EVALUATION OF FORTY MAIZE GENOTYPES FOR RESISTANCE TO MAIZE STALK (Sesamia calamistis Hampson) BORER
Keywords:
Genotype, Infestation, larvae, Maize, Severity, Stalk borerAbstract
Maize is the most cultivated cereal in the world followed by rice and wheat for its high nutritional value because of its carbohydrate content. However, sustainable maize production especially in the developing world is threatened majorly by stem boring species such as moths belonging to the families Noctuidae and Pyralidae. Therefore, the trial aimed at evaluating the performance of some selected maize genotypes under stem borer infestation. A screenhouse experiment consisted of 40 treatments (maize genotypes designated as M-G1 to M-G40), arranged in a Completely Randomised Design with three replicates. The maize genotypes were obtained from the Breeding Unit of the International Institute of Tropical Agriculture (IITA) Ibadan, Nigeria. Three trials were conducted; each trial comprised forty pots replicated three times, making a total of one hundred and twenty pots, filled with 15kg of steam-sterilized soil. Infestation of maize with stalk borers (Sesamia calamistis) was done by introducing nd four, 2 instar larvae to each stand of maize at 4 weeks after sowing (WAS). Data were collected on the number of plants that suffered stem-lodging and dead heart. Also evaluated were plant height at 4, 6, 8, 10 and12 WAS, number of days to 50% tasseling, number of days to 50% silking, ear height, ear position, number of ear per plant, grain moisture, stem diameter, plant stand at harvest and grain weight. Results indicated that the maize genotypes M-G8, M-G9, M-G17, M-G20, M-G25 and M-G27 had lower severity of infestation. On the other hand, M-G39, M-G15, M-G27, M-G30, M-G32, M[1]G12, M-G16, M-G2, M-G37, M-G19, M-G18, M-G24, M-G28, M-G6, M-G13, M-G23, M-G7, M-G5, M-G34, M-G8, M-G9, M-G28, M-G17, M-G10, M-G22, M-G31 and M[1]G38 were tolerant to dead heart, while M-G1 M-G2, M-G6, M-G13, M-G14, M-G18, M-G19, M-G24, M-G29, and M-G33 were tolerant to rotten ear. In yield performance, M-G27 had the highest (24.33 g/plant) significant (P
<0.05) grain weight. Therefore, selection of maize genotypes such as M-G31, M-G23, M-G8, M-G17, M-G28, M-G9, MG16, M-G5, M-G28, M-G34, M-G37, M-G27, M-G19, M-G10, M-G23, M-G38, M-G13, M- G4, M-G34 and M-G6 should be considered forpossible maize stalk borers- tolerant genes evaluation.>