Abstract only

The Chinese wheat cv. Chuanyu 16 has good APR to stripe rust. Two populations, each with 140 RILs, were developed by SSD from Chuanyu 16/Chuanyu 12 and Chuanyu 16/Chuanmai 32, and used for QTL mapping. Field trials were conducted in Chengdu and Yaan from 2005 to 2008, providing stripe rust reaction data for six environments; 731 SSR markers were screened through BSA. Three QTLs for stripe rust resistance, QYr.caas-1BL.1, QYr.caas-1BL.2 and QYr.caas-2AS,in Chuanyu 16, detected in Chuanyu 16/Chuanyu 12 by ICIM, explained 6.0 - 12.8%, 4.5 - 5.8%and 14.9 - 43.0%, respectively, of the phenotypic variance across environments. One digenic epistatic QTL between QYr.caas-1BL.2 and QYr.caas-2AS explained 4.3 - 10.4% of the phenotypic variance. QYr.caas-2AS was also detected in Chuanmai 32/Chuanyu 16, explaining 27.9 - 57.2% of the phenotypic variance across six environments. This QTL showed a major effect against stripe rust, and was located in a similar position to Yr17. Specific markers indicated the presence of a segment from chromosome 2N of Triticum ventricosum that carries Yr17. Despite the lack of evidence for Yr17 in Chuanyu 16 based on pedigree, and inconsistencies in stripe rust response relative to a near-isogenic reference stock with the gene, we concluded that QYr.caas-2AS is Yr17. QYr.caas-1BL.1 and QYr.caas-1BL.2 had relatively minor effects on APR to stripe rust. QYr.caas-1BL.1 is probably a new gene for stripe rust APR.

Global Wheat Program

English

Lucia Segura

INT2411

CIMMYT Staff Publications Collection