Pattern of nodulation and biological nitrogen fixation in grasspea (Lathyrus sativus L.) genotypes

Abstract

As in other grain legumes, grass pea (Lathyrus sativus L.) fixes atmospheric N2 at root nodules in association with rhizobium and thereby enriches soil fertility. In this context the study on nodulation and biological nitrogen fixation in grass pea assumes a practical significance. Two genotypes of grasspea namely Nirmal evolved in West Bengal and P-24 at IARI, New Delhi were grown without any fertilizer at the farm of Bidhan Chandra Krishi Viswavidyalaya, Kalyani, which represents alluvial soild having pH 6.3 and NPK of 0.09%, 0.4% and 0.29% respectively. Samples of four plants were collected without causing any damange to the roots at 30 days, 55 days (flowering started) and at 80 days after sowing when pods were fully developed. Nodule counts were done from primary and lateral roots of 5 cm of root length as also beyond 5 cm. From these two root zones nodules were analysed for their nitrogenase activity through acetylene reduction method as suggested by Hardy et al. [1].