Quantitative Trait Loci Mapping for Adult-Plant Resistance to Powdery Mildew in Bread Wheat

Abstract

Powdery mildew, caused by Blumeria graminis f. sp. tritici, is a major disease to wheat (Triticum aestivum) worldwide. Use of adult-plant resistance (APR) is an effective method to develop wheat cultivars with durable resistance to powdery mildew. In the present study, 432 molecular markers were used to map quantitative trait loci (QTL) for APR to powdery mildew in a doubled haploid (DH) population with 107 lines derived from the cross Fukuho-komugi x Oligoculm. Field trials were conducted in Beijing and Anyang, China during 2003-2004 and 2004-2005 cropping seasons, respectively. The DH lines were planted in a randomized complete block design with three replicates. Artificial inoculation was carried out in Beijing with highly virulent isolate E20 of B. graminis f. sp. tritici and the powdery mildew severity on penultimate leaf was evaluated four times, and the maximum disease severity (MDS) on penultimate leaf was investigated in Anyang under natural inoculation in May 2004 and 2005. The heritability of resistance to powdery mildew for MDS in 2 years and two locations ranged from 0.82 to 0.93, while the heritability for area under the disease progress curve was between 0.84 and 0.91. With the method of composite interval mapping, four QTL for APR to powdery mildew were detected on chromosomes 1AS, 2BL, 4BL, and 7DS, explaining 5.7 to 26.6% of the phenotypic variance. Three QTL on chromosomes 1AS, 2BL, and 7DS were derived from the female, Fukuho-komugi, while the one on chromosome 4BL was from the male, Oligoculm. The QTL on chromosome 1AS showed high genetic effect on powdery mildew resistance, accounting for 19.5 to 26.6% of phenotypic variance across two environments. The QTL on 7DS associated with the locus Lr34/Yr18, flanked by microsatellite Xgwm295.1 and Ltn (leaf tip necrosis). These results will benefit for improving powdery mildew resistance in wheat breeding programs.

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“…The number of powdery mildew resistance QTL detected in the RE714 9 'Hardi' RIL population is lower than what was obtained by Keller et al (1999) (18 QTL with a LOD score higher than 3.0) or by Bougot et al (2006) (11 QTL, LOD [ 3.2), but is higher than what was obtained by Liang et al (2006) (4 QTL, LOD [ 2.5) or by Börner et al (2002) (3 QTL, LOD [ 3.0) (see Table 5). These differences can be explained by differences in the genetic background of the wheat population analysed leading to differences in polymorphism at powdery mildew resistance QTL and in composition of the powdery mildew population.…”

“…During the past 10 years, several studies on the genetic control of APR to powdery mildew were carried out in several wheat lines, including the Swiss cultivar Forno , the US' cultivar Massey and its derivatives (Liu et al 2001;Tucker et al 2006), the spring variety Opata 85 and the synthetic wheat W7984 (Börner et al 2002), the French breeder lines RE714 (Chantret et al 2001;Mingeot et al 2002) and RE9001 (Bougot et al 2006), the Japanese cultivar Fukuho-komugi (Liang et al 2006), a T. militinae introgression line (Jakobson et al 2006) and the CYMMIT cultivar Saar (Lillemo et al 2008). In these studies, 3-18 QTL were identified, among which between one and three were consistent across environments.…”

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“…Another feature of Lr34 resistance is that it remained genetically inseparable from Yr18 gene, which confers APR. This gene co-segregates with leaf tip necrosis (Ltn1), powdery mildew resistance (Pm8), Barley yellow dwarf virus (Bydv1) genes [48,49]. These multipathogen resistance traits have made the Lr34/Yr18 locus one of the highly valuable regions for disease resistance in wheat [45].…”

Partial resistance to powdery mildew in German spring wheat ‘Naxos’ is based on multiple genes with stable effects in diverse environments

“…The QTL combinations were determined by the closely linked markers gwm33a and UP3B/UP1A for 1AS, gwm626 and wPt-9231 for 6BL, wPt-7299 and barc108 for 7AL, wmc41 and gwm133 for 2DLc, cfd50 and cfd161 for 2DL B e i j i n g 1 1 B e i j i n g 1 0 A n y a n g 1 0 N a n j i n 2006; Liang et al 2006;Mohler et al 2011). At this locus, Liang et al (2006) detected a QTL with resistance from Fukuho-komugi which was derived from the Pm3a carrier Norin 29 and suggested that the adult plant resistance might be a residual effect of Pm3a. Bougot et al (2006) mapped a QTL for powdery mildew resistance at the vernalized seedling stage with resistance conferred by the Pm3g carrier RE9001.…”

“…Several major quantitative trait loci (QTL) for partial resistance have been identified in the North American winter wheats 'Massey' and 'USG3209' (Tucker et al 2007), the Swiss winter wheat 'Forno' (Keller et al 1999), the French winter wheats RE714 (Mingeot et al 2002;Chantret et al 2000) and RE9001 (Bougot et al 2006), the Japanese wheat 'Fukuho-komugi' (Liang et al 2006), in the CIMMYT spring wheats 'Opata 85', W7984 (Börner et al 2002) and Saar (Lillemo et al 2008), in the Chinese cultivars 'Lumai 21' (Lan et al 2010) and 'Bainong 64' (Lan et al 2009), and the Swedish winter wheat cultivar 'Folke' (Lillemo et al 2012). The QTL on 1BL, 2BL and 7DS were the most frequently detected.…”