In vitro culture of pods from annual and perennial Medicago species.

Because most interspecific Medicago embryos abort before they can be excised and cultured, our objective was to grow young pods in vitro. Various media were used to grow three-day-old pods of annuals [diploids, M. blancheana Boiss., M. disciformis DC., tetraploid M. scutellata (L.) Mill.] and perennials (diploid M. falcata L., tetraploid M. sativa L.).Few pods of perennial species grew to maturity on media containing modified Hoagland's plus 1% glucose or sucrose with or without 5% potato extract. Increasing sucrose to 6% increased the percentage of M. sativa pods that produced mature seeds. On DM (differentiation medium), the best medium, the percentage of pods producing viable seeds was: M. blancheana (82), M. disciformis (81), M. scutellata (48), M. sativa (63), M. falcata (15). DM plus 1 ppm indoleacetic or gibberellic acid did not enhance seed production.