Diallel Analysis of In Vitro Culture Traits in the Genus Lycopersicon

Estimates of genetic variability for in vitro culture traits among the genus Lycopersicon and evaluation of the gene effects involved in callus production and shoot formation were achieved. Five parents including wild and cultivated tomato genotypes and their nonreciprocal 10 possible hybrid combinations were assayed. The callus percentage (C = number of cultures that only produced callus × 100/total number of cultures), the regeneration percentage (R = number of cultures that differentiated into shoots or primordia × 100/total number of cultures) and the productivity rate (PR = total number of shoots/total number of cultures) of each genotype were calculated 45 days after culture initiation. Diallel analysis revealed genetic variability for in vitro culture response. Wild genotypes contributed to a reduction in callus production and an increase in shoot formation while the cultivated genotypes either had an opposite effect or did not modify the expression of culture traits. Hybrids had the lowest callus production and highest shoot formation percentage. Additive gene effects were mainly involved in the expression of C and R, while both additive and nonadditive gene effects were involved in expression of PR.