Early-flowering mutants of Medicago ploymorpha var. Polymorpha

Abstract

Treatment of dry seeds of Medicago polymorpha L. var. polynzovpha with 20 krad gamma rays resulted in a large increase in variation for flowering time. Selection among spaced plants in the M2 and M3 generations, primarily for early flowering and secondarily for plant vigour and fertility, resulted in the isolation of mutant lines which flowered from 2 to 3 weeks earlier than the unirradiated controls and which were comparable in vigour with the unirradiated controls. This method of generating variability for plant improvement programmes proved to be simple, relatively quick, and economical (c. 1000 plants x 4 generations). It is recommended for more extensive use with self-fertilizing annual species where the primary selection criteria are clear cut and simply measured.