Studies on the tolerance mechanism in selected rice accession against yellow stem borer, Scirpophaga incertulas (Walker)

Investigation on the tolerance reaction of selected rice accessions against yellow stem borer (YSB) indicated that IET 23715 showed moderately resistant with rating scale of 3 followed by both IET 23694 and IET 23272 showed moderately susceptible with rating scale of 5, while IET 23673 and IET 23681 showed susceptible category with rating scale of 7 as against TN 1 registered the rating scale of 9. The yield attributing characters viz., per cent reduction in grain yield/hill, no. of grains/ panicle, 1000 grain weight and per cent increase in chaffy grains in infested plants over healthy plants of the respective test accessions were recorded. Among the accessions, per cent yield reduction was lowest in IET 23694 followed by IET 23715, IET 23272, IET 23681 and IET 23673, whereas percent reduction in panicle length, grains/panicle, 1000 grain and increase in chaffy grains were lowest in IET 23715 followed by IET 23694 and IET 23272. However, IET 23673 recorded the highest percent reduction in panicle length, grains/panicle, 1000 grain and increase in chaffy grains.