Genetic parameter estimation for yield and related traits in wheat across environments

In wheat-growing regions like Pakistan, late planting is a significant constraint caused by climate variability and cropping system intensity, leading to substantial yield losses.To develop resilient, highyielding varieties, breeders require a deep understanding of genetic variability and the performance of diverse germplasm under both optimal and stress conditions.This study was therefore conducted to estimate genetic parameters and assess the genotype-by-environment interaction for yield and related traits in wheat under normal and late planting scenarios.Seventy wheat genotypes (including six checks) were evaluated under normal and late planting conditions at The University of Agriculture, Peshawar, during 2018-19.The experiment was laid out in an alpha lattice design with two replications.Data were recorded for various morphological and yield-related traits, and genetic parameters such as heritability and genetic advance were estimated.Combined analysis revealed significant genetic variability among genotypes.The genotype-by-environment (G×E) interaction was non-significant for most traits, indicating stable performance across environments for traits like plant height and thousand grain weight; however, significant G×E was observed for tillers per square meter and grains per spike, highlighting their sensitivity to environmental change.Mean grain yield ranged from 775 kg ha⁻¹ (G-29) to 2975 kg ha⁻¹ (G-130).High broad-sense heritability was recorded for days to maturity (93%), while most other traits showed moderate heritability.Genetic advance was moderate to low for most traits, suggesting the role of both additive and non-additive gene action.The study successfully identified elite genotypes with specific adaptive traits.Genotype G-99, which matured earlier under both conditions, is a valuable genetic resource for developing short-duration varieties that can escape terminal heat stress in late-sown environments.Genotype G-130, with its superior yield potential, is a prime candidate for direct cultivation or as a parent in yield enhancement programs.From a scientific perspective, the moderate to high heritability estimates for key traits confirm that selection for these traits can be effective.However, the low genetic advance for grain yield suggests that simple selection methods may be slow, and future breeding efforts should incorporate advanced techniques like marker-assisted selection or genomic selection to accelerate genetic gain.The outputs of this research directly benefit society by identifying climate-resilient germplasm that can help stabilize wheat production and food security under the increasing threat of climate change.