Biometrical Analysis of a Mutant that Increases Shelf-Life of Tomato Fruits

Abstract

The nature and the magnitude of the genetic effects of a mutation, denominated ´firme‘, involved in the shelf-life trait expression, were studied through the generation-means and the Griffing’s approach. Plants of tomato (Lycopersicon esculentum Mill.) cv. ‘Santa Clara’, ‘firme’ mutant and the accesses BGH-6913, BGH-6914 and BGH6915 were crossed in a diallel cross, excluding reciprocals, and the F2 and backcrossed populations were obtained for the first two parents. The results of the generation-means showed that the mutation increases shelf-life, the mean and the additive genetic effects being the main responsible for the character expression. The dominance deviation and epistasis, in turn, was of secondary importance. Similar results were obtained by the Griffing’s approach, where the mean squares of GCA effects were higher than those from SCA. The ‘firme’ mutant and BGH-6913 genotypes showed the largest magnitudes for GCA, being, therefore, of interest for intrapopulation breeding programs for genotypes with greater potential for postharvest storability. The best combinations for obtaining gains in segregating progenies from biparental crosses, are ‘firme’ mutant x BGH-6913, BGH-6914 x BGH-6915 and ‘Santa Clara’ x BGH-6915