Investigating the Genetic Contribution of Effective Traits in Grain Yield of Durum Wheat under the Normal Irrigation and Drought Stress Conditions at the Terminal Drought

Abstract

The current research has been conducted with 64 F7 recombinant inbred lines durum wheat resulting from crossing of the Shotordandan and Dena along with two parents in an alpha lattice design with two replications in two years (2016–2018) to investigate the genetic contribution of effective traits in grain yield and the relationship between traits and evaluation the susceptibility and tolerance to drought stress. Drought stress led to the decreased grain yield and its components but remobilization and efficiency of remobilization increased. Phenological traits and spike length had the lowest heritability value but the thousand kernel weight had the highest heritability. Frequency distribution of spike length, number of spikes per m2, number of seeds per plant, biological yield and harvest index was normal under two desired conditions and for grain yield under drought stress, indicating quantitative inheritance of these traits. Significant transgressive segregation in the positive direction was observed for yield components such as the number of spikes per square meter, the number of seeds per plant and the thousand kernel weight, as well as remobilization and remobilization efficiency in drought conditions. Grain yield under normal conditions had a positive and significant correlation with the number of spikes per plant and under stress conditions there was a positive and significant correlation with the number of spikes per plant, biological yield and harvest index. Based on drought tolerance and Susceptibility indices, 16 lines from among the recombinant inbred lines along with the Shotordandan parent were determined as tolerant genotypes.