EVALUATION OF COTTON GENOTYPES FOR DROUGHT TOLERANCE AND THEIR CORRELATION STUDY AT SEEDLING STAGE

Drought stress is considered as the most limiting factor that reduces crop productivity all over the world. Among the abiotic stresses, drought adversely affects the plant growth and development, consequently the yield. The current research experiment was conducted in RCBD factorial arrangement with two irrigation treatments (non-stress and water stress at seedling stage) in four replications at experimental field, Department of Plant Breeding and Genetics, Sindh Agriculture University, Tandojam during 2010. Twelve most popular upland cotton cultivars viz. CRIS-134, CRIS-342, Sadori, Chandi, Sindh-1, NIAB-78, CIM-496,CIM-499, CIM-506, CIM-534, BH-160 and Bt cotton (Australian origin) with diverse characters and origin were selected for the study at seedling stage for physiological as well growth parameters under water stress conditions. The growth and physiological traits were comprised of shoot length (cm), root length (cm), number of lateral roots ( NLR) , leaf area (cm2) (LA) , leaf relative water content (RWC), excised leaf water loss (ELWL%) , stomatal density(ST) and stomatal conductance (SO was calculated. The significance of treatments x genotypes interactions revealed that cotton cullivars performed variably over irrigation regimes. Water stress significantly affected shoot length, root length, number of lateral roots, leaf area, relative water content, excised leaf water loss, stomatal conductance, and stomatal density. Further correlation coefficient revealed that traits were positively and significantly associated except that stomatal conductance was negatively associated with shoot length, root length, and no of lateral roots.