Response of Common Beans Varieties to a Mixed Population of Root Knot Nematodes (Meloidogyne spp) in Central Highlands of Kenya

Abstract

Response of eight bean varieties to Meloidogyne javanica and M. arenaria was evaluated under greenhouse and field conditions. The bean varieties were GLP2 (Rosecoco), GLP24 (Canadian wonder/Gituru), GLPX92 (Mwitemania), GLP585 (Wairimu), GLP1004 (Mwezi moja), GLP1127 (New mwezi moja), and two climbing beans (Vuninkingi and Gisenyi). .In the greenhouse test, two weeks old seedlings established on sterilized sandy loam soil were inoculated with 4000 nematodes comprising of second stage juveniles (J2) and eggs obtained from beans in the Central highlands of Kenya and maintained on tomato cv money maker in the greenhouse. Each treatment was replicated six times in a Randomized Complete Block Design (RCBD). Five bean varieties namely GLP2 (Rose coco), GLPX92 (Mwitemania), GLP585 (Wairimu), GLP1127 (New mwezi moja) and Gisenyi that were moderately resistance or resistant as revealed in the greenhouse experiments were evaluated under field conditions. Treatments were replicated four times and arranged in a RCBD. Greenhouse test was terminated 60 days after inoculation while the field test was terminated 90 days after planting. Plant growth, nematode damage as measured by gall indices and egg mass indices and reproductive factor were assessed. Based on these parameters, the host responses to the nematodes were categorized as resistance, moderately resistant, susceptible and moderately susceptible. GLP 585 was categorized as resistance or a poor host while Vuninkingi was rated the most susceptible among the eight varieties. The moderately resistant varieties were (GLPX92, GLP2, GLP1127 and Gisenyi, while GLP24 and GLP1004 were moderately susceptible.