In vitro New Approaches for Shortening of Generation Cycles and Faster Breeding of Grass pea (Lathyrus sativus L.)

Abstract

Flowering is a complex process regulated by a combination of genetic and environmental factors. Grass pea (Lathyrus sativus L.) grows as long day plant under natural conditions with single breeding cycle per annum. There is need to develop strategies by accelerating breeding activities making it possible to grow more than one generation per annum that is impossible under natural conditions. In line with this objective, this mopho physiological study searched for alternatives by treating explants in vitro with 6-benzylaminopurine (BAP) and α-naphthaleneacetic acid (NAA) to induce earlier flowering with aim of leading to accelerated breeding. Nodal junctions bearing about 0.5 cm portion of internodes on both sides were used as explants. The Murashige and Skoog (MS) medium supplemented with 2 mg L-1 BAP and 1 mg L-1 NAA was found optimum for production of multiple shoots. The regenerated plantlets induced floral buds and flowers within two weeks of culture on MS medium supplemented with 0.1 - 0.5 mg L-1 BAP. Flowering was observed on the regenerated plantlets with an average number of 4.30± 0.32 flowers per plantlet that continued during acclimatization. In vitro rooting was observed (83.43±2.92%) in the presence of MS medium containing 0.10 mg L-1 indole butyric acid (IBA). The regenerated plants were acclimatized in the greenhouse, where they set seeds. It was concluded that it was possible to obtain 4.3 generations per annum. The results are very encouraging and could save time significantly for accelerated breeding of grass pea.