Reaction of snap bean (Phaseolus vulgaris L.) Cultivars to nematode (Meloidogyne incognita )

Abstract

Snap beans are an economically important commodity grain legume produced in Ethiopia for food security and to incur foreign currency. However, the production of this crop particularly in the rift valley of Ethiopia is impaired by plant parasitic nematodes. The current study aimed at evaluating the reaction of snap bean cultivars those are in the pipe line BC4.4 and Plati, and cultivars those have been in production Dwarf bean Sony, Dwarf bean Faraday, Serengeti and Amy were included in the study. Pot experiment was carried out under greenhouse condition in complete randomized design (CRD) with five replications and one level of nematode population density. Each plant was inoculated with 1000 second stage juveniles (J2) previously maintained on tomato plants while uninfected plants served as a control. Eight weeks after infection, pod number, pod weight, root fresh weight, shoot fresh weight, number of nematodes per 100gram of soil, number of nematodes per plant and the multiplication rate of the nematode were taken. All the tested cultivars reacted differently and their yield and yield components also significantly (P<0.05) different between the cultivars. High root fresh weight (10.7g) recorded from the control of Dwarf Sony and shoot fresh weight (26.5g) performed by infected Dwarf Sony and both lower pod number (3) and pod weight (3.14g) recorded for cultivar BC4.4. The multiplication rate of nematode population for all evaluated cultivars in Pf/Pi > 1 found to be susceptible for Meloidogyne incognita. Even though the values of the reproduction factor were numerically different, all the cultivars grouped under excellent host range. Highest yield gained by Amy and Dwarf bean Faraday under high nematode reproduction while the least yield gained by cultivar BC4.4. So, using different initial population density and other additional available cultivars would help to determining threshold level of the nematode and it will be the future line of work.