GENOTYPE-SPECIFIC NORMALIZATION OF SOYBEAN SOMATIC EMBRYOGENESIS THROUGH THE USE OF AN ETHYLENE INHIBITOR

The effect of ethylene on somatic embryogenesis from cotyledons of soy bean (Glycine max) cultivars 'Bragg', 'IAS-5', and 'RS-7' was studied through the application of silver nitrate or aminoethoxyvinylglycine. The addition of these chemicals to the induction medium had no effect an embryo induction, in spite of aminoethoxyvinylglycine having decrea sed ethylene production and silver nitrate enhancing it. However, subs equent histodifferentiation and conversion capacity of somatic embryos was affected by treatments applied to the induction medium. The effec ts of ethylene on embryo histodifferentiation and conversion were geno type-specific. Cultivars 'IAS-5' and 'RS-7' produced high frequencies of dicotyledonous embryos and had high conversion rates. These were al so the least affected by alterations in ethylene production. For 'Brag g', which has a low regeneration capacity, the use of aminoethoxyvinyl glycine led to a significant improvement in the frequency of normal em bryo formation as well as in the frequency of conversion into plants. The results suggest that the use of ethylene inhibitors during the ind uction process may facilitate plant recovery from soybean genotypes, s uch as 'Bragg', which have a low regeneration capacity.