Studies on biology molecular characterization and eco friendly management of root knot nematode meloidogyne graminicola of basmati rice

Abstract

newline Root knot nematode (Meloidogynegraminicola) has been reported a serious pest of paddy, especially in light textured soil and irrigated upland condition. It causes damage to nurseries and main field. The main characteristic symptoms produced by M. graminicolaare terminal hook shaped or spiral galls on the rootsand other symptoms of damage include patches of stunted and yellowish plants in field. Fifty three promising rice varieties were screened against rice root knot nematode out of which 33 were basmati and 20 were non-basmati under pot condition to know the response of the varieties against root knot nematode. Out of 53 varieties in which 18 variety showed moderately susceptible reactionviz.,UnnatPusa Basmati, CSR 30, Malviya Basmati, Kasturi Basmati, Silky, PR-13, TilakChandan, Satthi, Ganga Kaveri 7029, Sarju 52, Ganga Masuri, DhanRekha, BRRI 26, PR-21, HRK-47, PR-14, BenamBadshaand B-40 and rest 35 variety were shown susceptible reaction against rice root-knot nematode. No any variety was shown resistant and highly susceptible reaction against root knot nematode.Pathogenicity tests confirmed the nematode impact on basmati rice crop causing galls formation on roots in relation to inoculum levels. The life cycle of rice root knot nematode was completed in 25-31 days after inoculation in which, duration of second, third, fourth, adult and eggs stages lasted for 3-7, 8-12, 13-16, 25-28 and 30-31 days respectively. Molecular characterization of the nematode, using ITS, D2-D3 28s rRNA,cox II-16S rRNA and Mg-F3/Mg-R2 primers, identified the presence of M.graminicola in rice fields with high nucleotide homology. For management of rice root knot nematode, use of chemicals is becoming more expensive and undesirable due to environmental hazards. Use of bio control agents coupled with organic amendments is an eco-friendly, sustainable and economically feasible method for nematode management. In-vitrostudy of culture filtrate of selected bio-agents was tested on larval mortality and egg hatching of M. gramin