Abstract

Durum wheat is one of the most important staple food crops grown mainly in the Mediterranean region where its productivity is drastically affected by drought. Detecting the important traits and molecular markers associated with drought and grain yield traits will aid breeders to understand the genetic mechanisms of drought tolerance of durum wheat that will assist in the development of drought tolerant varieties through the use of marker-assisted selection (MAS). The study objectives were to identify putative chromosomes regions affecting grain yield expression under drought conditions. A population of 114 F₈ recombinant inbred lines (RILs), derived by single-seed descent from a cross between "Omrabi 5" (drought tolerant variety) and "Belikh 2" (less drought tolerant), was used for this purpose. Phenotypic data of the RILs and parental lines were measured for 16 traits at Maru Agricultural Research Station (Jordan) for two consecutive seasons; 2006 to 2007 (annual rainfall 268.9 mm) and 2007 to 2008 (annual rainfall 230.6 mm). Marker-trait associations were investigated using a mixed linear model (MLM). A total of 32 simple sequence repeat (SSR) loci were significantly associated with these traits. For phonological traits, 18 markers were associated with morpho-phonological, while 31 markers were associated with yield and its components. Marker alleles from "Omrabi 5" were associated with a positive effect for the majority of traits for yield and its components. Six markers were closely linked with grain yield and these markers could be used for MAS in durum wheat breeding under drought conditions.

Key words: Durum wheat, marker-assisted selection, trait analysis by association, evolution, and linkage (TASSEL), recombinant inbred lines (RILs), simple sequence repeat (SSR), transgressive segregation.