QTL CLUSTER FOR GRAIN SIZE AND PHENOLOGY TRAITS REVEAL CANDIDATE GENES INVOLVED IN GRAIN YIELD OF DURUM WHEAT

Grain yield (YLD) reflects the combination of thousand kernels weight (TKW) and grain number per area. TKW is mainly and tightly underpinned by grain length (GL), grain width (GW) and area (AREA). YLD can be maximized by growing varieties which heading time (HT) allows the crop to avoid stresses during grain-filling phase. HD is a critical stage that marks the transition into the grain-filling period, during which grain weight is defined. In the present study, a high-density genetic linkage map based on iSelect 90K SNP markers was realized using the durum wheat Liberdur x Anco Marzio recombinant inbred line (RIL) population that was evaluated to detect QTL and candidate genes controlling YLD, GL, GW, AREA, HT and plant height (PH). The two parents showed significant differences for HT, PH, AREA in all three seasons, and for TKW, GL and GW in two trials. The parental Anco Marzio has generally larger grains compared to those of Liberdur, which were narrower. High heritability values, exceeding 0.55, were found for HT, GL and AREA while TKW heritability values ranged from 0.45 to 0.72.