Phenotypic selection of wheat genotypes for drought stress tolerance

Drought stress is the leading constraint of wheat production and yield reduction induced by drought surpasses decreases from all the other causes. Moreover, wheat is more sensitive to drought stress when imposed at anthesis stage. In this study, attempts were made to evaluate the effectiveness of seedling traits as selection criteria for drought tolerant genotypes and highlights losses in yield due to drought particularly on anthesis stage. One hundred and fifty wheat genotypes and 65 F₁ generations of selected parents were assessed in separate experiments for various seedling traits i.e., root length, shoot length and root/shoot ratio) and yield attributes i.e., spike length, number of spikelets per spike, number of grains per spike, grain weight per spike, 1000-grain weight and grain yield per plant under controlled and drought stress. Owing to the diverse genetic background of germplasm, genotypes exhibited variation in their response towards drought. Correlation analysis depicted the existence of significant relationship between seedling and yield related traits under drought stress. Significant decrease in seedling traits and yield was observed with the onset of drought stress. Genotypes Chakwal-86, Manthar-2003, Aas-11, Chakwal-50, Miraj-2008, 9488, 9859, 9805, 9637 and 9512 showed tolerance to drought in terms of seedling growth and yield. Genetic studies divulge the existence of non-additive genes for all the characters excluding spike length which exhibited additive gene action. Cross combinations 9633 x Chakwal-86, Faisalabad-08 x Chakwal-50, 9507 x 9805, 9805 x 9633, 9507 x Manthar-03 observed high yield under drought conditions. These crosses can be exploited in various developmental programs aimed for drought-hit areas of Pakistan. Selection based on seedling traits was found effective for selection of drought-tolerant wheat genotypes at anthesis. Mass selection of wheat crosses at anthesis stage may be an effective option to cope with the drought stress owing to their non-additive gene action.