Identifying Quantitative Trait Loci for Economic Traits in an Elite Soft Red Winter Wheat Population

Abstract

Genotyping‐by‐sequencing (GBS), reduces genotyping costs and allows breeders to genotype large populations with thousands of markers. Genome‐wide association studies with GBS markers can be used to identify quantitative trait loci (QTL) for important traits in elite populations of soft red winter wheat (SRWW; Triticum aestivum L.). Our objective was to identify potential QTL for grain yield (GY), Fusarium head blight resistance (FHB), flour yield (FY), and softness equivalence (SE) in a set of 470 elite SWRR wheat lines that were genotyped with 33,169 GBS markers and phenotyped in multiple environments. For all traits, we found lines that were phenotypically superior to the elite checks. We identified four FHB QTL, nine QTL for quality, and 14 QTL for with R2 values ranging from 1.6 to 3.5%. The QTL with the largest effect for FHB resistance reduced disease by 1.76%. For quality, the largest‐effect QTL increased FY and SE by 0.37 and 0.67%, respectively. For GY the QTL with the largest effect in Wooster, OH, increased GY by 129.6 kg ha−1, for northwest Ohio, the largest‐effect QTL increased GY by 67.2 kg ha−1, and the largest‐effect QTL for GY over all environments increased GY by 48.8 kg ha−1. While marker‐assisted selection (MAS) for these QTL could be used to improve these traits, the preponderance of genetic variation appeared to be controlled by genes with small effect, suggesting that MAS should be used as a supplement to genomic selection.

Quantitative trait loci associated with soft wheat quality in a cross of good by moderate quality parents

“…Heritability of the ten quality traits ranged from 0.67 to 0.90 (Table 4). These results agreed with previous studies in soft winter wheat genotypes adapted to the southern or northern US (Baezinger et al, 1985;Basset et al, 1989;Souza et al, 2002;Smith et al, 2011;Cabrera et al, 2015;Hoffstetter et al, 2016).…”

“…The coincident QTL often corresponded to trait correlations (Table 3). The water absorption capacity traits AWRC, WA, SU, and SO were all positively correlated as has been reported by others for soft wheat (Guttieri & Souza, 2003;Ram et al, 2005;Smith et al, 2011;Cabrera et al, 2015;Hoffstetter et al, 2016). There were 10 marker-trait associations from four regions for these traits and only one was not coincident with another.…”

“…Heritability for all traits ranged from 0.67 to 0.90 (Table 4). Others have reported similar heritability values for soft wheat quality traits (Guttieri & Souza, 2003;Smith et al, 2011;Cabrera et al, 2015;Hoffstetter et al, 2016).…”

“…Loci associated with water absorption capacity have been identified in hard wheat (Mansur et al, 1990). Similarly, loci influencing FP, kernel hardness, and TW have been mapped (Mattern et al, 1973;Blanco et al, 1996;Sourdille et al, 1996: Prasad et al, 1999Perretant et al, 2000; about the heritability of SRCs in soft wheat have shown high heritability (Guttieri & Souza, 2003;Smith et al, 2011;Cabrera et al, 2015;Hoffstetter et al, 2016). Common QTLs for AWRC and damaged starch were observed in a hard x soft population on chromosome 4DL (Campbell et al, 2001).…”

“…Cabrera also presented evidence that QTL located on 1B and 2B affected SRWW quality even in the absence of the translocations. Hoffstetter et al (2016) conducted an association analysis in SRWW and reported nine QTL though the r 2 values were small (0.018 to 0.036).…”