GENOTYPE X SUCROSE INTERACTIONS FOR SOMATIC EMBRYOGENESIS IN SOYBEAN

Somatic embryogenesis is a route of plant regeneration in soybean [Glycine max (L.) Merr.]. This study was undertaken to test the ability of immature soybean embryos to produce somatic embryos across several sucrose concentrations. Cotyledons isolated from immature embryos of 16 soybean (G. max and G. gracilis Skvortz.) cultivars were cultured on embryogenesis media containing sucrose at concentrations of 5, 10, 20, and 30 g L-1. After 28 d in culture, the number of somatic embryos per pair of cotyledons was counted. The analysis of variance showed that the effects of genotype, sucrose concentration, and genotype x sucrose interaction were all highly significant. The genotype x sucrose interaction was analyzed further by regression of each cultivar on the mean of all varieties for each sucrose concentration. Highly significant heterogeneity of regression among the cultivars was recognized. Stability, as expressed by regression, and average response of cultivars to the various sucrose concentrations appeared to be under separate genetic control.