Plant Breeding 110, 153—156 1993)© 1993 Paul Parey Scientific Publishers, Berlin and HamburgISSN 0179-9541

Short Communication

Monosomic Analyses of Yellow Rust and Leaf Rust Resistance Genesin Winter Wheat Cultivar Tengkang T

PANG JIAZHI, SUN RONGJIN, YANG ZHIGANG and ZHOU GIUYING

Institute of Grop Breeding and Gultivation, GAAS, 30, Bai Shi Quiao Lu, Beijing 100081, P. R. Ghina.

With 2 tables

Received April 14, 1992 I Accepted September 28, 1992Communicated by K. Leonard

AbstractA set of 21 monosomics of 'Ghinese Spring' was usedto locate the rust resistance genes of 'Fengkang 2',developed by the Ghinese Academy of AgriculturalSciences. The resistance to yellow rust race GY25was controlled by a dominant gene located onchromosome 5B and resistance to leaf rust race GL38was controlled by a dominant gene located onchromosome 5A in 'Fengkang 2'. Most likely thesetwo genes are new.

Key words: Triticum aestivum — yellow rust — leafrust — resistance — monosomic analysis

Wheat is one of the most important crops inChina. Yellow rust caused by Puccinia striifor-mis Westend and leaf rust caused by Pucciniarecondita Rob ex Desm are the main limitingbiotic factors in yield stability and yield poten-tial. YANG and Wu (1990) reported that P.striiformis evolved in China as an independentsystem. Therefore, knowledge of resistancegene loci is useful for understanding the dis-tribution of both pathogenicity genes in thepathogen and resistance genes in the host, aswell as for breeding for rust resistance inwheat. Unfortunately, only a few genes havebeen studied in resistant cultivars and resistantsource varieties in China. XIN (1984) reportedthat 'Fengkang 13' has the Yrl gene onchromosome 2A and another new gene locatedon chromosome 2B. Results of SHU et al.(1990) indicated that the cultivar 'Yantar' hastwo incompletely dominant complementary

genes for resistance to leaf rust race CL3 onchromosomes 5A and ID, and that the cultivar'Luqiyu' has one dominant resistance gene toyellow rust race CY25 on chromosome 2B.SHEN (1991) found evidence of a single domi-nant resistant gene to yellow rust race CY25 onchromosome 3B in BAU 233, recessive com-plementary genes on chromosomes 2A and 3Ain Fr84-4, and a single recessive gene onchromosome 7B in cultivar C39. PANG et al.(1991) reported that the cultivar 'Beijing 837'carries the gene Yr9 on chromosome IB (lBL/

IRS).The cuhivar 'Fengkang 2', developed by the

Institute of Crop Breeding and Cultivation atBeijing in the early 198O's, had resistance torusts and powdery mildew when it was re-leased. Its reliability and high yielding poten-tial have made it attractive to wheat growersfor a relatively long period in winter wheatareas of China. It is also used as a rust resistantparent for breeding programs, since it hasshown dominant resistance to rusts.

The purpose of the present study was tolocate the genes for yellow rust and leaf rustresistance in 'Fengkang 2' by monosomicanalysis and to determine whether 'Fengkang2' carries new resistance genes.

The study was carried out from 1988 to 1991, in anexperimental field with wire netting and in a glass-house in Beijing. The cultivar Tengkang 2' wasselected from a cross between 'Youmanbai 4' and

U.S. Cle ance Center Cod. S,...»e«.: 0179-9541/93/1002-0153$02.50/0

154 JiAZHi, RONGJIN, ZHIGANG and GiUYiNG

'Lovrin 10' which is immune or resistant to domi-nant races of yellow rust and leaf rust in bothseedling and adult stages. A set of 21 monosomiclines of 'Ghinese Spring' (GS) developed by E. R.'Sears was introduced from Ganada. These lines aresusceptible to races GY25 and GL38. 'Fengkang 2' asa male parent was crossed with each monosomic lineas a female parent, and Fj seeds from each cross weregerminated in petri dishes. Two roots from eachseedling were collected and fixed in 3 : 1 Garnoys'solution, the seedling was labeled and kept in lowtemperature conditions. Fj monosomics wereselected on the basis of chromosome counts of roottip cells stained by using the Feulgen technique.Only those seedlings with 2n = 41 were transplantedto the glasshouse. Spikes were bagged to ensure selfpollination at flowering. F2 seedlings generated fromF] plants with 2n = 41 were tested for reaction toyellow rust race GY25 and leaf rust race GL38 in theglasshouse.

The F2 progenies, 'Fengkang 2', 'Ghinese Spring'disomics and a susceptible check cultivar were grownin the glasshouse and inoculated with urediosporesof single-pustule isolates of Pucdnia striiformis raceGY25 and P. recondita race GL38 (provided and

identified by Institute of Plant Protection, GAAS).Urediospores were dispersed in talc powder anddusted on to the seedling when the first leaf was fullyexpanded and the second leaf starting to emerge. Theinoculated seedlings were then placed in dark, humidconditions at 10 °G for 24 hours before being re-turned to the glasshouse. Tests were carried out inspring 1991 when temperatures in the glasshouseusually ranged between 8—18 °G. Illumination wasprovided for 14 hours per day by fluorescent bulbs.After two weeks, infection types on single plantswere classified as described by STAKMAN et al. (1962)(0—2 = resistant; 3—4 = susceptible). Ghi-squaretests were used for analyzing the segregation data forgoodness of fit to expected ratios.

Yellow rust: 'Fengkang 2' showed a very re-sistant (O;) seedling response to the culture ofyellow rust race CY25, whereas 'ChineseSpring' was susceptible (3—4). Disomic Fiplants produced infection type O;. The sameresult found in field observation indicate thatthe resistance is dominant. As shown inTable 1, segregation in the disomic F2 popula-

Table 1. Segregation for resistance to yellow rust race GY25 in F2 progenies of crosses between 'GhineseSpring' monosomics and 'Fengkang 2'

Progeny formonosomics

lA

IBID2A2B2D3A3B3D4A4B4D5A5B5D6A6B6D7A7B7DTotal (exc. 5B)Disomic

Total numberof plants

46

44

49

41

33

49

50

42

49

46

47

47

4442

51

33

48

4944

3946

897199

ObservedR

35

33

39

35

28

40

35

34

39

33

39

39

38

40

42

28

40

36

352835

711

151

ratioS

11

11

10

6

5

9

15

8

1013

8

86

2

9

58

13

9

11

11

186

48

(3 :1)

0.000.030.331.831.220.820.430.510.330.121.201.20

2.46

8.13-- =

1.11

1.22

1.36

0.01

0.27

0.08

0.00

8.47**

0.04

P

0.865

1.000

0.458

0.125

0.1910.284

0.414

0.373

0.458

0.610

0.207

0.207

0.0820.002

0.2250.1910.1820.8050.4860.6440.8650.0030.775

Monosomic Analyses of Yellow and Leaf Rust Genes in Wheat 155

Table 2. Segregation for resistance to leaf rust race GL38 in F2 progenies of crosses between 'Ghinese Spring'monosomics and 'Fengkang 2'

Progeny formonosomics

Total numberof plants

Observed ratioR S ( 3 : 1 )

lAIBID2A2B2D3A3B3D4A4B4D5A5B5D6A6B6D7A7B7DTotal (exc. 5A)Disomic

474549393349494146444647424050394749434646

895196

333335332531383130283738403042343832303433

665147

14121468

1811101616992

10859

17131213

23049

0.350.010.171.440.013.000.060.011.862.460.460.578.13='-='-0.031.712.470.571.970.380.000.120.200.01

0.4480.7960.5640.1660.9200.0580.6800.9280.1250.0820.3950.3540.0021.0000.1420.0790.3540.1170.4280.8650.6100.6291.000

tion fits well the ratio of 3 : 1 ( ^ = 0.04).Thus, the resistance of Tengkang 2' was con-trolled by a single dominant gene. Among 21monosomic F2 populations, all fit well the ratioof 3 resistant to 1 susceptible except chromo-some 5B's which was clearly different {^ =8.13), indicating that the resistance gene waslocated on chromosome 5B. The pooled resultsfor the 20 non-critical chromosomes deviatedsignificantly from the 3 : 1 ratio expected for asingle gene segregation, and the lack ofheterogeneity {x^ = 8.47) indicated a consis-tent slight excess of resistant segregates. Seed-lings displaying intermediate reactions werenot progeny tested, so it is possible that someof these should have been included in thesusceptible class.

Leaf rust: When infected with leaf rust cultureCL38, Tengkang 2' produced infection typeO;, 'Chinese Spring' 4, and the disomc Fi 0;.

Segregation in the disomic F2 segregatingpopulation was best explained on the basis ofone dominant gene for resistance {)^ = 0.01,Table 2). Segregation of monosomic F2 plantsfor reaction to CL38 was also best explainedon the basis of one dominant gene for resist-ance. Only the results for monosomic 5Ashowed significant deviation from the post-ulated 3 resistant : 1 susceptible ratio, and theapproximate 97 resistant : 3 susceptible ratioobtained in this instance was consistent withthe possibility that the dominant gene waslocated on this chromosome. The pooled re-sults for 20 non-critical crosses showed anexcellent fit to the postulated 3 : 1 ratio, andthe results were not heterogeneous (^ = 0.20).

Our results indicated that the gene for re-sistance to yellow rust race CY25 is locatedon chromosome 5B in Tengkang 2'.Chromosomal location of all 14 yellow rust

156 JIAZHI et al., Monosomic Analyses of Yellow and Leaf Rust Genes in Wheat

resistance genes except Yr3 and Yr4 are known(MCINTOSH 1988), and none are reported onchromosome 5B. Therefore, the resistancegene carried by 'Fengkang 2' is likely to be anew gene.

Of the 34 leaf rust genes identified up to1988, no genes were located on chromosome5A (MCINTOSH, 1988). Consequently, thedominant gene for leaf rust resistance carriedby 'Fengkang 2' is probably new. 'Fengkang 2'has been used in winter wheat breeding pro-grams in China because of its reliability andhigh yield potential, as well as its resistance todisease. The pedigree of 'Fengkang 2' suggeststhat its yellow rust and leaf rust resistant geneson chromosome 5B and 5A, respectively,might be derived from 'Youmanbai 4', a cul-tivar resistant to yellow rust and leaf rust whenit was released.

Zusammenfassung

Monosomenanalyse von Genen fiir Re-sistenz gegen Gelb- und Braunrost bei derWinterw'eizensorte Tengkang 2'

Anhand einer Serie von 'Chinese Spring'-Monosomenlinien wurden Gene fiir Rostresi-stenz in der von der Chinese Academy ofAgricultural Sciences entwickelten Winter-weizensorte 'Fengkang 2' lokalisiert. Die Re-sistenz gegen die Gelbrostrasse CY25 wurdedurch ein dominantes Gen auf Chromosom 5Bbewirkt. Die Resistenz gegen die Braunros-

trasse CL38 konnte ebenfalls auf ein domi-nantes Gen zuriickgefiihrt werden, das aufdem Chromosom 5A von 'Fengkang 2' hegt.Hochstwahrscheinlich handelt es sich um zweibisher unbekannte, neue Gene.

ReferencesMCINTOSH, R. A., 1988: Catalogue of gene symbols

for wheat. In: T. E. MiLLER and R. M. D.KOEBNER (eds.), 7th International Wheat GeneticsSymposium, Gambridge, England, 1273—1281.Inst. Plant Sci. Res., Gambridge.

PANG, J., R. SUN, and Z. YANG, 1991: Monosomicanalysis of gene for resistance to yellow rust inwinter wheat cultivar Beijing 837. Gereal Rusts andPowdery Mildew Bulletin 19, 17—19.

SHEN, K., Z . YANG, X. WANG, and W. SHU, 1991:

Studies on the identification of chromosome loca-tion of wheat resistant genes with monosomicanalysis. Acta Agric. Univ. Pekinesis 17, 31—35.

SHU, W . , K. SHEN, T . YANG, and X. ZHENG, 1990:

A monosomic analysis of the rust resistant gene ofwheat varieties 'Luqiyu' and 'Yantar'. Acta Agron.Sinica 16, 289—297.

STAKMAN, E . G., D . M . STEWART, and W. Q.

LOEGERING, 1962: Identification of PhysiologicalRaces of Puccinia graminis tritid. Publ. E617, US-DA, ARS.

XIN, Z. , 1984: Analysis of stripe rust resistant genesof winter wheat cultivar 'Fengkang 13'. Acta Ag-ron. Sinica 10, 217—222.

YANG, H . , and L. Wu, 1990: Analysis ofpathogenicity and virulence factors of Ghineseraces of Puccinia striiformis tritid. Acta Phytopath.Sinica 20, 213—217.