Categorization of resistance against the fall armyworm, Spodoptera frugiperda (JE Smith) in select maize inbred lines

Seven maize inbred lines were evaluated for resistance against fall armyworm, Spodoptera frugiperda (J.E. Smith). Non-preference for oviposition in no- and multi-choice tests and feeding non-preference of neonates in multichoice test was observed in lines CML 338, CM 500 and CML 72. Antibiosis was observed in CML 338, CML 72 and CML 71, in terms of significantly prolonged larval period (18.22-19.56 days), lower larval (111.52-131.80 mg) and pupal weights (105.65-127.67 mg), shorter adult longevity and lower fecundity as compared to susceptible inbred lines, BML 6 and LM 24. Larvae fed on CML 338 and CML 71 had significantly higher mortality and lower nutritional indices. Significantly higher foliar damage rating was observed on younger plants (10 days old) in all test inbred lines, as compared to older plants (20 and 30 days old) during 2020 and 2021. The mean foliar damage rating by fall armyworm larvae varied significantly among the test inbred lines being significantly lower in CML 338 and CML 71 compared to BML 6 and CM 500 that had higher damage at all crop stages when recorded at 7, 14 and 21 days after release. Functional Plant Loss Index (FPLI) was significantly lower in CML 338 and CML 71 (12.18-18.58%) followed by CML 72 (24.87%). Regression of FPLI on fall armyworm larval dry weight indicated presence of antibiosis and tolerance in CML 338, CML 71 and CML 72 towards fall armyworm. Overall, maize inbred lines CML 338, CML 71 and CML 72 with moderate resistance may be used for resistance breeding programme against this insect pest.