Assessment of genetic diversity and agronomic traits of durum wheat germplasm under drought environment of the northern Great Plains

Abstract

AbstractDurum wheat (Triticum turgidum L. ssp. durum) is an important food crop worldwide. Modern breeding has yielded elite durum wheat cultivars with improved grain yield, end‐use quality, and disease resistance. In this study, we compared 150 breeding lines from the North Dakota State University (NDSU) durum wheat breeding program to 163 durum landraces using a large set of single nucleotide polymorphism (SNP) markers. We found that the genetic diversity of the NDSU durum breeding population was decreased by ∼60% relative to collection of 163 landraces. Selective sweep analysis identified several candidate regions that might have undergone breeding selection. Also in this study, over 260 worldwide durum wheat accessions were evaluated in drought environments of the northern Great Plains for 3 yr, a major growing area of durum wheat in the United States. One line showed significantly higher grain yield than the local elite cultivars. A number of lines showed significantly higher grain yield component traits like seeds per spike and thousand‐kernel weight. Those desirable lines may contain complementary favorable alleles and can possibly be used to improve grain yield under drought stress. Genome‐wide association mapping found no major quantitative trait loci (QTL) but a number of QTL with minor effect for grain yield, which could be explained by grain yield's complex genetic nature, the rare frequency of the novel complementary alleles, and the limited number of environments and replications for phenotypic evaluation in the study. Further QTL mapping using biparental populations derived from the identified desirable lines and elite cultivars may be able to identify the QTL related to grain yield, which can facilitate introgression of the complementary favorable alleles through marker‐assisted selection.