Vegetative growth and reproductive traits enable selection of heat-tolerant tomato genotypes from interspecific crosses

Abstract

ABSTRACT This study aimed to develop and select tomato plants tolerant to heat, from F2 populations for industrial processing and fresh consumption, obtained from interspecific crosses between Solanum lycopersicum L. × Solanum habrochaites Knapp & Spooner var. hirsutum (PI 127826). Populations derived from Redenção × PI 127826 (UZIP) and Santa Clara × PI 127826 (UZFS) were evaluated at the seedling, vegetative, and reproductive stages under elevated day/night temperatures (36/28 °C and 40/30 °C). The number of leaves, plant height, and resistance to injuries were assessed, as well as pollen viability and stigma receptivity. In the initial seedling screening, several genotypes outperformed the commercial parents. In the second screening, the cultivars Redenção and Santa Clara confirmed high sensitivity to heat stress, while the wild accession PI 127826 maintained tolerance at all stages. Out of the industrial processing plants, UZIP-40, UZIP-174, and UZIP-245 showed the best performance, with growth and injury resistance comparable to PI 127826. For fresh consumption, UZFS-39, UZFS-85, and UZFS-176 exhibited similar tolerance to the wild parent. These genotypes also maintained high pollen viability and stigma receptivity under heat stress, surpassing the commercial parents. The results indicate that interspecific selection enabled the identification of F2 genotypes capable of maintaining vegetative growth and reproductive functions under thermal stress. These populations represent promising sources for breeding programs designed to improve heat tolerance in tomato, both for industrial processing and fresh consumption.