Population dynamics of mycorrhizal fungi in rhizosphere of pigeon pea [Cajanus cajan (L.) Millsp.]

Soil samples collected from the rhizosphere of Pigeon pea [Cajanus cajan (L.) Millsp.] to evaluate the population dynamics of vesicular arbuscular mycorrhizae (VAM). Root colonization by native VAM fungi was recorded minimum in early stages of plant growth which significantly increased with the age of plants and became highest at maturity. Maximum VAM colonization in different blocks of the district ranged between 71-86% during both the years. Spore population was recorded maximum in soil samples collected at early stage of plant growth which significantly decreased of VAM fungi belonging 4 genera (Glomus sclerocystis, Acaulospora endogen) were identified. Among these Glomus mosseae and Sclerocystis rubiformis were found most dominating and widely distributed in all the blocks followed by Acaulospora longula  and Sclerocystis clavispora  which were distributed only in 12 blocks of the district. Acaulospora spinosa and Glomus diaphanum were recorded only from two blocks and their prevalence were least. Colonization per cent have negative correlation with spore density at different crop growth stages.