To understand the impact of heat stress on agro-morphological and fiber quality-related traits in cotton, nine locally developed cotton genotypes were grown under heat stress conditions (Late sowing) at the cotton research station, Bahawalpur. Genotypes were laid-out under randomized complete block design (RCBD) in triplicates, where plant to plant and bed to bed distance was maintained as 30 cm and 75 cm, respectively. Data was collected from selected, guarded plants for agronomic as well as fiber quality-related traits. The resultsunveiled the presence of significant variations for studied traits under high temperature conditions. The correlation analysis revealed the significant association of seed cotton yield with plant population (0.403**), monopodial branches per plant (0.267**), fiber strength (0.070*), CLCuV incidence percentage (-0.475**), fiber length (-0.447**), nodes per plant (-0.186*), sympodial branches per plant (-0.186*), and fiber fineness (-0.077*). The multivariate approaches i.e., Principal component, biplot, and cluster analysis classify and characterize cotton genotypes on the basis of their heat tolerance capacity. Moreover, these multivariate analyses showed that BH-377, BH-272, and BH-283 were the most heat tolerant genotypes while BH-283 and BH-284 showed comparatively good CLCuV tolerance. Therefore, these genotypes should be recommended for sowing in heat and CLCuV effected areas of Pakistan after their large-scale, multilocation testing.

The genetic variability and correlation parameter studies for seedling traits viz; fresh root length, fresh shoot length, fresh shoot weight, dry shoot weight, tissue moisture percentage and root/shoot ratio in 40 accessions of cotton germplasm, including both local and exotic available at different research stations and institutes of Pakistan were carried out under greenhouse in the department of Plant Breeding and Genetics, University of Agriculture, Faisalabad, during the year 2006. Sufficient genetic variability was observed for seedling characters like root length, shoot length, shoot fresh weight, shoot dry weight, tissue moisture percentage and root/shoot ratio under normal and water stress conditions. Based on rooting character and root/shoot ratio, three drought-tolerant cotton genotypes 149-F, BH-124 and DPL-26 and three drought susceptible VH-28, FH-945 and CIM-446 were selected. Correlation coefficients under normal conditions were greater than under drought stress, and the direction of correlations of seedling traits in most cases remained the same. Under normal (r = 0.72) and drought (r = 0.48) conditions, shoot length and root length, were positively correlated, indicating a corresponding increase in shoot length with an increase in root length and vice versa.