Parasitic nematodes and vesicular-arbuscular mycorrhizal (VAM) fungi associated with berseem (Trifolium alexandrinum L.) in Bundelkhand region

Samples of berseem (Trifolium alexandrinum) roots and rhizosphere soil from 25 locations of 5 districts in the Bundelkhand region were collected during the survey. Out of 7 genera of plant parasitic nematodes identified, both stunt (Tylenchorhynchus vulgaris) and spiral nematode (Helicotylenchus dihystera) were the most common and occurred in every sample. However, the population of the former species was observed to be generally high and was also frequently associated with stunted or abnormal growth of the plants. Spores of endomycorrhizal fungi occurred in every sample and out of 3 species identified, Glomus mosseae was the most prevalent. High population of stunt nematode was found to be associated with abundant mycorrhizal counts which indicate that both the organisms do not affect the development of each other. Pathogenicity test revealed that 1000 nematodes of T. vulgaris caused significant reduction in plant growth of berseem. A positive interaction between VAM and stunt nematode was observed in which the former offset nematode damage and increased the plant growth and phosphorus content of berseem in green house experiment.