| Location of genes for resistance to stem rust race
126-Anz-1 in four varieties of wheat C.J. DRISCOLL1 and E.P. BAKER Department of Agriculture, University of Sydney, Australia The genes for resistance to wheat stem rust (Puccinia graminis tritici ERIKSS.), race 126-Anz-1, of the four varieties of common wheat (Triticum aestivum L.), Eureka W 13252, Kenya W 744, Gabo W 1422 and Yalta W 1373, have been located as to specific chromosome by use of the Chinese Spring monosomic series. The stem rust reaction types of the four varieties, nomal Chinese Spring, the F1's involving each of the four varieties x Chinese Spring and the resultant F2's, as shown in Table 1, conform with those described by STAKMAN, LEVINE and LOEGERING (1944). 1. Eureka All F2 families, except that involving chomosome 2D, segregated in conformance with a 3 resistant (res.) : 1 susceptible (sus.) ratio. That involving 2D segregated 64 res. : 7 sus. identifying 2D as the bearer of the single dominant gene for resistance. This gene is either Sr6 according to KNOTT'S gene classification or possibly an allele of Sr6 (WATSON and LUIG, 1963). Evidence for allelism is based on differential reaction types under altered environmental conditions of certain varieties carrying a gene at the Sr6 locus (WATSON and LUIG, 1961; WATSON, pers. comm.). 2. Kenya 744 The F2 family involving chomosome 2A segregated 53 res. : 6 sus., whereas all other twenty F2 families segregated in conformance with 3 res. : 1 sus. This identifies 2A as the bearer of the single dominant gene for resistance. This gene is Sr9b (GREEN et al., 1960). 3. Gabo and Yalta Excluding chromosome 6B, the ratios of res. : sus. of the Gabo F2 families ranged from 1.3 : 1 to 3.3 : 1, whereas those of the Yalta F2 families ranged from 0.6 : 1 to 4.1 : 1. The F2 families involving chomosome 6B segregated 77 res. : 8 sus. (i.e., 9.6 : 1) and 210 res. : 11 sus. (19.1 : 1) with Gabo and Yalta respectively. |
| 1 Present address: Department of Botany, School of Biological Sciences,
Univesity of New South Wales, Kensington, New South Wales, Australia 2 W numbers refer to the varietal number in the University of Sydney Wheat Accession Register |
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