Mechanism of resistance of eggplant (Solanum melongena Linn.) to cotton leafhopper (Amrasca biguttula Ishida); 1: biological bases of resistance
1990
Lit, M.C. | Bernardo, E.N. (Philippines Univ., Los Banos, College, Laguna (Philippines). Inst. of Plant Breeding)
The eggplant varieties PI-381272-2 and PI-386257-11 which were resistant to the cotton leafhopper, Amrasca biguttula (Ishida), in the field were significantly less preferred for nymphal and adult feeding under greenhouse conditions than the moderately resistant PI-381160 or the susceptible Dumaguete Long Purple and Kurumi Onaga. Greater adult preference of Kurumi Onaga was further demonstrated by the greater number of probing punctures and amount of honeydew excreted. Kurumi Onaga was also highly preferred for oviposition as indicated by greater number of eggs laid or newly hatched nymphs counted. The lower adult leafhopper survival, percentage of nymphs becoming adults, growth index and number of eggs laid, as well as the longer developmental period, reduced body length of fifth instar nymphs and shorter adult life in the resistant varieties PI-381272-2 and PI-386257-11 all suggested antibiotic effects. Tolerance to leafhopper infestation of the resistant eggplant varieties studied was not demonstrated conclusively because the adult insects used reproduced during the observation period and insect feeding appeared minimal. Nymphs are recommended for use in future tolerance studies. As a whole, results showed that the important mechanisms of resistance in the eggplant varieties studied were antixenosis and antibiosis.
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