Characterizing tomato genotypes for high temperature stress adaptation in field conditions

The impact of heat stress on agriculture is severe and negatively impacts crop productivity. In tropical and subtropical tomato-growing regions around the world, poor fruiting of tomato plants caused by heat stress is a major factor in low output. The purpose of this study was to evaluate the responses of 58 tomato genotypes to high temperatures using a field varietal screening method. This work consists of using the collection of tomato genotypes to identify the genotypes that performed best under elevated temperatures of the summer season. The findings can be used for the development of superior tomato genotypes that are better suited to high-temperature environments. Exceeding optimum temperatures shortened the duration to first flowering, fruiting and maturation. Temperatures above the reference temperature caused irregular flower development, reduced pollen production, pollen viability, fruit drop, ovule abortion, and ultimately reduced yield, generating an excess of reactive oxygen species (ROS), oxidative stress, and metabolic mechanism instability. High temperatures severely caused flower shedding, with tomato plants losing 80% of their flowers and reducing fruit set. For the characteristics pollen viability, photosynthetic rate, membrane stability and fruit number, high values of genotypic coefficient of variability, phenotypic coefficient of variability, heritability, and genetic progress were discovered. All nine separate traits demonstrated additive gene action in trait expression and should be given the utmost weight in phenotypic selection. Eigen value > 1 and cumulative variance of 75.04% were shown for the four main components.