Molecular identification and validation of four stable QTL for adult-plant resistance to powdery mildew in Chinese wheat cultivar Bainong 64

Abstract

Wheat powdery mildew, caused by Blumeria graminis f. sp tritici (Bgt), is a devastating fungal disease. Seedlings of Chinese winter wheat cultivar Bainong 64 are susceptible to Bgt but adult plants have maintained slow-mildewing resistance since it was released in 1996. A population of 171 recombinant inbred lines (RILs) developed from cross Jingshuang 16/Bainong 64 (JS16/BN64) was used to dissect genetic components of powdery mildew resistance. A genetic map comprising 5,383 polymorphic markers was constructed using the 15K SNP chip and kompetitive allele-speci c PCR (KASP) markers.Composite interval mapping identi ed four stable QTL on chromosome arms 1DL, 2BS, 2DL, and 6BL in all ve environments and their favorable alleles were inherited from BN64. The QTL accounted for 8.3%, 13.8%, 14.4%, and 9.0% of the total phenotypic variances in maximum, respectively. QPmjbr.caas-1DL,situated about 22 Mb from centromere, is probably a new QTL. QPmjbr.caas-2DL located near the end of arm 2DL. Using genetic maps populated with KASP markers, QPmjbr.caas-2BS and QPmjbr.caas-6BL were ne mapped to a 1.8 cM genetic intervals spanning 13.6 Mb (76.0-89.6 Mb) and 1.7 cM and 4.9 Mb (659.9-664.8 Mb), respectively. The four QTL were all independent of stripe rust and leaf rust resistance and were validated for slow-mildewing in another RIL population related to BN64 and a cultivar panel using representative KASP markers spanning each QTL. Since BN64 has been a leading cultivar and an important breeding parent, the QTL and markers reported in this study will be useful for markerassisted selection of slow-mildewing resistance. Key MessageFour stable QTL for slow-mildewing were identi ed on chromosome arms 1DL, 2BS, 2DL and 6BL in the widely grown Chinese wheat cultivar Bainong 64. These QTL had no effect on response to stripe rust or leaf rust.

Effect of genotyping errors on linkage map construction based on repeated chip analysis of two recombinant inbred line populations in wheat (Triticum aestivum L.)

“…The two wheat populations used in this study were YZ F 6 RILs and JB F 6 RILs, which had been reported in Li et al [ 30 ] and Xu et al [ 31 ], respectively. The parents and 193 progenies in the YZ population (denoted as YZ1 to YZ193) were planted at Beijing and Shijiazhuang (Hebei Province) in 2011–2012 cropping season, and Gaoyi (Hebei Province) and Xinxiang (Henan Province) in 2019–2020 cropping season [ 30 ].…”

“…The parents and 193 progenies in the YZ population (denoted as YZ1 to YZ193) were planted at Beijing and Shijiazhuang (Hebei Province) in 2011–2012 cropping season, and Gaoyi (Hebei Province) and Xinxiang (Henan Province) in 2019–2020 cropping season [ 30 ]. The parents and 181 progenies in the JB population (denoted as JB1 to JB181) were planted at Beijing and Gaoyi (Hebei Province) in 2019–2020 cropping season [ 31 ]. The samples for genotyping were harvested in Gaoyi 2019–2020 cropping season for both populations.…”