Assessment of genetic variability and multivariate analysis for yield and quality improvement in an interspecific F₂ population of tomato (Solanum lycopersicum L.) under high-temperature stress

Abstract

Heat stress is one of the major abiotic constraints limiting the productivity of tomato, especially at the reproductive stage. An interspecific F2 population developed from the cross PKM 1 × Solanum pimpinellifolium L. was evaluated at the Vegetable Research Station, Palur, Tamil Nadu, India, to identify important traits associated with yield improvement under high temperature conditions. The population was evaluated for yield, physiological and quality traits through analyses of genetic variability, correlation, path coefficient and principal component analysis (PCA). Results indicated considerable genetic variability among the segregants; high heritability along with high genetic advance (GA) revealed the dominance of additive gene action, indicating the efficacy of direct phenotypic selection. The major determinants of fruit yield under heat stress were fruit weight (FW), fruit set percentage (FS), number of clusters per plant (NCP) and number of fruits per plant (NFP), as revealed by correlation and path coefficient analyses. Principal component analysis is an efficient method which revealed extensive genetic diversity and identified promising segregants with superior yield and heat tolerance. These results provide useful selection criteria and genetic resources for developing high-yielding, heat-tolerant tomato varieties adapted to future climate scenarios.