Growth and yield component analysis of durum wheat as an index of selection to terminal moisture stress

Durum wheat (Triticum turgidum L.) yields in Ethiopia are primarily limited by water deficiency. Field and greenhouse studies were conducted using fiv e cultivars (Tob-2, DZ, Boohai, Omrabi-5, and Po) under moisture stress dur ing the terminal period of growth and non-stress conditions to evaluate gro wth and some components of yield. Analysis of the relative growth rate (RGR ) and its components showed significant differences between varieties. Drou ght-tolerant cultivars had a high RGR during favourable periods of the grow ing season and a low RGR during moisture stress. Path-coefficient analysis revealed that longer vegetative periods were associated with reduced grain- filling periods (GFP) and negatively associated with drought resistance. Th e direct effect of number of spikes m(-2) (Sm-2) on grain yield (GY) was po sitive and significant. However, the indirect effect via kernels per spike (K/S) and kernel weight (KW) was negative. Gain-filling period had a strong influence on GY via KW, Kernels per spike had the largest direct effect on GY, Variation in drought susceptibility index among cultivars was signific ant. This study concluded that lower RGR, longer GFP, increased number of K /S, and limited Sm-2 can be used as selection criteria under water-limited environments for drought resistance.