ABSTRACT In the present study, the damaging effects of six inoculum densities of Meloidogyne incognita were compared on a resistant (Long Green) and a highly susceptible (Mirage) cultivar of cucumber. All the inoculum densities of M. incognita resulted in significant reductions in growth and yield variables of both the cultivars over their controls. The reductions in resistant cultivar were significantly lower as compared to the highly susceptible cultivar at all inoculum levels. The highest inoculum level caused the maximum reductions in growth and yield variables while the lowest inoculum level resulted in the minimum reductions. The reductions in growth and yield variables increased with an increase in the inoculum density showing a positive relationship. On the other hand, the inoculum levels caused an increase in root weight. The higher inoculum levels caused higher increases while at lower inoculum levels, the increases were lower. The increases in root weights were significantly lower in the resistant cultivar when compared to the highly susceptible one showing a direct relationship between the increase in root weight and inoculum levels. Similarly, significant differences in number of galls and egg masses were noticed between the resistant and highly susceptible cultivar at all inoculum levels. The galls produced on highly susceptible cultivar were significantly higher as compared to the resistant one. A direct relationship was observed between inoculum levels and number of galls and egg masses. On the other hand, all the inoculum levels varied significantly regarding reproductive factor on the resistant and highly susceptible cultivars.

ABSTRACT Meloidogyne incognita is one of the most widespread and damaging plant-parasitic nematodes throughout the world and substantially affects growth and yield of okra (Abelmoschus esculentus L). In the present study, effects of M. incognita on yield parameters of 12 okra cultivars with varying levels of resistance or susceptibility were assessed. M. incognita caused significant reductions in yield parameters of okra plants of all the cultivars. Maximum reduction of 34.1% in yield was observed in highly susceptible (HS) cultivar Sharmeeli. The nematode caused 20 and 17.6% reductions in yields in susceptible (S) cultivars Okra Sindha and Anmol, respectively. Moderately susceptible (MS) cultivars suffered 5.9 to 12.9% reductions in yields. In case of moderately resistant (MR) cultivars (Sanam, Dikshah, Arka Anamika, Ikra-1 and Ikra-2), the reductions in yields were the minimum and ranged from 2.9 to 6.5%. The reductions in other yield parameters of okra cultivars were observed in the order HS > S > MS > MR. As the MR cultivars suffered less damage by the nematode, they are recommended for cultivation in fields heavily infested with M. incognita.