Quantitative Trait Loci for Grain Yield and Adaptation of Durum Wheat (<i>Triticum durum</i> Desf.) Across a Wide Range of Water Availability

TLDR

Grain yield is a major breeding target for durum wheat, especially in drought‑prone regions. The study investigates the genetic basis of grain yield, heading date, and plant height in 249 recombinant inbred lines across 16 environments with varying water availability. The authors evaluated 249 recombinant inbred lines in 16 environments (10 rainfed, 6 irrigated) spanning a wide range of water availability and grain yield. The study identified 16 QTL for grain yield, with two major loci on chromosomes 2BL and 3BS explaining 21.5 % and 13.8 % of variation across 8 and 7 environments, respectively, and found extensive overlap of these loci with plant‑height QTL but not heading‑date QTL, while PH QTL were located on 1BS, 3AL, and 7AS, HD QTL on 2AS, 2BL, and 7BS had limited or no grain‑yield effects, and notable epistasis between the 2BL and 3BS loci was observed for both PH and GY.

Abstract

Abstract Grain yield is a major goal for the improvement of durum wheat, particularly in drought-prone areas. In this study, the genetic basis of grain yield (GY), heading date (HD), and plant height (PH) was investigated in a durum wheat population of 249 recombinant inbred lines evaluated in 16 environments (10 rainfed and 6 irrigated) characterized by a broad range of water availability and GY (from 5.6 to 58.8 q ha−1). Among the 16 quantitative trait loci (QTL) that affected GY, two major QTL on chromosomes 2BL and 3BS showed significant effects in 8 and 7 environments, with R2 values of 21.5 and 13.8% (mean data of all 16 environments), respectively. In both cases, extensive overlap was observed between the LOD profiles of GY and PH, but not with those for HD. QTL specific for PH were identified on chromosomes 1BS, 3AL, and 7AS. Additionally, three major QTL for HD on chromosomes 2AS, 2BL, and 7BS showed limited or no effects on GY. For both PH and GY, notable epistasis between the chromosome 2BL and 3BS QTL was detected across several environments.