Influence of greengram based cropping sequences on the population of Meloidogyne spp. and performance of the subsequent greengram crop

The experiment was conducted for two years to find out crops in a rotation which were effective and economical to manage root-knot nematode for green gram based cropping system in root-knot nematode infested field. Green gram, chickpea, wheat, cowpea, cluster bean, cabbage and cauliflower were included in rotation. Green gram and chickpea were susceptible to root-knot nematode therefore; nematode population and root-knot index were maximum in green gram-chickpea-green gram rotation. Green gram-wheat-fallow rotation was found most effective in which nematode population and root-knot index were minimum but this rotation was not found economical. In rotation of green gram-cabbage-cowpea (resistant to root-knot nematode), rootknot nematode population and root-knot index were increased when green gram was taken in kharif but both were decreased in rabi when cabbage (poor host) was taken and they were further decreased when root-knot nematode resistant cowpea was taken. This crop rotation was found effective to manage root-knot nematode with higher income as compared to rest of the rotations. Maximum reduction in root-knot index and final nematode population and increase in yield was recorded in green gram-wheat-fallow rotation. Green gram-cabbage-cluster bean gave maximum income per year and it was 328.21 per cent higher than rootknot nematode susceptible crop rotation i.e. green gram-chickpea-green gram.