Relationships of Genes for Reaction to Stem Rust from ‘Marquis’ and ‘Reliance’ Wheat to Other Sr Genes1
- N. D. Williams and
- Hossein Kaveh2
We determined the allelic and linkage relations among genes for stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. & E. Henn.) resistance in wheat lines designated Mq-A, Mq-B, Mq-C, and Rl-B-1, which were derived from crosses of ‘Little Club’ with ‘Marquis’ or ‘Reliance’ wheat (Triticum aestivum L. em Thell.). The four derived lines were crossed with 14 tester lines having genes for resistance known to be located on specific chromosomes of ‘Hope,’ ‘Thatcher,’ ‘Red Egyptian,’ ‘Timstein,’ and an atypical Marquis selection. All F1's were selfed, and certain F1's were testcrossed with Little Club. The F2's and testcross-F1's were tested for seedling reaction to races 111, 121, or 29 of P. graminis f. sp. tritici. Segregation for resistant and susceptible seedlings in the F2 and testcross populations indicated nonallelism, and absence of segregation indicated allelism or close linkage. The gene for resistance in Mq-A was the same as, allelic to, or closely linked with Sr18 on chromosome 1D of Hope. Sr19 in Mq-B was linked with Sr9a on chromosome 2B of Red Egyptian (p = 0.24 ± 0.03) and with Sr9d on 2B of Hope (p = 0.24 ± 0.02). A gene in Rl-B-1 for resistance to culture 111-SS2 of race 111 was the same as, allelic to, or closely linked with Sr16 on chromosome 2B of Thatcher. One of two genes in substitution line Chinese Spring(Mq-2B) was Sr16. A gene in Rl-B-1 for resistance to culture GB121-1 of race 121 was the same as, allelic to, or closely linked with Sr5 on chromosome 6D of Thatcher. Sr20 from Mq-C segregated independently of the other genes for resistance.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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