Analysis of Physio-biochemical Variables of Selected Tomato Genotypes at the Seedling Stage under Temperature Stress Conditions Using Principal Component Analysis

Tomato (Solanum lycopersicum L.) is a temperature-sensitive vegetable crop. The present study was designed to analysis the 22 tomato genotypes under temperature stress. Germplasm was allowed to grow up to 28 days under optimal growth conditions and temperature stress was induced by incubating at 37° C for seven days in a plant growth chamber. The physio-biochemical parameters such as Chlorophyll content (CHL), total carotenoids contents (TC), relative water content (RWC), electrolyte leakage (EL), total dissolved solids (TDS) and proline (Pro) were evaluated to analyze the temperature tolerance capability of germplasm using Principle Component Analysis (PCA). Temperature stress responses varied considerably among the studied genotypes. Among the studied physio-biochemical variables, the EL and RWC variables showed higher contribution to F1 axes of temperature-stress biplot and these variables plays crucial role to segregate the genotype as tolerant and sensitive. The CHL and TC variables contributed more to the F2 axes of the temperature-stress biplot. The factor score that contributed to F1 axes of the PCA biplot under temperature stress concluded that TG7, TG13, TG3 & TG1 genotypes are tolerant and TG14, TG17, TG2 & TG19 are as sensitive genotypes. The analysis of the present results provides a basis for the selection of temperature-tolerant and sensitive genotypes at early growth stages and can be utilized in breeding programs to develop hybrids that can withstand high temperatures in agricultural crops.