SOMATIC HYBRID PLANTS BETWEEN THE FORAGE LEGUMES MEDICAGO-SATIVA L AND MEDICAGO-ARBOREA L

Interspecific somatic hybrid plants were obtained by symmetrical elect rofusion of mesophyll protoplasts of Medicago sativa with callus proto plasts of Medicago arborea. Somatic hybrid calli were picked manually from semi-solid culture medium after they were identified by their dua l color in fluorescent light. Twelve putative hybrid calli were select ed and one of them regenerated plants. The morphogenesis of the somati c hybrid calli was induced by the synthetic growth regulator 1,2 benzi soxazole-3-acetic acid. Somatic hybrid plants showed intensive genome rearrangements, as evidenced by isozyme and RFLP analysis. The morphol ogy of somatic hybrid plants was in general intermediate between the p arents. The production of hybrids by protoplast fusion between sexuall y incompatible Medicago species is related to the in vitro responsiven ess of the parental protoplasts. The possibility of using somatic hybr id plants in alfalfa breeding is discussed.