Asymmetric somatic hybridisation between the annual legumes Medicago truncatula and Medicago scutellata

Interspecific asymmetric somatic hybrids have been produced between the sex ually incompatible annual Medicago species Medicago truncatula and M. scute llata using only one regenerable parent and improved protoplast techniques. Regenerable M. truncatula leaf protoplasts were inactivated by lethal dose s of iodoacetamide. Cotyledon protoplasts of non-regenerable M. scutellata were produced from 9 to 13 day old gamma-irradiated cotyledons. Polyethylen e glycol was used for protoplast fusion, and its successful use depended on a strategy to eliminate toxic effects. More than 50 mature regenerated pla nts were obtained from the fusion products and amplified fragment length po lymorphism and chromosome analysis of a sample of 20 plants allowed the ide ntification of two asymmetric hybrid plants. This technique is suitable for transferring characters from incompatible annual Medicago species to Medic ago truncatula.