Genetic diversity for cell membrane thermostability, yield and quality attributes in cotton ( Gossypium hirsutum L.)

An experiment was performed to detect the genetic diversity and heat tolerance in sixty cotton ( Gossypium hirsutum L.) genotypes at Cotton Research Station D. I. Khan during the crop Season 2016–2017 in randomized complete block design in which three replications were used. These genotypes were evaluated for various morphological [plant height (cm), monopodial branches plant −1 and sympodial branches plant −1 , bolls plant −1 , boll weight (g) and seed cotton yield (g plant −1 )], physiological [relative cell injury percentage (RCI%) and chlorophyll content] and fiber quality traits [ginning out turn (%), fiber strength (g tex −1 ), micronaire value (µg inch −1 ), fiber length (mm) and uniformity index (%)]. Genetic analysis revealed that genotypes were containing marked phenotypic variabilities. High values of GCV, PCV, heritability and genetic advance were found for monopodial branches plant −1 , boll weight, seed cotton yield plant −1 , RCI%, chlorophyll contents and micronaire value. Variable trends of RCI% among the genotypes showed different levels of cell membrane thermostability. The results of RCI% indicated that Neelam-131 (32.34%), Sitara-008 (36.26%), Sitara-009 (39.89%) and Thakkar-80 (40.22%) had lower RCI% which depicted their higher cell membrane thermostability. These four genotypes were also superior in seed cotton yield having 124.12 g, 112.78 g, 102.63 g and 98.25 g plant −1 respectively. Three principle components were depicted having Eigen value > 1 and cumulative variation of 70.4% in which the contribution of individual PCs was; PC1 (48.3%), PC2 (11.3%) and PC3 (10.9%). Score plot revealed that Auriga-216, VH-Gulzar, Thakkar-80, Neelam-131, Sitara-008, BH-184, CRIS-600IR-NIBGE-7, VH-327 and FH-Noor were the most divergent genotypes and hence can be effectively utilized in the future breeding program.