Vol. 9, Special Issue 2, Part I (2025)

An experiment was conducted in the net house of Department of Nematology, A. A. U. Jorhat, during the rabi season of 2020 to study the pathogenicity of root-knot nematode, Meloidogyne incognita on bitter gourd (Momordica charantia L.). Bitter gourd germplasm ‘Priya’ was selected for this investigation mainly because of its high susceptibility to M. incognita. The pot experiment was carried out in a completely randomized design with five replications. Seeds were sown in 1kg capacity pots filled with sterilized soil and 10 days old seedlings were inoculated with second stage juveniles of M. incognita in a logarithmic series of check, associated check, 10, 100, 1000, 10,000 juveniles (J₂) per pot. After 45 days of inoculation, it was observed that at highest inoculum level plants had stunted growth, chlorotic leaves with very less number of branches. It was also observed that at the highest inoculum level the root system were very much reduced with larger galls and the galls coalesced within the roots. The treatments with no nematode i.e., check and associated check was found to be free from galls and egg masses. The plant growth parameters like plant height, shoot and root weight (fresh and dry) exhibited a declining trend from initial inoculum level of 100 J₂ to highest inoculum level of 10,000 J₂ per pot but the nematode multiplication factors viz., number of galls per root, number of egg masses per root and final nematode population in soil exhibited an increasing trend from initial inoculum level of 10 J₂ to 1000 J₂ per pot, but it declined at inoculum level of 10,000 J₂ per pot. In treatments with no nematode (check and associated check), no significant difference was found in plant growth parameters viz., plant height, shoot and root weight (fresh and dry) and nematode multiplication factors like number of galls per root, number of egg masses per root and final nematode population in soil. Further, no significant difference was observed in treatments between 10 and 10,000 J₂ per pot for number of galls per root, number of egg masses per root and final nematode population in soil.