Euphytica 46 : 79-84, 1990.©1990 Kluwer Academic Publishers . Printed in the Netherlands .

Inheritance of some morphological traits in grain amaranthus

V.K. Gupta & S. GuduDepartment of Crop Science, University of Nairobi, P.O. Box 30197, Nairobi, Kenya

Received 27 December 1988 ; accepted in revised form 1 May 1989

Key words: Amaranthus species, grain amaranth, morphological traits, inheritance

Summary

Intraspecific crosses involving five cultivars of Amaranthus hypochondriacus and two from A. caudatus werestudied to investigate the inheritance of five morphological traits (seed coat colour, inflorescence colour,seedling colour, oval leaf mark and purple leaf mark) . Seedling colour, inflorescence colour, seed coat colourand oval leaf mark segregated to a 3 :1 ratio and therefore each was controlled by a single dominant gene . The

purple leaf mark segregated in 9 :7 ratio and hence may be controlled by two dominant genes . Simultaneoussegregation for seed coat colour and inflorescence colour gave a ratio of 9 :3 :3 :1 . Similar genetic ratio wasobserved for the simultaneous segregation for oval leaf mark and inflorescence colour . It was suggested thateach of these traits is controlled by independent genes .

Introduction

The grain amaranthus (Amaranthus hypochondria-cus, A . cruentus, A . edulis and A. caudatus)evolved as a crop in Central and South Americawhere their production was suppressed by Spanishconquerors because they were associated with pa-gan ceremonies (Sauer, 1950) . The grain ama-ranths are presently receiving a lot of research at-tention because of their high lysine content, wideadaptability to various ecological zones - droughttolerance and due to the fact that they are C4 plantswhich are photosynthetically efficient (Nat . Acad .Sci. 1975 ; Vietmeyer, 1982 ; Laidig et al. 1984) .They are now grown as a minor grain crop in partsof Central and South America and India and as aleafy vegetable in Asia and Africa (Grubben, 1976 ;Nat. Acad. Sci ., 1984) .

Few genetic studies have been reported in thecrop. Walton (1968), reported that perianth colour

was a homogenic trait . Okuno & Sakaguchi (1982)studied the inheritance of starch characteristics inthe perisperm ofA . hypochondriacus and reportedthat the difference in the non glutinous and gluti-nous endosperm was due to a single gene with thenon glutinous allele dominant over the glutinousallele. Coons (1982) reported the inheritance ofblack and white seed coat colour to be controlledby a single gene with black being dominant overwhite . In genetic analysis of six colour character-istics in grain amaranths Kulakow et al . (1985)found that seed coat colour was controlled by twoloci in A . hypochondriacus and A. caudatus . Theyobtained segregation ratios of 12 :3:1 for black-yel-low-pale and black-brown-pale colour classes re-spectively. A leaf spot trait segregated as a singledominant trait gene while a leaf V-mark trait wasfound to be governed by a single dominant gene . Anumber of contrasting morphological traits havebeen investigated . More knowledge on inheritance

This research was supported by Grant No . AMA-KE-4-83-22 (CRG GRANT) from the National Academy of Science, U .S .A .

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of the crop's diverse morphological traits is essen-tial for the characterization of cultivars for germplasm conservation and identification of geneticmarkers necessary for the improvement of thecrop. It may also provide some idea about thelinkage groups and genome organization in thecrop .

The present study was therefore initiated to in-vestigate the inheritance of some of the morph-ological traits and also to find out linkage relationsof different genes .

Table 1 . F2 segregation ratios for some morphological traits

Materials and methods

A total of five cultivars of A. hypochondriacus(1008, 1024, 1023, Jumla and 723) and two cultivarsfrom A. caudatus (A-1113A- A-982) were used inthe study . Both A. hypochondriacus and A. cauda-tus have n = 16. The parents have normal meiosisand pollen and seed fertility . The sources and char-acteristic features of the parents are described be-low. The morphological traits investigated in thestudy include : Seedling colour, seed coat colour,

Crosses/Trials Trait and classes Total no .of plants

Expectedratio

x z df . -

A. hypochondriacus1008 x Jumla

Red1886

Green622 2508 3 :1 0 .053 1

1008 x Jumla 532 174 706 3 :1 0 .047 11008 x 723 102 31 133 3 :1 0 .203 1A. caudatusA-1113A x A-982 1423 426 1849 3 :1 3 .790 1A-1113A x A-982 83 24 109 3 :1 0 .377 1A-1113A x A-982 272 81 354 3 :1 0 .795 1

1008 x JumlaInflorescence colour

1223 3 :1 1 .453 1899 3241008 x Jumla 532 174 706 3 :1 0.047 11024 X Jumla 663 215 878 3 :1 0.123 11024 x Jumla 332 130 462 3 :1 2 .427 11023 x Jumla 702 238 940 3 :1 0.026 11023 x Jumla 340 110 450 3 :1 0.074 11023 x 723 545 196 741 3 :1 0 .832 1A. caudatusA-1113A x A-982 978 339 1317 3 :1 0 .385 1A-1113A x A-982 83 24 107 3 :1 0 .377 1A-1113A x A-982 272 81 354 3 :1 0 .795 1

A . hypochondriacus1024 X Jumla

Seed coat colour

638 209 847 3 :1 0 .048

A . hypochondriacus1023 x Jumla

Purple oval leaf mark

652 3 :1 0 .204 1Leaf mark484

Without mark168

1023 x Jumla 310 92 402 3 :1 0 .958 11008 x Jumla 899 324 1223 3 :1 1 .453 11008 x Jumla 532 174 706 3 :1 0 .047 1

A. hypochondriacus1008 x 723

Purple leaf markLeaf mark

Without mark110 9 :7 0.028 161 49

1008 x 723 177 127 304 9 :7 0 .481 1

inflorescence colour, purple leaf mark and oval leafmark . The specific crosses performed to study theinheritance of each of the traits are described inTable 1 .

Varieties

1008 - Originated in Nepal, Seeds for thestudy were obtained from Rodale Re-search Centre, U .S.A. Semi-dwarfvariety with green leaves, green stem,green inflorescence and white seeds .

Jumla - Ex-Nepal, obtained and improved lo-cally. Semi-dwarf variety with redstem, purple oval leaf mark which issituated at the centre of the leaf, whiteseeded with red inflorescence .

1023 - Medium-tall Mexican variety, ob-tained from Rodale Research Centre,U.S.A. It has red colour at the base ofthe stem, green inflorescence andwhite seeds .

1024 - Medium-tall Mexican variety, ob-tained from Rodale Research Centre,U.S.A. It has red colour at the base ofthe stem, green inflorescence and yel-low seeds .

723 - Tall variety, obtained from RodaleResearch Centre, U.S.A. It has redcolour at the base of the stem, redinflorescence and dark purple patchymarkings which spread on the laminaof young leaves . It has pale whiteseeds .

A-1113A - Obtained from Rodale Research Cen-tre, U.S.A. It has drooping green in-florescence, green stemmed and whiteseeded .

A-982 - Obtained from Rodale Research Cen-tre, U .S .A. It has dropping red in-florescence, white seeds and red col-our at the base of the stem .

Intraspecific crosses were performed betweenthe varieties with contrasting traits (Table 1) . Thefemales were emasculated, pollinated and the in-florescence covered by paper bags to prevent in-

terference from any stray pollen . In most cases F,seeds developed normally . To facilitate identifica-tion of the F, plants, marker characters were used .Plants with characters suspected to be genetic dom-inants were used as pollen parents . Hybrids weretherefore easily identified by the presence of themarker character .

The various segregating F2 populations werescored for different traits under field conditions .Seedling colour was scored shortly after germina-tion, the leaf markings were scored 4-8 weeks afteremergence because at this time they are expressedbetter, but after this period they start fading away .Inflorescence colour and seed coat colour werescored shortly after anthesis and at maturity, re-spectively .

The segregation ratio for each character was sub-jected to chi-square analysis to compare them withthe expected genetic ratios .

Results

Seedling.colour

All the F, plants from two different crosses in-volving green and red stemmed plants from A .hypochondriacus and A. caudatus seedling had redseedling stem colour. The F2 segregation ratioshowed 3 red to 1 green stemmed seedling colour(Table 1) .

Inflorescence colour

The F, plants from green and red inflorescenceparent crosses were all red flowered . In all thecrosses, the segregating F2 populations gave 3 redto 1 green flowered plants and a good fit to theexpected 3:1 ratio (Table 1) .

Oval leaf mark of A . hypochondriacus

All the F, plants from crosses of plants with ovalleaf mark, as pollen parent and those without theleaf mark as female parent, produced the oval leaf

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mark. The F2 populations segregating gave a ratioof 3 plants with the purple oval leaf mark to 1 plantwithout the oval leaf mark . This was also a good fitto the expected 3 :1 ratio (Table 1) . This shows thatoval leaf mark is dominant .

Seed coat colour of A . hypochondriacus

All the crosses between yellow seeded and whiteseeded parents gave yellow seeded offsprings, sug-gesting that yellow is dominant over white . Thesegregating F2 populations gave a ratio of 3 :1 yel-low seeded to white seeded plants (Table 1) .

Purple leaf mark of A . hypochondriacus

The Ft plants from crosses between plants with thepurple leaf mark and those without the leaf mark,had purple leaf mark. This shows that the purpleleaf mark is dominant over its absence . The F2populations segregated into two distinct classes in aratio of 9 :7, plants with purple leaf mark and thosewithout, respectively . The chi-square tests gave agood fit (Table 1) .

Simultaneous F2 segregation for two characters

Seed coat and inflorescence coloursThe F2 populations, from white seeded, red in-florescence x yellow seeded, green inflorescencesegregated into four distinct classes . Plants with redinflorescence and yellow seed coat, plants with redinflorescence and white seed coat, plants with

Table 2 . F 2 segregation for seed coat colour and inflorescence colour in A. hypochondriacus

Total no .of plants

Yellow seed White seed

Yellow seed White seedcoat colour

coat colour

coat colour

coat colour

green inflorescence and yellow seed coat, plantswith green inflorescence and yellow seed coat,plants with green inflorescence and white seedcoat. The four classes segregated into 9 :3:3 :1 ratio(Table 2) .

Purple oval leaf mark and inflorescence colourand oval leaf mark x green inflorescence and nooval leaf mark plants, segregated into four separateclasses of red inflorescence plants with and withoutoval leaf mark, and green inflorescence plants withand without the purple oval leaf mark and gave9:3:3:1 ratio respectively (Table 3) .

Discussion

All the crosses in A. hypochondriacus and A. cau-datus showed that red seedling colour is dominantover green seedling colour in the F t populations .The F2 segregation ratios did not show significantdifference from 3 :1 ratio . This suggests that seed-ling colour in the two species of grain amaranths iscontrolled by a single locus with two alleles . Thedominance of red seedling colour over green hadbeen observed earlier (De Vries, 1912 ; Coons,1982; Hauptli & Jain, 1985), however, its geneticinheritance was just recently reported by Kulakowet al. (1985) who also suggested that a single genecontrols the seedling colour .

The segregation of F2 populations for inflores-cence colour in A . hypochondriacus and A. cauda-tus crosses showed a good fit to 3 :1 ratio with redinflorescence colour dominant over green inflo-rescence colour . This suggests single gene controlof inflorescence colour . Similar observation hasbeen reported by Kulakow et al . (1985) .

Expected

X2

df.ratio

1024

487

150

150

39

847

9:3:3 :1

1 .801

3

Crosses Trait and Class

Red inflorescence Green inflorescence

Table 3. F3 segregation for purple oval leaf mark and red inflorescence in A . hypochondriacus

Red inflorescence

Green inflorescence

Total no . Observed Expected x2

df.of plants ratio

ratioNo. of plants

No. of plants

No. of plants

No. of plantswith leaf mark without leaf

without leafmark

mark

1023 x Jumla 444

134

1311024 x Jumla 233

78

68

All the Ft populations from crosses involvingyellow seeded and white seeded parents had yellowseeds indicating dominance of yellow seed coatcolour over white seed coat colour . From the F 2population segregation ratio, it can be suggestedthat the character is controlled by a single dialleliclocus . Coons (1982) obtained single gene inher-itance for black and white seed coat colours withblack being dominant in A. caudatus . Kulakow etal . (1985) found the inheritance of seed coat colourto be controlled by two loci in both A. hypochon-driacus andA. caudatus . This may mean that seedcoat colour may be controlled by single locus or agroup of loci . Amaranth offers quite a variety ofseed colouration, each of these should be studiedand its genetic control ascertained for a better un-derstanding of the genome organization in the ge-nus .The Ft plants from crosses involving parents with

oval leaf mark and those without oval leaf mark .

This implies that oval leaf mark is dominant . The F2segregation ratios fitted a 3:1 ratio, suggesting thatthe character is controlled by a single gene . Kula-

kow et al. (1985) reported the inheritance of twoleaf markers: a leaf spot and a leaf V-mark and thepresence of a third oval leaf marker which they didnot study. They suggested a single gene control forthe leaf spot and two gene control for the V-marktrait. They did not report the inheritance of theoval leaf mark .

The purple leaf mark was dominant over its ab-sence as indicated by Ft progenies of the relevant

crosses . The FZ segregation ratio fitted 9 :7 suggest-ing that the character is controlled by two comple-mentary dominant epistatic loci . Kulakow et al .(1985) described a V-mark trait in A . hypochon-

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48

757

9:3:3 :1

2.065

325

404

9:3 :3:1

1 .016

driacus which is controlled by two dominant epis-tatic loci . It is probable that it is the same or similarleaf mark reported here .

Simultaneous segregation for yellow seed coatand red inflorescence colour gave 9 :3:3:1 ratio .Chi-square test confirmed the goodness of fit to theexpected 9:3:3 :1 genetic ratio . On the basis of theobserved independent assortment of the two traitsand the monogenetic control for each of them it issuggested here that the two traits are controlled bytwo independent genes . More studies may be nec-essary to confirm this hypothesis .

Simultaneous for purple oval leaf mark and in-florescence colour suggested independent assort-ment of the two traits in A . hypochondriacus . Onthe basis of this observation, it may be suggestedthat the two traits are controlled by independentgenes located on different chromosomes .

A similar work has been reported by Kulakow etal . (1985) . Our studies have confirmed some oftheir results while in some cases we got differentresults. In case of seed colour Kulakow et al . (1985)reported that the seed coat colour is controlled bytwo loci while our study indicated that the yellow vswhite seed coat colour is controlled by a single

gene. Yellow being dominant over white . Similarlyearlier work by Kulakow et al . did not report theinheritance of oval leaf marker. Our study showedthat oval leaf marker is controlled by a single gene .Besides this, our study throws additional light ofthe simultaneous inheritance of two characterswhich has not been studied by the earlier workers .These results show and confirm the independentsegregation of two genes governing these charac-ters. This additional information is of value to un-

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derstand the inheritance of various traits in grainamaranth .

Acknowledgements

We are grateful to the Dean, Faculty of Agricultureand Chairman, Crop Science Department, Uni-versity of Nairobi, for providing necessary facilitiesand also to the National Academy of Science,U.S.A. for providing the funds. The material sup-plied by the Rodale Research Centre, U .S.A. isalso gratefully acknowledged. The experimentswere carried out by the junior author while work-ing as a research assistant in the project . We wish tothank Dr. P .O. Ayiecho for help in the initialstages in the preparation of the manuscript .

References

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Hauptli, H . & S .K . Jain, 1985 . Genetic variation in outcrossingrate and correlated floral traits in a population of grain am-aranth. Genetica 66 : 21-27 .

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Okuno, K. & S . Sakaguchi, 1982 . Inheritance of starch charac-teristics in perisperm of A. hypochondriacus. J. Hered . 73 :467 .

Sauer, J.D.,1950. The grain amaranths : a survey of their historyand classification. Ann . Miss . Bot . Garden . 37 : 561-619 .

Vietmeyer, N ., 1982. The revival of the Ameranth . Ceres FAOReview on Agriculture and Development . 15(5) : 43-46 .

Walton, P.D., 1968 . The use of Amaranthus caudatus in sim-ulating the breeding behaviour of commercial Gossypiumspecies . J . Hered . 59 : 17-18 .