In vitro regeneration of grass pea (Lathyrus sativus L.) From cotyledonary node explants

Abstract

Grass pea (Lathyrus sativus) have many valuable characteristics and its cultivation requires the least crop management but, its full potential has not been utilized because of the presence of the neurotoxic amino acid β-N-oxalyl-L-αβ -diaminopropionic acid (ODAP) which causes neurolathyrism in human beings on prolonged consumption. Conventional breeding practices and other approaches explored to date have not been successful in considerably reducing the toxin. Therefore, integration of in vitro techniques such as somatic hybridization, somaclonal variation and genetic transformation can contribute significantly to meet the challenge. Hence, the present study was carried out to evaluate the in vitro regeneration capacity of some grass pea genotypes and eventually to optimize protocol for in vitro propagation of the crop as in vitro regeneration capacity is prerequisite to alleviate the ODAP problem through in vitro techniques. In this study, three experiments were conducted: cotyledonary node shoot initiation of four genotypes (IVATLS-LS -B2, IVATLS-LS –B1, IVAT-LS- 690, and IVATLS-655),on MS media withthree concentrations of BAP (1, 2 and 3mg/l) + 0.1mg/lNAA were tested whereas for in vitroshoot multiplication, the combination effects of four levels of BAP (1, 2, 3, and 4 mg/l) and Kn(0,1,2 and 3mg/l) were used for the selected genotype (IVAT-LS-690 and for in vitro rooting, IBA and IAA alone with four concentrations each (0.1, 0.25, 0.5 and 1.0mg/l) were evaluated on half strength MS medium. Among the four genotypes tested for shoot initiation, shoot nitiation percentage was the highest (100%) for IVAT-LS-690,on MS medium augmented with 2 mg/l BAP +0.1mg/lNAA. With regards to the in vitro shoot multiplication of IVAT-LS-690, 3mg/l BAP+1mg/l Kn gave maximum shoot number per explant (11.5), and longest shoot (5.03cm). For in vitro rooting of this genotype, best result for percent of rooted shoot (86.66%), high number of roots per shoot (6) and longest root (4.9cm) were obtained from half MS medium supplemented with 0.5mg/l IBA and these rooted plantlets were acclimatized and established in soil. From this study it could be inferred that both genotype and BAP levels play crucial role for shoot regeneration capacity and the optimum hormonal combination for grass pea is genotype specific. MS media supplemented with BAP and Kn(3mg/l BAP+1mg/l) for shoot multiplication and half -MS medium supplemented with 0.5g/l IBA for rooting could be used for in vitro propagation of IVAT-LS-690 genotype. Therefore, this work could be used as a baseline for further studies on in vitro technique of grass pea aiming at meeting the challenge of ODAP