Physiological traits coupled with water deficit tolerance by using multivariate analysis in cotton genotypes.

Abstract

The water shortage is a serious hazard for food security in the world. It is the alarming situation for the plant breeders to recognize and build up drought tolerant field crops germplasm. The water deficit tolerance magnitude rely on various soil and plant associated factors such as capacity of soil to accumulate moisture, rainfall distribution, rate of evapo-transpiration and root uniqueness. The present study was done at Central Cotton Research Institute, Multan to screen cotton germplasm against water deficit by irrigating the plants at three moisture levels at seedling stage i.e., 40, 70, and 100% of the pot capacity. The data on root length, fresh root weight, shoot length, fresh shoot weight, dry root weight, dry shoot weight and ratio of root and shoot were collected of 45 days plants after exposing to water deficit. Mean values of seedling parameters revealed differences for water deficit tolerance. Cluster analysis was performed by using Ward's method (1963). Five clusters (I, II, III, IV and V) comprised of various genotypes of cotton were observed at three moisture levels. Cluster I showed the genotypes having almost maximum values of root shoot parameters while cluster V with minimum values at all the moisture levels. These results showed the presence of drought tolerance genotypes in cluster I and susceptible genotypes in cluster V. In Biplot analysis, variables and genotypes are super imposed on the plot as vectors. The genetic variation in genotypes in different cluster showed the existence of water deficit tolerance which could be applied for the evolution of drought tolerant genotypes.