Interspecific hybridisation of Lathyrus sativus (Guaya) with wild Lathyrus species and embryo rescue

Abstract

Lathyrus sativus is an economically important legume crop cultivated for food and forage in Asia and Africa. The use of this hardy drought tolerant and high yielding crop, however, has been limited because of a neurotoxin, _-N-oxalyl-L-_,_-diaminopropionic acid (ODAP) in the seeds. The objective of this study was to increase the genetic diversity of L. sativus by interspecific hybridisation with wild Lathyrus species devoid or with very low ODAP content. This would in turn assist to study the biochemical and genetic mechanisms which control the biosynthesis of ODAP. L. sativus was crossed with 12 wild Lathyrus species. Except for the reciprocal crosses of L. sativus and L. pseudo-cicera, others failed to develop viable seeds. In several of the interspecific hybrids, pod development was observed but embryos aborted during early stages of development. Embryo culture was attempted to rescue these immature embryos. The response of the interspecific hybrid embryos to in vitro culture varied. Cell proliferation and callus induction were observed in most of the combinations, and mature plants were regenerated from immature embryos of a cross between L. sativus (male parent) and L. cicera (female parent) both of which contain ODAP. However, it is expected that, with few modifications, this method will be useful in other interspecific hybrid combinations of Lathyrus.



Key Words: Hybridisation, Lathyrus, lathyrine, Neurotoxin, ODAP


(African Crop Science Journal: 2000, 8(2): 129-136)