Studies on the potential ripening mutants to extend shelf life in tomato (Lycopersicon esculentum Mill.)

Abstract

Studies on potential ripening mutants to extend shelf life in tomato were undertaken with a view to compare shelf life, lycopene, firmness, and other attributes of ripening mutants, with normal ripening cultivars including firm fruited ones and F1 hybrids using normal ripening lines in crosses with nor and alc. shelf life (50% fruits turned soft) of the alc lines IHR 1137 and 1313 was 30 and 37 days, respectively, compared to 37 days in nor at room temperature. Their corresponding values at 20 ºC temperature were 44.67 and 70 days. Shelf life differed between the normal ripening varieties scope for isolating better keepers within the available tomato lines, (2) nor and alc. shelf life was much superior. The better colour development in alc lines could make them more suitable as parents in a breeding programme for extending shelf life. Mean shelf life of F1 was significantly superior to their normal parents but lower than nor and alc genotypes under ambient and constant temperature (20 ºC). Highest mean Shelf life observed was 21.6 days and 51.0 days at ambient and constant temperature (20 ºC) respectively in Floradade x nor. The corresponding values were 20 and 30 days in Floradade x 1137, Floradade x nor had the most delayed initiation of softening (21 days) followed by Floradade x 1137 (16.5 days). There was correspondence of lycopene content innormal parents and lycopene in F1s. F1s with nor had low lycopene content at various stages of ripening compared to F1s with alc. The crosses of nor and alc with the high pigmented (hp) line IHR 1143 had significantly higher lycopene. There was an apparent correlation between firmness and shelf life, among normal ripening lines Floradade had maximum firmness value of 5.15 and 4.3 kg at B and D stages, respectively. IHR 709, IHR 674 and Se1-4 were next best for firmness. Significant differences were not observed between mutants normal ripening lines for yield, but highly significant differences were observed between parents and F1 hybrids