Diallel analysis of production traits among domestic, exotic and mutant germplasms of Lycopersicon

ABSTRACT

The effects of wild germplasm on tomato fruit shelf life have not yet been completely evaluated. Three different genotypes of Lycopersicon esculentum (a cultivated variety, a homozygote for nor and a homozygote for rin), LA1385 of L. esculentum var. cerasiforme, LA722 of L. pimpinellifolium, and 10 diallel hybrids were assayed. Mean values of fruit shelf life, weight, shape, and mean number of flowers per cluster were analyzed after Griffing (1956, Aust. J. Biology 9 463-493), method 2, model 1. Both general and specific combining abilities (GCA and SCA) were significant for the four traits. Negative unidirectional dominance was detected for fruit weight and shelf life, while bidirectional dominance was detected for fruit shape and mean number of flowers per cluster. SCA was greater than GCA for shelf life, so nonadditive effects predominantly accounted for this trait. In the heterozygous state, rin had smaller mean effects than nor. Wild accessions were able to prolong shelf life per se, and in crosses to the cultivated variety. The cross between the homozygote for nor and LA722 yielded the longest shelf life among hybrids