Response of Tomato Genotypes to Root-Knot Nematode (Meloidogyne incognita) infection under Laboratory and Protected Cultivation

The root-knot nematode, Meloidogyne incognita is the most severe problem in tomato crop grown under protected cultivation. Finding and use of resistance against M. incognita in plant breeding program could be most valuable to control nematode incidence. The host response of 113 tomato genotypes were studied at three temperatures, 28 ± 2°C, 30 ± 2°C and 32 ± 2°C in Pluronic gel. The results revealed that change in temperature had a significant effect on the gall formation and juvenile penetration. Further, in pot screening under polyhouse condition out of 99 genotypes, 16 genotypes were moderately resistant, 81 susceptible and 9 highly susceptible. The response of moderately resistant genotypes obtained from pots screening was evaluated under naturally infested polyhouse beds with M. incognita population density of 5–6 J2s/cc soil, resulting in resistance breakage with only 5 genotypes out of 12 moderately resistant with reduced nematode incidence. Data obtained from this study revealed that temperature and soil nematode population density had a significant effect on resistance of tomato genotypes. The moderately resistant genotypes could be used to develop resistant cultivars.