechanisms of resistance of plants to virus infection, it is important to

know how a susceptible one reacts. A few cultivars are reported to be susceptible to SPFMV.

However, none has been observed to show clear symptoms of infection by SPFMV alone.

The study was to establish how eleven cultivars reported to be susceptible to SPFMV reacts

to infection by either of the potyviruses or the combination of the three. The titre levels were

determined using real time-PCR. The virus concentrations were fairly low in all the 11

cultivars used. However, SPVG concentrations were relatively higher than SPFMV and

IVMV.

4. Farmer participatory planting material production, management and

conservation

4.1. Participatory Evaluation of sweet potato in FFS in Tanzania Fifteen sweet potato varieties were evaluated in two Farmers Field Schools of Igulumuki and Buhongwa in the lake zone, Tanzania. These trials were planted in March 2003/2004 during the long rainfall. A long drought adversely affected the varieties with poor yield results. Three varieties had virus scores above 2.5 while one was totally (Zapallo) susceptible. Varietie Kakamega, Carrot Dar, and Misalaba and Zapallo, were selected by farmers. The most important criteria used by farmers to select these varieties included Taste, drought tolerance and early bulking ability despite low rainfall. These three varieties are currently being multiplied at the centre. At Kibaha in the Eastern zone, Tanzania the entire germplasm collection was evaluated and 14 accessions selected based on yield, dry matter contents and reaction to pests and diseases. Pests and diseases scores ranged between 1-3 while yields of 1.8 to 13.7t/ha were achieved. Dry matter content ranged from 32-41% with most varieties being above 30% 4.2. Training of FFS members in Tanzania Training was conducted in all established FFS in the two Zones of Tanzania, the aim of these training is to equip FFS members with all in formation regarding sweet potato production. A total of 132 farmers were trained. The training was done in a group of farmers and farmers were assigned tasks of doing follow up using AESA. It is expected that farmer groups who

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received the training will act, as trainers of other farmers and therefore more farmers will benefit from this training. The training covered all aspects of Sweet potato agronomy, plant protection, post-harvest handling/processing/product development and rapid multiplication. 4.3. Participatory variety evaluation with FFSs in Eastern Kenya The root and tuber crops program in KARI-Katumani with the support of McKnight East Africa Sweetpotato Project has been testing sweetpotato clones developed by CIP and other agencies within the region for wide adaptability in diverse agro-ecological zones. These clones are high yielding, bulk early and are tolerant to drought, pests, and diseases. To assess the acceptability of these clones to farmers, two farmer field schools were initiated in Kathiani and Kangundo divisions of Machakos district. Two field schools were formed to advance the orange-fleshed sweetpotato technology. These schools were located in Kangundo and Kathiani divisions of Machakos district namely, Syuuni Farmer Field School-Kathiani and Kavilinguni Farmer Field School-Kangundo. Ground working and village immersions were done during the month of March 2004. This was accomplished by extension and research facilitators previously trained on the FFS Approach. The sequence of activities involved included a transect walk across the farms of the farmers represented followed by a meeting with all the farmers. In addition to the research and extension personnel, this initial meeting was also attended by the area chief to represent the provincial administration. At this time, potential sites for the schools were chosen. Registration of the school followed in a subsequent visit, April 6, 2004 for Kavilinguni and May 6, 2005 for Syuuni FFS. During this day, the election of the host farmer, identification of stakeholders and crop and livestock technologies were done. This exercise was attended by the by more than 60 farmers (majority being men). Launching of the FFS was done on April 24, 2004 Kavilinguni and May 13, 2005 for Syuuni FFS. During the launching, school leadership, norms, and FFS concepts, objectives and goals were discussed. Four working groups were formed and office bearers selected. Each group was assigned the responsibility to handle one variety from planting to harvesting. A daily attendance roster was also initiated and rules and regulations to govern the school spelt out. This exercise was attended by up to 25 farmers (20 men and 5 women). A curriculum was developed which included, land preparation, planting material selection, planting, variety characteristics, and AESA data collection. The groups met every 2 weeks for classes to carry out the management practices and collect data throughout the FFS duration. The data in the field schools was taken using the Agro-Ecosystem Analysis (AESA) system. This is a systematic field observation of plants, their environment, and the interactions. It is the study of plant morphology and agronomy, pests and their natural enemies. The data collected at this school included plant establishment, the growth rate and yield. Four improved sweetpotato clones, Zapallo, Kemb10, SPK 004, and Japonese were introduced in the schools. Munyilya, the most common local farmers’ landrace was also included as a local check. Each variety was planted in a 4m x 6m plot at a spacing of 75cm x 50cm. The daily attendance dropped between the 4th and 6th week to a low of 15 farmers per session. But this stabilized to around 20 farmers per session after the 7th week. This drop may have been caused either by the tough rules and norms that the farmers set or drought that was prevailing in the area with some of the farmers preferring to spending more time in search of food rather than attending the field school. It is also interesting to note that significantly more

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men than women attended the farmer field schools. It is not easy to explain this disparity in gender attendance as traditionally, the sweetpotato is regarded as a woman’s crop. Women having been involved in sweetpotato production for a long time may have been of the view that they had nothing new to learn from the FFS. From the farmers’ results, varieties Zapallo and SPK004 had the highest vine length, while Japonese and Munyilya had less foliar growth. But Munyilya and Japoness had the least number of dried up plants indicating that restricted vine growth might be a drought tolerance mechanism. Low growth rates during drought would mean low transpiration rates and hence reduced moisture loss. Variety Zapallo on the other hand may have had a better stay-green ability than the other varieties making it have a higher growth rate and higher number of plants surviving than the others. The variety KEMB 10 was ranked highly in terms of acceptability by consumers but had the second lowest yield. The local variety, Munyilya, which is white, had the lowest rankings for both yield and acceptability. This was expected considering that the school was promoting the use of Orange fleshed Sweetpotato Varieties. Zapallo and SPK004 had the highest average yield and acceptability. These were therefore recommended for multiplication and wider distribution.

4.4. On-farm evaluation of sweetpotato varieties in Western Kenya Ten farmers in Kabras division assessed two local accessions ‘Nyathi’, and ‘Nyandere’, and an orange-fleshed sweetpotato variety Ejumla under their farm conditions. The trial was conducted during the 2003/2004 short rain season. Varieties were planted on plots 6 x 6 m with each farmer used as a replicate. Sweetpotato variety SPK004 was used as a check. Farmers multiplied planting material in one of the farmer’s field before distributing cuttings to participating farmers. At harvest, root samples were cooked and tasted by farmers. Ranking of the varieties was done based on yield, root taste, and ability of varieties to withstand drought. The results showed that all varieties had acceptable taste. Variety ‘Nyathi’ was ranked first by all farmers followed by SPK004. The variety Ejumla though liked because of its deep orange colour, was susceptible to both virus disease and drought. The demand for planting material was very high and attempts are being made to involve the existing farmer groups for seed multiplication.

4.5. Participatory Evaluation of OFSP using the FFS Approach in Ndeiya, Central Kenya.

Ndeiya division of Kiambu district in Central Kenya is classified as semi-arid, with an erratic rainfall of between 500-700 mm/year in 2 rainfall seasons. Most households in the area depend on relief food from the government and other donors. In the past sweetpotato had been grown by many farmers in the area as a food security crop. Several factors led to its decline thereafter including: migration to other areas, new enterprises, moles, porcupines, sweetpotato weevils, and changing eating habits. The McKnight Sweetpotato Project sought to intervene in the food insecurity problem of the area by participatory evaluation of the sweetpotato varieties, germplasm conservation, post-harvest processing and income generation using the farmer Field School approach.

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Two FFSs were established in Ndeiya and Thigio sublocations of Kiambu District with a total of 51 farmers. Participatory Technology Demonstration (PTD) plots in a simple design was established with 8 sweetpotato varieties (Japonese, Zapallo, Kemb-10, Ex-simba, Spk-004, Enaironi, Mugande, Bungoma) and a local check (Muibai) for each school. Each variety was planted in 4 row-plots at a spacing of 75 x 30 cm on a plot size of 5.2 x 2.25 m using the ridge-planting and flat-planting methods. Harvesting of each variety was done at maturity followed by post- harvest evaluation for each variety using the culinary tests (taste-tests). Using materials from the PTDs the farmers were involved in hands-on processing, product development and evaluation of the sweetpotato products, at different crop growth stages. Again culinary tests were used to evaluate the different products. The farmers also ranked the products into household use and income generation. There was no major difference in attendance between the men and the women. The FFS went through a sweetpotato curriculum, which had both specific and special topics. The specific topics had direct relation to sweetpotato while the special topics were selected by the farmer’s based on their needs. Nderu- Mirithu FFS had a duration of 8 months while Thigio-Gichungo FFS took 10 months. Both longer than anticipated due dry conditions during the growing season.

The AESA observations indicated that Zapallo, Japonese and Bungoma had the poorest establishment. Method of planting (ridge or flat) did not influence establishment. Ridging resulted in longer vines and more sprouting than flat-planting. The ridge-planted materials performed better than flat-planting. The farmers attributed this to better water and soil conservation in ridging. Variety SPK 004 had a high reaction to pest and disease in the early crop growth stage but recovered over time. Japonese and Zapallo were most affected by drought but matured early followed by KSP 20, Kemb-10, Ex-simba, Muibai (local check) and Bungoma. Enaironi formed very few storage roots. Varieties Enaironi and Muibai (local check) had the highest vegetative growth and ground coverage indicating suitability as a fodder for soil conservation. Through the AESA the farmers were able to identify different pests that attack the sweetpotato crop and also make decisions on how to control them. The farmers prepared and applied some of the indigenous technical knowledge to address some of the pests that were observed. This included preparation and application of some natural pesticides to control the aphids, moles, weevils, and porcupines. This included the following: ♦ Spraying the crop with a mixture of Mexican- marigold extracts to control the aphids. ♦ Sprinkling of the kitchen ashes around the based of the plant control the weevils. ♦ Placing of stinging nettle plant into the hole of a mole. The mole due to the sting will

wrestle with the plant until it dies out of exhaustion. ♦ Sprinkling of disinfectant (Kerol) around the crop field. The animal does not stand the

smell of disinfectant. ♦ Creating barriers around the farm to keeps off the porcupine. The animal does not like

climbing due to its short legs hence it will go around the plot, get tired and giving up. Generally, the performance of some of the ITK was good but further work need to be done to assess their levels of performance and quantify the same.

There was no notable difference between in total yield between the ridge and flat planting. But generally all the varieties performed better in flat planting which is the common practice

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in the area. Japonese gave the highest yields best followed by KSP 20. The large storage roots can be marketed or used as flesh roots while the non-marketable roots can be processed for use at home/market and/or used for development of value added products.

4.6. Collaboration with Africa Now in variety evaluation This research was carried out by Africa Now (AN) in collaboration with the International Potato Center (CIP) and Kenya Agriculture Research Institute (KARI) Kakamega. Currently, AN is undertaking a project known as the Natural Resource Management (NARM). The objective of the project is to enhance household food security and increase incomes in targeted rural areas of Western and Nyanza provinces through better management of land and diversification of crops. Among other interventions the project is promoting Orange Fleshed Sweet Potato (OFSP) as a food security crop. The project is involved in the production, processing, and utilization for enhanced household nutrition and income from the sale of fresh and processed tubers. The organization (AN) collaborates with KARI Kakamega and CIP as technology providers. It also collaborates with the government, CBOs and other NGOs as service providers in the western region of Kenya to scale up the production, processing, and utilization of the OFSP. Through NARM, over 300 small-scale farmers have planted OFSP varieties on their farms. They have also attended several field days where OFSP utilization demos have been done by KARI trained groups. Six trial sites were established in the year 2003 for 12 varieties. Vines were supplied by CIP to four different farmers in different locations. The 12 varieties are still on farmers' fields but their identification has been lost and needs to be re-identified. In the year 2004, four other trial sites were established. They had a total of 20 new varieties supplied by CIP in collaboration with KARI Kakamega. Farmers evaluated these varieties and selected those they were interested in multiplying and adopting. The second part of the project (training in utilization and processing) is not reported here.

4.7. Virus Cleaning of OFSP local varieties collected from Kenya, Uganda and Tanzania

CIP continued with cleaning activities for the local OFSP varieties at PQS Muguga Kenya. During 2004, Tanzania and Uganda submitted their dirty OFSP local collections to Muguga. Three additional varieties (Kabuchenche, Tomola and Ex-Kanyigo) from the Lake zone of Tanzania have been collected and are yet to be submitted for cleaning. The current status of the cleaning activities is as shown in the table 1. Table 1. Local popular orange-fleshed varieties collected in different countries Country Name(s) of varieties Status of clean-up

to-date Projection(s) Remarks

Zambezi, Mayai, Pipi, Ex-chanika, Ukerewe and Carrot-C

Raising plantlets in the tissue culture lab

Rapid multiplication of plantlets in the screen house to start by mid-Dec.

Tanzania

Kabuchenche, Tomola and Ex-Kanyigo

Not yet submitted To submitted in May, 2005

Uganda Abuket I, Abuket II and Gweri,

Plants in the thermotherapy room

Transfer meri-stems to growth media by end of November

Kenya 566682/02, K118, K135, Sponge, Nyathi odiewo, Mwavuli, Plot 134,

Rapid multiplication of plantlets in the

Planting materials ready for distribution by end Jan, 2005

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Nyaguta, Nyatanga, 566682/03, Mwavuli

screen house

At the same time CIP continued to maintain a collection of over 200 pathogen free clones; 9 NASPOT clone series and 20 high B-carotene high DM clones in in-vitro form at Plant Quarantine Station (PQS) at Muguga. The purpose is to conserve all the germplasm of importance for both immediate and future uses. Routine indexing to confirm the health status of clones was done twice during the year by using Elisa virus detection kit and grafting test clones on Ipomoea setosa. 4.8. Production of Clean Plant Material in Tanzania Introduction and making available clean sweet potato planting materials of improved sweet potato varieties is the perquisite to realizing high root yield. Accessibility of these materials by farmers is dependent on multiplication and distribution of clean planting materials. Supply of planting materials from research has not met the demand by farmers because sweet potato like other vegetative plant has low multiplication ratio. The objective of basic seed production was to establish sweet potato seed nurseries to act as source of nucleus planting materials for secondary multiplication by farmers, NGOs and CBOs. During the 2004/2005 seasons, in anticipation of food shortages due to drought, the Tanzania government directed that each household had to grow drought tolerant crops particularly cassava, sweet potato and sorghum. The Lake zone Agricultural Research and Development Institute (LZARDI) responded by multiplying and distributing sweet potato planting materials to farmers for secondary multiplication. This activity was done in collaboration with district councils in areas where the sweet potato project is operating (McKnight project) the areas included Misungwi, Meatu, Sengerema and partially Kwimba districts. Varieties that were multiplied and distributed from sweet potato seed nurseries at LZARDI, Ukiriguru were Simama, Jitihada, Vumilia, Mavuno and Sinia, which are officially released varieties. Other varieties Kakamega, Carrot Dar and ,Zapallo, these are some of the orange fleshed sweet potato varieties that have been tested on farm for acceptability studies. These varieties have been tested in on-farm between 20021 to 2004 have been acceptable by farmers. All the planting materials that were distributed were further multiplied in communal nurseries in order to increase the number of beneficiaries. A total of 225,450 vines were distributed. 4.9. Degeneration of sweetpotato planting material studies at Kakamega, Kenya Degeneration studies with pathogen tested planting material have been going on at the centre since 2001. The present study compared the performance of sweetpotato varieties planted with pathogen tested (PT), 2nd generation (G2), 4th generation (G4) and 6th generation (G6) planting material. Two sweetpotato varieties Kemb 10 and Mugande were used in the study. The treatments were laid out in a randomized complete block design with three replications. Cuttings for planting G2 to G6 plots were taken from the field at random. Plants were spaced at 100 cm between rows and 30 cm between plants. Data were taken on virus infection, vine and storage root yield.

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Results showed that age of planting material had no effect on vine production but influenced virus score and storage root yield. The virus score was highest with the G6 planting material. Plants established with the PT planting material gave significantly higher storage root yield than those established with the G6 cuttings.

4.10. Seed multiplication activities at Kakamega, Kenya The tissue culture derived planting material of sweetpotato varieties Mugande, Kemb 10, Mogamba, Karat, Dar-es-salaam, and Zapallo are under multiplication in the screenhouse at KARI-Kakamega. Seed multiplication nurseries were established near the screenhouse during the season. The centre has also established a 0.5 ha of sweetpotato seed multiplication plot. It was observed that farmers conserve their planting materials in various ways:

i) Most farmers practice in-situ germplasm conservation method whereby the materials are planted under the shade of a tree, banana or behind the house.

ii) Farmers also consider exchange of planting materials between farmers as one method of germplasm conservation

5. Post Harvest Value addition

5.1. Post harvest evaluation with farmers in Tanzania Farmers indicated that though orange varieties are sweeter than white-fleshed varieties, they have low dry matter contents. They recommended improvement of the varieties dry matter content to make them more acceptable.

PPrroocceessssiinngg aanndd UUttiilliizzaattiioonn ••SSwweeeett ppoottaattoo iiss hhiigghhllyy ppeerriisshhaabbllee;; aass ssuucchh rroooottss ccaannnnoott kkeeeepp ffoorr mmoorree tthhaann 55 ddaayyss aafftteerr hhaarrvveesstt.. IInn ggrroouunndd ssttoorraaggee oonn tthhee ootthheerr hhaanndd iiss lliimmiitteedd bbyy ppeesstt iinnffeessttaattiioonn.. IInn vviieeww ooff tthheessee pprroobblleemmss pprroocceessssiinngg ooff sswweeeett ppoottaattoo iinnttoo mmoorree ssttaabbllee pprroodduuccttss bbeeccoommeess iinneevviittaabbllee.. •In the Lake zone of Tanzania sweet potato is processed into two local products namely Michembe and Matobolwa, in the production of michembe roots are withered, cut into slices using a local knife and dried while for matobolwa the roots are boiled, sliced and then dried. These two processes ensure continued supply of sweet potato for home consumption/sale for a period of 5-8 months. However the use of the local knife in the preparation of these products is laborious and time consuming. •Farmers in three locations tested and evaluated an improved sweet potato slicer against the use of the local knife in the preparation of a processed product called michembe. •Two kg of fresh roots was subjected to the two chipping equipments and chipping time recorded and chipping rate calculated. Duration of drying time was also recorded. A mean chipping output of 220kg/hr was possible with the improved slicer whereas with the local knife it was only 36kg/hr. Slices from the improved slicer dried in 2 days compared to 3 days of slices using the knife.TThhee ffaasstt ddrryyiinngg rraattee wwaass ccoonnttrriibbuutteedd bbyy tthhiinnnneessss aanndd uunniiffoorrmmiittyy ooff sslliicceess ffrroomm iimmpprroovveedd sslliicceerr.. IItt wwaass ccoonncclluuddeedd tthhaatt ssiimmppllee pprroocceessssiinngg mmaacchhiinneess ccaann iimmpprroovvee tthhee eeffffiicciieennccyy ooff ttrraaddiittiioonnaall pprroocceessssiinngg ooff sswweeeett ppoottaattoo iinnttoo ttrraaddiittiioonnaall pprroodduuccttss ((mmiicchheemmbbee)) aanndd rreedduuccee wwoorrkkllooaadd ffoorr wwoommeenn aanndd cchhiillddrreenn..

Product development

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FFaarrmmeerrss iinn tthhee tthhrreeee llooccaattiioonnss rreecceeiivveedd ttrraaiinniinngg oonn tthhee pprreeppaarraattiioonn ooff sseeccoonnddaarryy pprroodduuccttss ffrroomm bbootthh wwhhiittee aanndd oorraannggee--fflleesshheedd sswweeeett ppoottaattoo,, tthhee ttrraaiinniinngg ooff sswweeeett ppoottaattoo pprroodduuccttss iinncclluuddeedd ccaakkeess,, cchhaappaattttiiss,, ddoonnaattss,, kkaaiimmaattii aanndd bbuunnss.. GGrroouuppss ooff rraannddoommllyy sseelleecctteedd ffaarrmmeerrss ffrroomm tthhee tthhrreeee ssiitteess eevvaalluuaatteedd tthhee pprroodduuccttss ffoorr aacccceeppttaabbiilliittyy.. TThhee eevvaalluuaattiioonn ccrriitteerriiaa uusseedd wweerree:: pprroodduucctt ttaassttee,, sshhaappee,, ccoolloouurr aanndd oovveerraallll pprroodduucctt pprreeffeerreennccee.. OOvveerraallll aacccceeppttaabbiilliittyy aasssseessssmmeenntt bbyy ffaarrmmeerrss aanndd ccoonnssuummeerrss iinnddiiccaatteedd tthhaatt,, KKaaiimmaattii--oorraannggee wwaass rraannkkeedd ffiirrsstt ffoolllloowweedd bbyy KKaaiimmaattii--wwhhiittee,, AAnnddaazzii--oorraannggee,, CCaakkee-- oorraannggee,, CCaakkee--wwhhiittee,, ddoouugghhnnuutt--oorraannggee aanndd CCaakkee ––wwhhiittee iinn tthhaatt oorrddeerr iinn SSeennggeerreemmaa ssiittee.. WWhhiillee iinn MMiissuunnggwwii ssiittee,, ddoouugghhnnuutt--oorraannggee rraannkkeedd ffiirrsstt ffoolllloowweedd bbyy KKaaiimmaattii--oorraannggee,, AAnnddaazzii--wwhhiittee,, aanndd CCaakkee ––oorraannggee.. IItt wwaass ccoonncclluuddeedd tthhaatt tthere is need to promote and link new and high value sweet potato products through involving processors, market participants, policy makers and other sweet potato stakeholders. In addition moorree rreecciippeess ffoorr sswweeeett ppoottaattoo pprroodduuccttss nnoott aass yyeett iinnttrroodduucceedd eegg jjuuiicceess rreeqquuiirreedd..

5.2. Processing and Product development in Central Kenya Farmers in 3 areas of central Kenya (Ndeiya – Kiambu district, Mukurueini – Nyeri district and Kieni – Embu district) were trained through hands-on demonstrations in making of dry chips and leaves by sun drying. They also made various sweetpotato products using different cooking methods. A total of eleven products were developed with farmers. Varieties SPK 004 and Japonese were the most preferred among the orange-fleshed varieties for various uses. Variety SPK 004 was preferred for vegetable stew (Relish), mashed food (mshenye/Irio), chapati, samosa and biscuits. Japonese and Zapallo were the best for juices, vegetable stew (Relish), onion bites, chinchin (stripes), samosa, biscuits chapati, and vegetable stew while Ex-simba was the most preferred as a vegetable.

The farmers ranked the products based on use, either for household use and /or income generation. All the products except chinchin, crackies, and biscuits ranked high for household use while chips, porridge, pancakes and dried vegetable scored the least as marketable products.

5.3. More OFSP products come in the local markets: New products form OFSP were produced in Kenya: 3 new OFSP based products (Food flavours, soap and jams) were tested with several groups in . R Western region and Nairobi. These are currently being promoted for commercialization. Rural women in local kiosks and trading centers are marketing these. Farmers and processors mainly women have earned incomes for household cores 6. Capacity Building

6.1. Popularising the OFSP in East Africa by CIP

a) Two open campaigns were held in Tanzania under the objective of popularizing the OFSP. Farmers demonstrated to fellow farmers various technologies on sweetpotato production and utilization, including multiplication techniques for planting materials.

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b) An international exposure visit was organized for sweetpotato farmers, traders and processors from three countries, Kenya, Uganda, and Tanzania to Italy for the World Meeting of Food Communities. Participants used the opportunity to share experiences on various aspects with the rest of the world. They developed friends and business contacts. c) Sensitization with Send a Cow. Send a Cow is a church based initiative that works to improve the livelihoods of communities through promotion of zero grazing diary cattle. The organization recently realized that sweetpotato was one of the major crops grown by the same farmers keeping cattle under zero grazing systems. The objective of the sensitization was to create awareness among the farmers the various benefits of sweetpotato and the way it integrates within the farming system. d) Radio and video programs were aired on various local radio and television stations where either farmers or other technical collaborators presented and answered many issues regarding production and utilization of sweetpotato. For example the local minister of agriculture at the district aired 2 programs on radio Veritas in Soroti sensitizing farmers. Central broadcasting station in Kampala, Uganda also hosted a farmer in its studios more than twice during 2004. e) Calendars for the year 2005 showing sweetpotato production and utilization technologies have been printed. An estimated 5000 copies will be distributed in Uganda, Kenya and Tanzania targeting mostly the farmers, extension and health personnel as well as local leaders. This builds on the experiences from the calendar that was published in 2004 in Uganda, which created a lot of awareness that resulted into increased demand for sweetpotato technologies. f) At least 15 newspaper articles on the production and utilization of OFSP have been published with journalists and other partners in different media in different countries (Uganda at least 10 articles; Tanzania at least 4 articles and Kenya at least 3 articles). 6.2. Harmonisation of sweetpotato breeding methodologies workshop A weeklong training course was held in Kampala – Uganda between June 20th and 27th. Of the thirty-five participants (breeders and agronomists) from 13 countries in SSA that attended the course, 15 participants were drawn from Uganda, Kenya, and Tanzania. CIP’s sweetpotato breeders and a virologist from SSA and Lima organized and backstopped the training. The main objectives were to take inventory of different breeding approaches, methods, and protocols used by different partners in the sub-Saharan Africa region; to discuss and harmonize approaches, methods and protocols for sweetpotato breeding; and in the region; and to acquaint the partners with available statistical and biometric tools emphasizing on participatory research methodologies. Also conducted was a field attachment for senior technicians and new scientists in sweetpotato breeding research at Namulonge to gain a practical knowledge and skills on breeding methods, data collection and seed multiplication techniques. 6.3. Exchange visit for regional breeders to Kibaha and Zanzibar As a follow up of the breeding methods short course, a working visit was held for breeders from Kenya, Uganda and Tanzania during which different trials at and around Kibaha and

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Kizimbani research stations all in Tanzania, were harvested. A total of 16 scientists participated in the visit. The visit gave yet another opportunity for breeders to interact on experimentation methodologies and protocols directly in the field. Experiences were shared on the type and techniques of data collection especially from on farm trials. 6.4. Participation in workshops and seminars Several project scientists from all the partners participated in various workshops and seminars. The highlight was Insternational Society of Tropical Rootcrops (ISTRC) conference in Mombasa between October 31 and November 5th. Several poster and oral presentations were made by the project scientists (see abstracts in Annex 1). One farmer from Ngamalenga Women Group in Kisumu was sponsored by the project to demonstrate sweetpotato products in the workshop. 6.5. Farmer educational tour of sweetpotato growing areas in Kenya A group of 16 farmer, 6 extension officers from Central, and Eastern Kenya made an educational tour of the sweetpotato production systems in Western and South Western Kenya from 27th February to 4th March 2005. The team visited with NGOs, CBOs and farmers involved in the promotion of orange-fleshed sweetpotato for amelioration of Vitamin A malnutrition. The group also visited KARI’s drip irrigation and seed multiplication sweetpotato projects around the Nairobi area. They also had a chance to see how degradation of the environment can be reversed by visiting the Lare land reclamation project in Nakuru. 6.6. Training of PhD and MSc. students

• Mr. Douglas Miano continued this research work on sweetpotato viruses in Kenya. Douglas goes back to complete his Ph.D study program at Louisiana State University in August 2005. Progress on his work is reported elsewhere in this report.

• Ms. Wambui Njuguna completed her MSc. thesis research on the analysis of sweetpotato passport data using Geographical Information Systems (GIS) and Characterization with morphological and molecular Markers. A summary of her thesis research is presented elsewhere in this report.

• Mr. Johnson Kwach has completed the course work for his MSc. training program. He has initiated his thesis research. An abstract of his research study is presented in the abstract 1.

• Mrs. Theresia Ngendello has been registered at the Sokoine University of Agriculture in Tanzania for a post-harvest MSc. degree. She has completed her course work and is developing a research thesis proposal. Her MSc. study topic is ‘Evaluation of sweetpotato clones for farmers’ acceptability’. in Tanzania for an MSc. in Food technology.

7. Participation in Technology Transfer Activities 7.1. Technology Dissemination in Central Kenya Two Farmer field days were conducted by the two FFSs (Nderu-Mirithu and Thigio- Githigio FFS). The FFS members demonstrated and explained what they have learnt about

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sweetpotato production, management, processing and utilization (value addition). This provided an opportunity for the farmers to do farmer-to-farmer extension. A total of 100 farmers attended the Nderu-Mirithu FFS field while 50 farmers attended the Thigio- Gichungo FFS field day. Both fields were conducted on the FFS learning plots. The Nderu-Mirithu FFS participated in the Central Kenya Show in July 2004, where they displayed some the sweetpotato products that they had made in the FFS. 7.2. Completion of FFS – ICM field manual by CIP The field manual was not completed on schedule due to many critical changes proposed by the reviewers. Currently a final draft of the manual is under corrections and will be submitted for printing by the end of May 2005. An estimated 500 copies of the final copy will be distributed to partners in the region. The manual will serve as a reference tool for extensionists and farmers on different aspects of sweetpotato production and utilization. 7.3. Development of FFS manual in Tanzania The LKZARDI, Ukiriguru has developed a draft manual in local language (Kiswahili) on all aspects of sweet potato production and started using it in the established FFS. The aspects covered include land preparation, selection of planting materials, planting, field maintenance, identification of pests and diseases, pests and diseases control strategies, processing, and utilization which include product development. 8. Project Management Activities 8.1. Annual planning meeting held in Nairobi, Kenya- 14th- 19th February, 2005. The meeting was attended by all the projects key partners and collaborators. On the first day a plenary session was formerly opened by KARI’s Deputy Director in charge of Research and Technology, Dr E. A. Mukisira. The director urged the scientists to accelerate sweetpotato research particularly in value addition and marketing and expressed KARI’s commitment to improvement of the crop. This was followed by ten presentations on various aspects of the project. Each presentation was followed by a short discussion session. During the following three days the team divided into two parallel sessions. One team was involved in advanced GIS training led by Arthur Villordon of LSU. The second team of the virologists and the PIs held discussions around the PhD. Students thesis and then traveled to Western and South Western Kenya to review the projects activities with CBOs and assess the extent of the sweetpotato virus problem. A wrap up meeting was held on the last day at KARI’s Regional Research Station Kakamega and was attended by the Deputy Director. The partners charted the way forward for the next implementing year. Prior to this joint planning meeting the Tanzanian and Kenyan teams held 2-day internal planning meetings (Tanzania in Arusha on 31st January to 1st March 2005 and Kenya in Nairobi on 4th to 5th February 2005). During these internal meetings, the detailed workplans and budgets for the year were developed.

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8.2. Joint Monitoring and evaluation of project activities Venues at three locations provided the opportunity to interact with grant participants to coordinate and discuss research and extension activities. The meetings were at the 9th Triennial Symposium of the International Society for Tropical Root Crops Meeting, November 2004, Mombasa, Kenya, The McKnight CCRP Grantee Conference, November 2004, Vaals, The Netherlands, and a formal gathering of all East African McKnight grant participants, February 2005, Nairobi, Kenya. Dr. C.A. Clark, a sweetpotato plant pathologist, visited Kenya in February 2005. This was an opportunity to review research conducted by Douglas Miano. 8.3. Challenges Several challenges were experienced by the project partners during the current implementation year. The problem of communication still persists but this has considerably been minimized. Lack of internet access in some key centres like Kakamega and Ukiriguru made the communication situation worse. In the next project year possibilities of dial-up connectivity to these two centres will be explored. Transport is still a big problem. The project continues to rely on old vehicles for most of the participatory activities. No immediate solutions are envisaged for this problem. The principal investigator has added responsibilities as the coordinator of KARI’s Biotechnology program. This is a challenge to the coordination office. A possible solution to this problem will be to set up a coordination secretariat headed by the coordinator and an assistant who will be one of the project scientists preferably based in Nairobi. Mrs. Violet Gaathara a social scientist based at the National Agricultural Research Laboratories will be nominated to take up this responsibility. Mrs. will be assisted by one of the coordinators secretaries particularly in typing and communication duties. The role of the assistant will be agreed upon as soon as possible and immediately communicated to the program manager and the project partners. On the project side four major themes are seen as the future challenge to the project. These include • Marketing of the sweetpotato and its products. • Seed multiplication and distribution particularly for dry areas. • Post-harvest value addition including development and improvement products. • A holistic approach to the farm family’s livelihood including his production system,

health and nutrition and income generation. These will form the basis for developing the project’s approach in the next phase. 8.4. Way forward • Completion of the germplasm characterization and long term characterization stratergies.

Within the next budget provision will be made to host discussions between the players in development of the molecular markers systems. This will be followed by use of falcilities available at the Bioscience falcility (BECA) in Nairobi to quickly complete the molecular analysis studies. The morphological and disease response studies will be concluded and the core collection identified. These will virus-cleaned, transferred to the Kenyan Genebank and duplicated in CIP, Lima world sweetpotato collection.

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• Publication and dissemination of the project documents will be a major in the next project year. This will include manual, reports, farmer pamphlets and refereed journal articles.

• A review of the project will be carried out to determine the strong and weak points and suggest the best way forward in which project outputs can produce bigger impacts amongst poor rural communities in the region.

• Efforts will be made to institutionalize the bulk of the projects breeding activities to the national research organizations and the international potato centre.

• Training of PhD and MSc. students will continue. • The work on the beta-carotene genes pathway will be concluded. • Policy workshops will be organized to create awareness amongst policy makers of the

projects outputs. • Small studies will be commissioned to look at possible research interventions in the four

challenge areas identified above. 8.5. Acknowledgement

We wish to thank our partner institutions for fully supporting us in carrying out this work. We are also grateful to the Collaborative Crop Research Program of the McKnight Foundation for financing this work. Finally we thank all those farmers, office staff, CBOs, NGOs, scientists, extension officers, managers and others who worked relentlessly with us in ensuring that this work is conducted successfully..

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LIST OF ABSTRACTS FOR ISTRC WORKSHOP

Preliminary analysis of diversity among East African Sweetpotato cultivars (Ipomoea batatas) using morphological and Simple Sequence Repeats (SSR) Markers Gichuru1 V., Aritua1 V., Lubega2 G.W., Edema1 R., Adipala1 E., & Rubaihayo1 P.R. East Africa is considered to be a secondary center of diversity owing to the wide range of sweetpotato varieties found there. In this study, we analyzed the diversity among sweetpotato cultivars from distinct agro ecologies in Kenya, Uganda and Tanzania using morphological and simple sequence repeats (SSR) markers. The morphological analysis used the CIP Research Guide 36. Phylogenetic analysis using UPGMA gave low bootstrap values and most of the cultivars were in the 0.1-0.4 Nei’s genetic distance from each other. This shows a close genetic relatedness. At a bootstrap value of 57 %, the cultivars formed two major groups: A and B. Further analysis of the cultivars was done using four SSR primers. Each primer pair was able to generate between one and three polymorphic fragments. Phylogenetic analysis by UPGMA of the SSR data revealed cultivars separating at a low bootstrap value of 54 %. Majority of the cultivars were in the 0.1-0.3 Nei’s genetic distance from each other. In both morphological and molecular analysis, the cultivars from Tanzania were found to cluster close to each other suggesting that they are slightly morphologically and genetically distinct from the Kenyan and Ugandan cultivars. AMOVA was done to further examine the relationships. Greater diversity was found with molecular data than with morphological data because it revealed presence of a population structure. The results of this study suggest that morphological analysis should always be complemented with molecular data when examining sweetpotato diversity. Genotype-by-Environment Interactions for some selected Sweetpotato Clones under different Agro-ecological Zones in Kenya S.M Agili, J.P.Ndolo. J.Korir and J.K. Mugo Five improved breeding lines of sweet potato [(Ipomoea batatas (L)] clones 56682/03, 292-H-12, NK-L-22, 389a-H-12, and 91/218, and 5 locally collected clones K117, Namaswakhe, , Odinga, Polista, SPK004 were evaluated in five agro-ecological zones in Kenya in order to assess genotype-environment interaction and to identify clones with desirable traits. A combined analysis of variance (ANOVA) was done on collected data to detect GXE effects. Stability assessments of individual clones were done using the Finlay and –H-Wilkinson (1963) regression coefficient (b=1). The genotype x environment interactions was significant (p=0.01) for number of large roots and total root yield. The storage yield of clones across the seven environments ranged from 12.74t/ha to 22.46 t/ha with a population mean of 16.96 t/ha. The high yielding clones in central highlands included K117, 91/218 and 5668203, while clones Odinga and NK-L-22 did poorly in the Lake Victoria Zone. Varieties 91/218, 389a-H-12, Polista and 292-H-12 with b values equal to or less than one and high root yield could be considered generally adaptable or stable. These varieties may be recommended for production in all sweet potato growing areas of Kenya. Namaswakhe, 5668203, K117 and Odinga with high root yield and b value significantly above unity (b>1.0) were considered unstable, but high yielding in favourable environments.

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Participatory evaluation of OFSP varieties in central and eastern zones of Tanzania

N. Luambano, R. Kapinga, K. Mtunda, M. Yongolo and C. Kitundu

Participation of farmers in selecting varieties in breeding activities is an advanced technology towards release of varieties acceptable to farmers. The Uniform Yield Trial using promising varieties selected from Advanced Yield Trial was conducted at Central and Eastern zones of Tanzania using ten and thirteen varieties respectively. Two local Orange Fleshed Sweetpotato (OFSP) varieties namely Mayai and Carrot-C were included for comparison during assessment. At the harvesting stage farmers were invited to assess the performance of the varieties in fields and to taste after cooking. Data on weight, virus, number of plants harvested, plants with and without roots, marketable and non-marketable varieties and their weight, weevil, rotting, cracking, root yield and dry matter were taken by breeders. Farmers were allowed to assess the varieties individually and then as a group to choose the best varieties and the least ranked varieties by pair wise ranking method both in fields and when cooked. Simama, Ukerewe, 2001/261 and 2001/264 varieties were selected as the best in Central zone of Tanzania in filed and when cooked. In Eastern zone, among thirteen (13) varieties planted, Ukerewe and Simama varities were selected in field and when cooked while 261 and W-151 varieties were among the best in field. The same varieties were least ranked when cooked. Other varieties highly ranked when cooked were Jewel and Jonathan. This paper discusses the results from breeders and that used by farmers in selecting the varieties acceptable to them for their sustainable development.

Demonstration of processing OFSP and linking farmers from western Kenya to markets Nungo R.A, P.J. Ndolo, R. Kapinga, S. Wasike Traditional methods of processing sweetpotato (Ipomoea batatas) in Kenya have been limited to washing, peeling and boiling. Market opportunities for sweetpotato have been limited to fresh white or cream fleshed roots for minimal amounts of money. Kenya Agricultural Research Institute (KARI) in collaboration with the International Potato Center (CIP) developed a range of OFSP (contain βeta carotene that is a precursor of Vitamin A) with considerable dry matter, good for processing and processing techniques. Processing reduces the bulkiness of sweetpotato, enhances shelf life and makes it available over long distances. Processing adds value to product, gives wider marketing, diversifies use and hence gives better price. The objective was to demonstrate and train farmers in quality dry chips processing and later determine factors that hindered marketing of the products. This was carried out through demonstrations and training of farmers in quality dry chips processing, visits and discussions with different food processors. Stakeholders discussed and selected potential markets identified packaging material, identified transport delivery service and linked farmers to the market through networking. Two demonstrations and trainings in processing quality dry chips were carried out in Gamalenga village of Vihiga District and Kajulu village in Kisumu district with an average attendance of 45 farmers. Three food processors were visited as potential market for the processed sweetpotato. One of the processors in Nairobi was linked to the farmers. Lined gunny bags that could carry 120 kilograms of dry chips were identified and accepted for use by farmers. Involving a new

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group in processing and marketing strengthened partnerships between KARI and Africa-NOW. One transport service delivery was identified based on affordable cost and mode of delivery at the processing site. Two farmer groups were linked to the market and a total of 1,478.9 kgs of quality chips worth Ksh. 118,312, were delivered to the processor. In conclusion, the study showed there was high market potential for processed chips. The supply of chips is below the demand and there will be need to put more farmers on board for processing. The farmers will have to practice staggered planting to be able to supply according to demand. Recent Advances in Sweetpotato improvement in Eastern Africa Gichuki S.T. Sweetpotato is an important food crop in Eastern Africa. For several decades the crop was practically ignored with minimum investments in its research and development. But in the last 10 years there has been significant attention given to this food crop that has resulted in its improvement. Several factors have contributed to this turn of events. Key amongst these have been an improved research capacity in the region and the decline of cassava production in the Lake Victoria basin due to effects of extremely virulent strains of the East African cassava mosaic virus. In addition recognition of the importance of sweetpotato and its potential contribution to solving the problem of rural poverty and nutrition enhancement has resulted in more funding being availed for the improvement of the crop. Current projects funded by various donors and the Eastern African governments have a goal of improving sweetpotato productivity and sustainability through collaborative researches on germplasm conservation, crop improvement, and development of technology for planting material propagation. Participatory rural appraisals and baseline studies have been conducted in several key sweetpotato production regions East Africa. Low crop yields, lack of high-yielding-early varieties, pests and diseases, poor management and marketing have been cited as major constraints to production. Promotion of drought-resistant crops, kitchen-gardens, and post harvest processing training has been suggested as potential interventions to address rural poverty in the region. Hundreds of sweetpotato varieties have been collected in the entire region and are currently being evaluated for morphological, Agronomic and molecular characters. In addition hundreds of introduced superior varieties and products of the breeding programs have been evaluated across different agro-ecologies. To boost adoption of resultant technologies, farmer field schools for technology development and transfer have been initiated. In addition research centers have multiplied clean planting material for secondary multiplication and distribution by local NGOs and CBOs. Training and provision of support services has greatly enhanced the capacity of the local scientists and extension personnel to address the constraints to sweetpotato production. This has ranged from degree related training short courses and field workshops involving farmers. Deployment of high B-carotene sweetpotato varieties with farmer preferred culinary qualities in East Africa S. Tumwegamire, R. Kapinga, S. Agili R. Mwanga, P. Ndolo, H. Saleh and E. Marandu The reported over 7 million t of sweetpotato produced annually in Africa is principally from the East African region and the immediate neighbouring countries of Rwanda and Burundi. This is the same region that manifests severe effects of vitamin A deficiency (VAD) effects among the rural poor communities. Since late 1990s sweetpotato has been fronted in East

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African region as one of the promising food based approaches to combat malnutrition, particularly VAD. It has been shown that by substituting white types with orange types of sweetpotato by farmers in the region, 50 million children under the age of 6 years will not be affected by VAD. Thus efforts have been made by scientists and their development partners to develop and deploy sweetpotato varieties that have high levels of B-carotene and farmer preferred culinary qualities. This paper therefore highlights results of these efforts. International Potato Centre, CIP has responded by introducing and distributing seeds and clones targeting high dry matter and high beta-carotene. To date ninety-three seed families and over 50 advanced clones have been introduced and distributed to over ten countries in sub-Saharan Africa. In East Africa national programs have received at least 15 of these clones and have been evaluated for adaptability and acceptability. Most preferred varieties have been identified in different countries and include Zapallo, Tainung 64, W - 151, jewel, Mafutha, Jonathan, Ejurnula. Over a half million additional seeds produced in the region by Uganda national sweetpotato program. Some local adapted varieties have been identified in the region and are being targeted by CIP for breeding programs. Seven local varieties from Kenya and one from Uganda have been cleaned up at PQS - Muguga, Kenya and are ready for CIP to distribute within the region. Thus, today, both farmers and development increasingly perceive sweetpotato governmental and non-governmental agencies as a most contributing way to eradicate VAD related problems among the rural populations. Impact of improved sweetpotato varieties in western Kenya farmers' perspectives M. Odendo, P. Ndolo and R. Kapinga Sweetpotato is an important food security crop in western Kenya due to its ability to give satisfactory yield under adverse conditions. However, production of the crop is mainly constrained by lack of high yielding varieties with consumer acceptable attributes, lack of healthy planting materials, pests and diseases, and poor marketing. To improve sweetpotato production, KARI in partnership with CIP, fanners and extension providers, introduced five improved sweetpotato varieties, Mugande, Kemb 10, Pumpkin, SPK 004 and Kakamega 013 in western Kenya between 1994 and 1996 and also promoted sweetpotato processing and utilization technologies as a means to improving market opportunities. In 2001, a survey was carried out to assess adoption of the improved sweetpotato varieties, elicit farmerbased indicators of impacts and evaluate magnitudes of the impacts of the new varieties; and identify factors that enhance or lessen adoption and attainment of the impacts. The study involved sen-dstructured interviews of 192 individual farmers and eight focus group discussions. Adoption of the improved varieties ranged between 41 and 72 percent, whilst a paltry 10-20% adopted processing and utilization technologies. The most widely adopted varieties were Mugande, SPK 004 and Kemb 10. Sweetpotato varietal attributes, especially relatively high yield, early maturity, 'good taste', suitability for multiple uses, drought tolerance and long in-ground root storage explained the adoption. The adoption of the new varieties resulted in improved self-sufficiency in food supply by at least 20 percent, whilst root maturity period was reduced by between 14 and 30 days. The main constraints to attainment of even greater impacts were lack of appropriate planting materials on sustainable basis, and attack of roots by moles. We conclude that more involvement of farmers in sweetpotato breeding and variety evaluation, and addressing the constraints are likely to improve sweetpotato production.

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Performance, foliage, and root yield of sweetpotato clones at Katumani and Kiboko in semi-arid eastern Kenya Githunguri C. M. Sweetpotato production in Kenya is constrained by several biotic and abiotic factors. Katumani seeks to develop sweetpotato varieties that are widely adapted, high yielding, early bulking, drought tolerant, resistant to major biotic and abiotic stresses and have high dry matter and Beta carotene contents. Fortyeight sweetpotato clones selected from the clonal trial at Katumani were planted in Kiboko in September 2003. Two other trials consisting of 15 entries each of sweetpotato varieties developed at Kakamega and introductions by the International Potato Centre were established at Katumani during the 2003 long rain season. The best clones were selected based on their rate of establishment, vigour, number of roots, foliage and root yield. In the preliminary yield trial, clones SPK-023 had significantly higher root yields while NKA-006-008 had significantly better establishment than most clones. Results from the advanced yield trial indicate that clones 320/06,91/218, 56682/02, 91/192, 56682/03 gave high root yield and dry matter content and could be advanced for on-farm trials. Clones 56682/02,91/218 and New Kawogo had significantly higher number of large roots than other clones. Clones 91/52, 91/52 had significantly higher dry matter content than the highest yielding clone 320/06, which had a dry matter content of 25.20%. In the National Performance Trial, the highest yielding varieties were K117, Odinga, Polista and 91/218. Clone K117 had the highest total yield, number and yield of large roots. Though establishment of cultivars is important, farmers could discard low yielding clones, which had high establishment. Conversely, high yielding clones that establish poorly are unlikely to be adopted by fanners. There seems to be a negative relationship between root dry matter content and total yield. There was a positive relationship between the number of roots and total yield, suggesting that breeders should select for high number of roots. Characterising the response of sweetpotato to infection by sweetpotato virus disease D. W. Miano D. R. LaBonte and C. A. Clark Distribution of Sweetpotato feathery mottle virus (SPFMV, genus Potyvirus, Potyviridae family) in sweetpotato is highly variable, with more tolerant materials showing higher variability in distribution, at times leading to absence of the virus in an increasing proportion in the growing shoots. Understanding the response of sweetpotato to infection by Sweetpotato virus disease (SPVD), a result of synergistic interaction between SPFMV and Sweetpotato chlorotic stunt virus (SPCSV, genus crinivurus, family Closteroviridae), may explain this variability, leading to an understanding of the characteristics of an SPVD-resistant plant. This research describes efforts towards characterizing the response of resistant and susceptible materials in terms of SPFMV and SPCSV distribution within the plant, virus multiplication and virus movement and the role of other potyviruses in SPFMV multiplication and disease development. Preliminary findings, using real-time PCR to study SPFMV and SPCSV distribution, and the role of other potyviruses in SPFMV multiplication are discussed.

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Enhancing sweetpotato production and utilisation through processing among the rural families in Kiambu District in central Kenya Gathaara V.N., Gichuki, T.S., Priscilla, K. and Ngugi, N Sweetpotato is one of the world's most important food crops and which performs well under wide climatic conditions. Sweetpotato is high in food value and in terms of calories a hectare of sweetpotato can feed twice as many persons as rice and five times as many as maize. In Kenya, utilisation of sweetpotato is limited to use of the tubers in the flesh form and feeding of the vines to the livestock. In the flesh form majority of the households either boil or roast the tubers. It is now becoming evident that inclusion of processing and market oriented development of agricultural sector is needed if farmers were to reap full benefits from the sweetpotato. What today is an element of household food preparation may tomorrow be an interesting processing for entrepreneurship. Market orientation and diversification in agriculture combined with processing and marketing can considerably contribute to reduction of food losses, improvement in food and nutrition, income generation at household level and over all stimulation of production,which remains the backbone of Kenyan economy. Development in root and tuber processing technologies arises from the need to diversify on the utilisation of sweetpotato at the household level to address the food and nutrition security and poverty alleviation. A total of 49 farmers (27 male and 22 female) have been trained on processing and utilisation of orange-flesh sweetpotato. Fourteen orange-fleshed sweetpotato products were developed, evaluated and ranked though the FFF approach. The FFS was involved in hands-on product development while evaluation of the products based on taste, colour, palatability, and general acceptability and ranking was based on the product's use(s) as either for subsistence, income generation, or both. Identification of DNA markers linked to resistance to the sweetpotato virus disease D.W. Miano, D.R. LaBonte and C.A. Clark Sweetpotato virus disease (SPVD) is a serious threat to sweetpotato production in East Africa. The disease is a result of synergistic interaction between the sweetpotato featherly mottle virus (SPFMV, genus Potyvirus family Potyviridae) and Sweetpotato chlorotic stunt virus (SPCSV, genus Crinivirus family Closteroviridae). Interaction of SPCSV with other viruses especially potyviruses such as Ipomoea vein mosaic virus (lVMV) and Sweetpotato virus G (SPVG), and Sweetpotato leaf curl (SPLCV) may also result to SPVD. Optimal control of SPVD is mainly by use of resistant sweetpotato cultivars. Developing resistant materials takes time and is made difficult by the genetic nature of the sweetpotato plant. Early identification of resistant sweetpotato would save time in selecting materials for use in breeding programmes. Understanding the response of such resistant materials to infection by the main viruses causing SPVD will be an important step towards developing resistant lines. Use of DNA marker technology and discriminant analysis in identifying trait-linked molecular markers for SPVD will greatly help in early identification of resistant germplasm and also accelerate the time of developing resistant cultivars.

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Use of single nucleotide polymorphisms (SNPs) of expressed genes as a marker system to merge existing linkage groups in hexaploid sweetpotato Ericka A. Pestana, Maria Berenyi, Albert Kriegner, and Kornel Burg. Comparative analysis of gene expression in drought sensitive and tolerant sweetpotato genotypes Joanna Jankowicz, Maria Berenyi, Kornel Burg, Jerzy Kruk Using public domain software to integrate sweetpotato accession collection data into a GIS database A. Villordon, S. Gichuki, H. Kulembeka, S.C. Jeremiah and D. Labonte Analysis of sweetpotato passport data using Geographical Information Systems (GIS) and characterisation with morphological and molecular markers W. Njuguna, G.M.Muluvi, J. Machuka and S.T.Gichuki Morphological and molecular characterization was done for a total of 595 sweetpotato varieties randomly collected from western, Eastern and Central Kenya. Using descriptors developed by the International Plant Genetic Resources Institute (IPGRI) and the International Potato Center (CIP), differences between varieties in vine, leaf, and storage root characters were recorded. A total of 24 descriptors were selected for analysis. Discriminate analysis and clustering procedures were used to analyze similarities between varieties based on the morphological data. The passport data of all the 595 accessions was analyzed using DIVA-GIS program. Five ISSR markers have been used to generate molecular profiles for 22 sweetpotato varieties. Relationships between varieties have been analyzed by dendrograms using UPGMA clustering procedure and multidimensional scaling. The comparison between morphological and molecular analysis is discussed. Participatory evaluation of sweetpotato varieties in central and eastern Kenya using the farmer field school approach Gathaara V.N; Gichuki,T.S.; Ngugi J.N.; Ngigi,G.K. Priscilla, K and Kihurani, A.W. Sweetpotato (Ipomea batatas L.) is a crop with high food value and is one of the world's highest yielding crops. I in Kenya, the crop can be grown under a wide range of climatic conditions and its contribution to food security and nutrition cannot be overlooked. The crop's potential production levels have not been achieved in the past due to lack of attention by agricultural researchers leading to loss of its germplasm. I lit, c rop has Aso been lacking a market-oriented development such as technologies towards value addition. I However, more emphasis is now being given to the crop to enhance its contribution to the national food security and poverty eradication. The McKnight sweetpotato project is using the FFS approach in the introduction and evaluation of the various varieties alongside the orange-fleshed type. From this evaluation, it is expected that the farmers will be able to select and adopt the most superior varieties To date a total of six FFS have been established in Central and Eastern Kenya with a membership Of about 120 men and women farmers. KARI

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researchers and extension officers in the Ministrv of Agricultural (MOA) are doing facilitation of the FFS. Farmers are fully in charge of running the FFS. The FFS members have so far gained the necessary knowledge and skills in sweetpotato production and value addition. The approaches being used in the FFSs include Participatory Technology Dernonstrations (PTDs), Agro-ecosvstems Analysis (AESA) and practical product development. All the P I I plot, ir(, performing well and the crop is at the harvesting stage. In regard to value addition, a total ot 1. sweetpotato products have been developed. Observations made so far have shown that FFS is an effective approach to technology evaluation and transfer. MSc Research Proposals Participatory Evaluation of Sweetpotato Varieties for Commercial and Domestic Use in

Western Kenya (MSc Thesis research proposal)

Johnson K. Kwach, Maseno University

Sweetpotato [Ipomoea batatas (L.) Lam] is a drought tolerant and food security crop grown by small-scale farmers in various agro ecological zones of western Kenya. However, intensive production has been constrained by lack of improved varieties, pests, diseases and land scarcity, resulting in declining production. Current farmer production ranges between 5 - 13 tons ha-1 while the potential is 30 t ha-1 with new improved varieties. But lack of farmer involvement has led to non- adoption of these new varieties. Therefore, there is need to evaluate and select varieties with the involvement of farmers for development of higher yielding, disease resistant / tolerant and pest resistant varieties that are also nutritionally rich in β-carotene, a precosur for Vitamin A. Kenya Agricultural Research Institute (KARI) in collaboration with International Potato Centre (CIP) has identified ten improved sweetpotato varieties that will be evaluated using participatory research approaches during the 2005 long rains season. The study will be conducted in four sites covering the major sweetpotato production agro-ecological zones of western Kenya. namely; Kabondo (AEZ UM1-3), Ndhiwa (LM3 & 2), Rangwe (LM1), and Kendu Bay (LM3). A mother and baby trial design will be used. The mother will be located at a central location and be surrounded by ten farmers who will each host a baby trial set and be involved in the evaluation. Data will be collected and analysed using SAS and SPSS Statistical programs. Results of both biophysical data and evaluation process will be used to select for the preferred newly introduced sweetpotato varieties for commercial and domestic for adoption by the targeted communities. Other publications and workshop papers Sweet potato in the food system of the Lake zone of Tanzania (In preparation) Sonda G, Jeremiah S.C. Kuembeka H.P and Mwalukasa E.E A Participatory Rural Appraisal study was conducted in the Lake zone of Tanzania in 2003, the aim of the study was to collect indigenous technical knowledge on sweet potato and understanding sweet potato production constraints. Six villages from three districts of the lake zone were covered (two villages in Magu district, two villages in Sengerema and two in

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Meatu). Sweet potato was rated between 2nd to 4th in importance compared to other food crops. Drought tolerance and contribution to household food security was major criteria for ranking by most farmers. Pests and diseases, unavailability of improved sweet potato varieties, lack of planting materials and storage pests were the major constraints to sweet potato production. Most farmers are dependent on Agriculture as main source of income. Contribution of Agriculture to total household income ranges between 40% to 95%. Despite this there is little investment in Agriculture activities with more than 50% of income generated used for purchase of food and clothing. Several different varieties grown but differ between areas, but same varieties may have different names. Taste, marketability, tolerance to pests and disease, drought tolerance, yield, maturity period and intended utilization are the farmers criteria for selecting varieties. The study revealed that , in order to help farmers in sweet potato production , participatory breeding and evaluation of varieties is essential and to enhance their acceptability and adoption. More efforts should be put on breeding for resistance against major constraints mentioned by farmers. Availing planting materials to farmers is a key issue. Sweet potato production, its opportunities and constraint in Southern Highlands (In

preparation)

D.H. Mende, C.D. Kabungo and B.J. Gondwe Sweet potato (Ipomoea batatas) is an important subsistence food crop grown in almost all agro ecological zones of Tanzania. Despite research efforts to increase the productivity of sweet potato per unit area, yields increase in farmers fields have been very slow compared to other crops. This situation might be contributed by a lack of farm – level information about the crop, cropping systems and socio-economic constraints in sweet potato producing areas. A survey was conducted in two Regions namely Ruvuma and Mbeya in the Southern Highlands of Tanzania. One district per region and two villages per district were selected based on the importance of sweet potato relative to other food crops and its contribution to the household food security and income. The main food crops grown in the areas include Beans, Maize, sweet potato and sorghum; in Songea cassava is also grown. Sweet potato in the system is ranked 4th to 5th but it has contribution towards food and cash income. Agriculture is the main source of income in both Mbeya and Songea, its contribution was mentioned to be about 80.4% and 92.5% in Mbeya and Songea respectively. Other sources of income are small business (37% )for Mbeya and 34% for Songea. Livestock contribution was mentioned to be 17.4% and 11.3% for Mbeya and Songea. Sweet is sold in local and district markets. The prices is influenced by size and colour of tubers as well as variety.

Only four varieties were recorded in the study area sourced from Sumbawanga in Rukwa region, Usukumani in Mwanza region and Kagera region. Important attributes attached to these varieties include Good taste, Marketability, Yield, tolerant to drought and availability of plating materials. Production of sweet potato in those areas has advanced a bit as farmers use fertilizers hence increase yields. Production of sweet potato in the southern highlands is affected by many constraints including, the constraints include lack of capital, labour shortage, pests, and diseases, lack of planting materials, market problems, and low producer prices. Farmers cope with these constraints by moving to new areas when land become scarce, establishment of new local markets, hiring labour during peak periods and buying planting materials from neighboring villages during shortages.

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Development of a web-accessible GIS database as a tool for sweetpotato germplasm collection activities in east Africa Arthur Villordon An oral presentation at the American Society for Horticultural Science Annual Meeting held on 17 July to 20 July 2004, Austin, Texas. Using GIS tools to model the potential distribution of sweetpotato germplasm in Sub-Saharan Africa (In preparation) Arthur Villordon This manuscript includes germplasm accession data from Kenya, Tanzania, and Uganda and represents a cooperative work among the McKnight CCRP-supported sweetpotato projects in the region. Occurrence data from all three countries will be used to model the potential distribution of sweetpotato germplasm in Sub-Saharan Africa to identify areas for additional exploration and collection activities. This manuscript will be submitted for review and publication in HortTechnology. Associating molecular markers with phenotypes in horticultural crops using multivariate statistical modeling Mwamburi Mcharo Ph.D. dissertation. May 2005. Louisiana State University. Associating molecular markers with virus resistance to classify sweetpotato genotypes Mwamburi Mcharo et al.

Refereed manuscript a cooperative work among the McKnight CCRP-supported sweetpotato projects in the region. Publication is set for May 2005 in the Journal of the American Society for Horticultural Science. Molecular Marker Variability for Southern Root-knot Nematode Resistance in Sweetpotato Mwamburi Mcharo et al.

Refereed manuscript set for publication in Euphytica in 2005.

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Molecular Marker Variability for Southern Root-knot Nematode Resistance in Sweetpotato M. Mcharo An oral presentation presented at the American Society for Horticultural Science Annual Meeting held on 17 July to 20 July 2004, Austin, Texas. Comparison of Logistic regression and discriminant analysis in associating AFLP markers with beta-carotene and sugar content among sweetpotato clones M. Mcharo An oral presentation entitled “” was presented at the National Sweetpotato Collaborators Group Annual Meeting held on 5 February to 6 February 2005, Little Rock, Arkansas. (M.