Valuation of Some Aromatic Rice (Oryza sativa L.) Genetic Materials to Achieve Tolerant Resources for Rice Stem Borers (Lepidoptera: Pyralidae)

For selection of aromatic rice (Oryza sativa L.) lines, fifteen (15) genotypes (Graminales: Poaceae), were evaluated for insect pests detection and agronomic characteristic through field test. The rice stem borer incidence was recorded according to deadhearts, whiteheads and grain yield parameters from the natural pest infestation. In general, the results on abundance and diversity of pest's species at different stages of crop growth revealed the yellow stem borer, Scirpophaga incertulas (Walker), (Lepidoptera: Pyralidae), as most dominant insect pest. On the basis of percent damage, none at all rice genotypes were totally free from stem borer damage and results showed significant differences (P< 0.05) for the selected traits. These results demonstrated that evaluation of rice genotypes conducted for stem borer tolerance showed resistance reactions by the genomes, viz., Basmati-15-15, Jajai-25/A, Basmati-15-13 and CR-33. These four genotypes possessed better antixenosis against adult egg laying and antibiosis for larval survival of stem borer as compared to the susceptible genome. These genotypes can be used in resistance development breeding program and should be admired in stem borer endemic areas. But, the genotypes Basmati- 20-300, Basmati-20-400, Basmati-1.5-3 and CR-12 were highly susceptible to borer's incidence with a corresponding reduction of paddy yield. The present study implies that the tolerant elite lines are able to minimize yellow stem borer's damage and could be readily used in breeding program to release aromatic rice varieties with significantly improved paddy yield.