Genetic Assessment of Yield and Yield Components in a Highly Structured Jordanian Durum Wheat Landrace Germplasm Under Different Semi-Arid Climatic Conditions

Durum wheat (Triticum durum L.) is grown in the Mediterranean region under variable environmental conditions and stresses. In this study we evaluate 150 Jordanian landraces for yield and 13 yield components traits in three locations in Jordan (Rabba, Maru and Mushaqar) for three seasons under rainfed conditions. The study aims to understand the G×E interactions and stability paramters and to identify QTLs related to yield and yield components. The accessions were planted in augmented designs and genotyped with the using the Illumina Infinium iSelect 90,000 SNP wheat array. The nine environments were divided into low yielding environments (LYE) comprising all seasons in Rabba location and Mushaqar in 2011, while the rest were considered as high yielding environments (HYE). The wheat accessions exhibited significant variation for all the traits studied with high genotypic coefficient of variation (CV %) except for days to heading and days to maturity. Based on GGE biplot analysis of grain yield (GY), wheat accessions were divided into six groups in Rabbah and Maru and eight groups in Mushaqar. Accessions #18, #118, and #10 gave the highest GY under LYE, while accessions #131, #109 and #70 were the best under HYE. Accessions 137, 132 and 148 were high yield and have high stability performance under the nine environments. The GWAS analysis revealed two important locations associated with multiple traits including GY on 1BL and 6AL. Moreover, two homologous QTLs on 6AS and 6BS related to kernel number and weight per spike were reported in the regions of the homologues wheat grain development genes TaGW2-6A and TaGW2-6B. Utilizing Jordanian wheat landraces will effectively improve and adapt the current wheat cultivars for the different environmental stresses.