Abstract:

Powdery mildew, caused by Blumeria graminis f. sp. tritici, is a major wheat disease in China. Use of adult-plant resistance is an effective method to develop wheat cultivars with durable resistance to powdery mildew. In the present study, a total of 313 SSR and 37 RFLP markers were used to map QTL for adult-plant resistance to powdery mildew in a DH population with 107 families derived from the cross Fukuho-komugi × Oligoculm. Field trials were conducted in Beijing in 2003－2004 crop season, and in Anyang, Henan Province in 2003－2004 and 2004－2005 crop seasons, respectively. The DH families were planted in a randomized complete block design with 3 replicates. Artificial inoculation was carried out in Beijing with highly virulent isolate E20 of Blumeria graminis f. sp. tritici and the powdery mildew severity on penultimate leaf was evaluated for 5 times. The maximum disease severity on penultimate leaf was scored in Anyang under natural inoculation around May 18, 2004 and 2005. Linkage analysis indicated that the genetic map consisting of 313 SSR and 37 RFLP markers covered 21 wheat linkage group with a total genetic distance of 3 101 cM. With the method of composite interval mapping (CIM), 4 QTLs for adult-plant resistance to powdery mildew were detected on chromosome 1A，2B，4B and 7D, explaining 13.6%，6.6%，8.9% and 12.7% of phenotypic variance, respectively. Three QTLs on chromosome 1A, 2B, and 7D were derived from the female parent Fukuho-komugi, while the one on chromosome 4B was from the male Oligoculm. The QTL on chromosome 1A showed high genetic effect for powdery mildew resistance across two environments. These results are essential for marker-assisted selection for improving powdery mildew resistance in wheat breeding programs.

Key words: Common wheat, Powdery mildew, Adult-plant resistance, Quantitative trait loci (QTL)