When a plant is subjected to heat stress, a number of genes are turned on, resulting in increased level of metabolites and proteins, some of which are responsible for conferring a certain degree of protection against stress. Heat shock proteins are found to be the major molecular determinants, which play a crucial role in plants against heat stress. For the determination of molecular determinants, there is a need of contrasting genotype, and to get a contrasting genotype a proper screening of germplasm is necessary. Screening can be done different basis of biochemical,genotypic and phenotypic parameters. In this book some of these parameters are studied.