Genetic Attributes and Correlation Studies for Important Traits in Wheat Under Irrigated and Rainfed Conditions

Development of new and high yielding cultivars is the main goal of plant breeders. This research was conducted to determine genetic diversity, heritability, genetic advance and correlations among various traits in wheat advance lines under rainfed and irrigated conditions. A set of 20 wheat genotypes was evaluated in a randomized complete block design (RCBD) with three replications at The University of Agriculture, Peshawar, during 2020–21. Pooled analysis showed highly significant diversity among genotypes for all the studied parameters. Genotypes by environment (G × E) interaction was also highly significant for all the studied traits except spike length and grain weight spike⁻¹. The best performing genotype for yield related attributes was G202 for spikes m⁻² (385.0), grain weight spike⁻¹ (3.2 g), grains spike⁻¹ (68.0 g) and G149 for 1000-grain weight (55.1 g) under irrigated condition, while under rainfed condition the best genotype was G131 for spikes m⁻² (303.3), grain weight spike⁻¹ (2.5 g) and grains spike⁻¹ (59.7) and genotype G148 for 1000-grain weight (51.1 g). High heritability and expected genetic advance were observed for all the traits except plant height, spike length and grain weight spike⁻¹ which showed low to moderate broad sense heritability under irrigated and rainfed conditions. Grain yield showed highly significant positive genotypic and phenotypic correlations under irrigated condition with spikelets spike⁻¹ (r_g = 0.80**, r_p = 0.60**), grains spike⁻¹ (r_g = 0.83**, r_p = 0.59**), grain weight spike⁻¹ (r_g = 0.99**, r_p = 0.62**) and 1000-grain weight (r_g = 0.81**, r_p = 0.59**). Similarly, the genotypic and phenotypic correlations of grain yield were highly significant and positive with spikes m⁻² (r_g = 0.71**, r_p = 0.69**), spikelets spike⁻¹ (r_g = 0.64**, r_p = 0.59**), biological yield (r_g = 0.74**, r_p = 0.66**) and harvest index (r_g = 0.83**, r_p = 0.72**) under rainfed condition. These characters having high correlations with grain yield could be utilized for development of high yielding wheat cultivars. The promising genotypes under irrigated condition were G202, PS-15 and G106 while under rainfed condition the promising genotypes were G131, G148 and G116. Thus, these genotypes could be used in the future breeding programs.