Phenotypic and Genetic Divergence among Tomato Genotypes: Insights for Parental Selection and Yield Improvement

Abstract

This study assessed morphological diversity and genetic divergence among 25 tomato (Solanum lycopersicum L.) genotypes using 17 DUS-based descriptors and Mahalanobis D² statistics. The Shannon–Weaver diversity index (H′) indicated significant phenotypic variation, particularly in fruit traits. Uniformity in vegetative traits such as growth habit and stem pubescence (H′ = 0.00) reflected strong selection for determinate types suitable for commercial cultivation. In contrast, fruit shape (H′ = 1.61), locule number (H′ = 1.03), and total soluble solids (H′ = 1.00) exhibited notable variability, with moderate diversity observed in flowering time and leaf green intensity. Cluster analysis grouped genotypes into five clusters, showing considerable inter- and intra-cluster divergence. The highest intra-cluster distance was in Cluster IV (3.167), while the maximum inter-cluster distance occurred between Clusters II and V (5.519), identifying potential parents for heterosis breeding. Cluster V exhibited superior mean values for fruit number, diameter, ascorbic acid, and yield. Cluster III was notable for fruit weight and lycopene content, suggesting utility in nutritional improvement. Cluster I had the shortest crop cycle, beneficial for early production. Overall, the study highlights substantial phenotypic variability and divergence, offering valuable insights for selecting diverse parental lines in tomato breeding programs aimed at improving yield and quality traits.