Response to Direct and Indirect Selection to Improve Grain Yield of Durum Wheat

This study was conducted over three growing seasons (2020/21, 2021/22, and 2022/23) at Shandaweel Agric. Res. Stat., Agri. Res. Cent., Egypt. The aim of this research was to evaluate the effect of direct selection for grain yield plant-1 and indirect selection for each of spike number plant-1 and 100-kernel weight to improve grain yield and produce new high yielding durum wheat lines. Two pedigree selection cycles were applied from the F2 to F4 generations, focusing on grain yield plant-1, spike number plant-1‎, and 100-kernel weight, under optimal growing conditions. The findings revealed that the phenotypic variance marginally exceeded the genotypic variance, and both generally declined from (F2) to (F4) generation. Following two pedigree selection cycles, broad sense and realized heritability estimates for grain yield plant-1 attained 78.73 and 48.63%, respectively. Similarly, the heritability estimates were 97.29% and 46.14% for the spike number plant-1 ‎ and 91.51% and 61.90% for the weight of 100 kernels. The observed gain following two direct pedigree selection cycles were 11.12 and 8.45% for grain yield plant-1, 5.23 and 2.11% with indirect selection for spike number plant-1 and 7.57 and 10.39% with indirect selection for 100-kernel weight in comparison with the bulk sample and the superior parent, respectively.