Effects of Drought Stress on Morphological, Physiological Traits of Wheat (Triticum Aestivum L.) Cultivars in Pakistan
Drought is major abiotic stress affecting the morphological, physiological and biochemical processes. Genetic improvement for drought tolerance in wheat could be possible to develop new genotypes through conventional breeding. To investigate drought resistance under water stress condition, a trial was conducted in spilt block design, using eight genotypes, i.e., Inqlab-91, PBGST-03, PBGST-01, PBGST-02, SKD-1, Hero, Sundar, and Sassuai along with two treatments (non-stress and water stress at anthesis stage). The experiment was carried out in the field of Botanical Garden, Sindh Agriculture University, Tandojam, Sindh, Pakistan. A significant reduction appeared in morphological traits at the anthesis stage due to the reduction of irrigation. The mean squares from analysis of variance due to genotypes, treatment, and treatments x genotypes interactions were significant at P ≤0.05 for all the traits, indicating that the genotypes performed variably under stress conditions. Based on the mean performance, among the cultivars; Sassui revealed better performance for grains spike-1and seed index (1000g wt) under normal irrigations, whereas under stress at anthesis, PBGST-02 showed higher grain yield plant-1, maximum productive tillers, and spikelets spike-1. Hence, such genotypes could be suggested to be tolerant under water stress. The correlation coefficient showed that spike length, spikelets spike-1and grains spike1 possessed positive and significant association with grain yield plant-1 at normal conditions. Seed index (1000gwt.) and harvest index (%) exhibited a positive but non-significant correlation. However, these all traits revealed a positive significant association under stress conditions with grain yield plant-1. Based on these results, the genotypes PBGST-03, Sassuai and SKD-1 are the potential genotypes that could be used in the water-deficient condition.