Combining ability and heterosis studies in tomato (Solanum lycopersicum L.) for quality traits and yield

Abstract

Thirty crosses were done in tomato using ten genotypes as lines and three genotypes as testers in line × tester mating design. All the crosses along with parents were evaluated for combining ability and heterosis for quality traits and yield. H-86 was the good general combiner for titrable acidity, ascorbic acid, lycopene and shelf life, Azad T-5 was the good general combiner for TSS. Best specific combiner for TSS and fruit yield was Fla 7171 × Sel-7. A perusal of GCA/SCA variances revealed that SCA variances were of higher magnitude than GCA variances for yield, ascorbic acid and titrable acidity. It shows the preponderance of non-additive gene action governing these traits. For the fruit shape index, TSS, lycopene and shelf life, the GCA variance was of higher magnitude than the SCA variance, indicating the predominant role of additive gene action. The ratio of σ2gca / σ2sca is less than unity for all characters except fruit shape index, titrable acidity and ascorbic acid which also indicated the preponderance of non additive genetic variance. Best heterotic combination, for fruit yield and TSS was Fla 7171 × Sel-7, for fruit shape index was H-24 × Azad T-5, for ascorbic acid was Kashi Amrit × Kashi Sharad, for lycopene was H-86 × Azad T-5 and for shelf life was Floradade × Azad T-5. High heritability (>60%) combined with high genetic advance (>20%) was observed for shelf life, fruit yield, lycopene, TSS which indicates that these traits can be improved by simple selection.