Genetic analysis and RAPD markers for drought tolerance in tomato genotypes

Genetic parameters, heritabilities and genetic variability were assessed in five tomato genotypes and their F 1 crosses using phenotypic data and RAPD markers under normal and drought stress conditions. The results showed that mean squares of the genotype by environment (GxE) interaction were found to be highly significant for all studied traits, suggesting a differential response of studied genotypes to drought stress. The magnitudes of ơ 2A were higher in magnitude than those of ơ 2D for most cases indicating that the additive gene action played a major role in the inheritance of these traits. Moreover, the interaction of ơ 2A xE was less than ơ 2D xE for most studied traits, suggesting that the additive gene effect was more stable over the environments than non-additive effect. These results were verified by the estimates of the broad- and narrow-sense heritability obtained for different traits. The RAPDs analysis showed that 31 out of 57 bands were polymorphic. The percentage of polymorphism ranged from 20 (OPP-05) to 100% (OPA-03). The UPGMA cluster analysis based on RAPD markers separated the genotypes into two different clusters, while the dendrogram based on phenotypic data divided into two clusters. The Polymorphism information content (PIC) values varied from 0.10 (OPB-01) to 0.46 (OPA-03).