Studies on host preferences of two races of reniform nematode, Rotylenchulus reniformis from India* Rao G.M.V. Prasada, Ganguly Sudershan Division of Nematology, Indian Agricultural Research Institute, New Delhi-110 012. *Part of Ph.D. thesis submitted by the senior author to P.G. School, IARI, New Delhi. Abstract A set of 13 crops was used to know the host preferences of two populations representing different host races of reniform nematode, Rotylenchulus reniformis, one from Delhi (Race 1)and the other from Andhra Pradesh (Race 4), collected from the roots of grapevine. Two crops i.e. chilli cv. Pusa Jwala and sorghum cv. SC-1 were found nonhosts for both the races since there was no penetration on the roots. Both populations formed eggmasses, in varying number (19–68 eggs/root system), on the roots of seven crops viz. bottlegourd cv. Pusa Summer Prolific Long, cowpea cv. Pusa Komal, castor cv. GAU-CHI, cotton cv. H-777, okra cv. Pusa Sawani, brinjal cv. Pusa Purple Long and tomato cv. Pusa Ruby, which were common hosts for both the populations. The populations exhibited marked differences in their capability to reproduce on four crops (pea cv. AP-1, bajra cv. Pusa-23, mustard cv. Pusa Bold and maize cv. Luxmi), on which Delhi-population produced eggmasses while AP-population could not. Fecundity of two races also varied from crop to crop. The two host races were thus further differentiated on the basis of their host preferences, with Delhi-population being more virulent and aggressive than the AP-population. Top Key words Host races, reniform nematode, Rotylenchulus reniformis. Top |