Susceptibility Assessments of Tomato Genotypes to Root Knot Nematodes, Meloidogyne javanica

Root-knot nematodes, Meloidogyne spp., are one of the important plant parasitic nematodes of tomato in the world. The most suitable control method of plant parasitic nematodes is the use of resistance sources and tolerant cultivars. In the earlier studies, the results showed thatonly 2% (19 out of 537 varieties) were resistant and tolerant to the root knot nematodes. In the supplementary studies, the susceptibility of these 19 tomato cultivars were reassessed again, against M. javanica, in the two completely randomized design experiments in the greenhouse and field conditions for the two continuous years. The tomato plants were evaluated 70 days after inoculation on the basis of the gall indexes (GI), final populations (Pf), reproduction factors (Rf) and the root and or the stem weights. The results showed that, the cultivars No.136 and 109 with GI=2, Rf=4.68 and GI=2.25, Rf=28.4 are tolerant cultivars to the nematode, M. javanica in the greenhouse respectively. Also, the cultivar No. 100 was considered to be a susceptible one, with GI=3.25 and Rf=0.97. Whereas, in the field conditions, the cultivars 136 and 109 proved to be tolerant with GI, 1.9 and 1.6 respectively.