A multidisciplinary approach for dissecting qtl controlling high-yield and drought tolerance-related traits in durum wheat

Abstract

Durum wheat (Triticum turgidum ssp. durum) is an economically and nutritionally important cereal crop in the Mediterranean region and itsproduction is largely influenced by environmentalstresses, such as drought, salinity, heat and nutrient deficiency.The objective of this study was to dissect quantitative trait loci (QTL) controlling grain yield,yield componentsand drought tolerancein durum.Amolecular genetic linkage map for F2 durum mapping population derived from an intraspecific cross between Baniswif-1 x Sohag-2was constructed using 114DNA markers (9 SSRs, 14 SCoTs,90 AFLPs and 1 RAPDs) distributedover the 14linkage groups and spanning 2040.9 cM of the durum wheat genome. The size of linkage groups varied greatly from 6.8cM for LG11 to 317.5cM for LG4 with an average length of 145.8cM. Based on the usedanchor SSR markers, only eight linkage groups were assigned to chromosomes,where LG1, LG3, LG5, LG6, LG7, LG9, LG13 and LG14 were assigned to chromosomes 1B, 3B, 5B, 6A, 6B, 7A, 3A and 2B,respectively. Single point analysis was used to identify genomic regions controlling eleven morpho-physiologicaltraitsrelated to grain yield, yield components and drought tolerance. A total of 74 QTL were identified for the eleven traits on all linkage groups except (LG10 and LG11).These included 3 QTLfor root length (RL), 11 QTLfor plant height (PH), 7 QTLforspike length (SL), 3 QTLfor number of branches/plant (NBP), 3 QTLfor number of spike/plant (NSP), 8 QTLfor number of spikelets/spike (NSS), 15 QTLfor number of kernel/spike (NKS), 10 QTLfor thousand-kernel weight (TKW), 4 QTLfor fresh weight (FW), 5QTLfor dry weight (DW) and 5 QTLfor total amino acids (TAA). This work represents the first genetic linkage map for durum wheat population derived from an intraspecific cross between ̳Baniswif-1‘ and ̳Sohag-2‘ showing chromosomal regions associated with11 morpho-physiological traits related to grain yield, yield components and drought tolerance in durum wheat