Resistance in hybrid derivatives of Lycopersicon accessions against leaf caterpillar, Spodoptera litura Fab.

Four tomato accessions, namely Ac 238, Roma, Seijima Jeisei and Varushanadu Local selected from preliminary screening of 321 accessions and their hybrid derivatives, namely HY1F1 (Varushanadu Local x Ac 238), HY2F1 (Varushanadu Local x Roma), HY3F1 (Ac 238 x Roma) (first generation), HY1F2, HY2F2 and HY3F2 (second generation) were evaluated for their resistance in comparison with a susceptible check, 1979 against the leaf caterpillar, Spodoptera litura Fab. both under field and laboratory conditions at Annamalainagar, Tamil Nadu, India. In the field evaluation, accession Seijima Jeisei and hybrid HY3F1 recorded the minimum larval population. In glasshouse and laboratory studies, Seijima Jeisei was the least preferred by S. litura for both feeding and oviposition. The hybrid HY3F1 exerted pronounced antibiosis effect on S. litura. Among the various biophysical and biochemical bases of resistance, contents of reducing sugar and phenol were found negatively correlated with S. litura larval feeding. Among the hybrids, HY3F1 and HY3F2 and the parent Seijima Jeisei recorded higher fruit yield per plant in both seasons. Considerable variation in the resistance traits of the hybrids was observed when compared with the parents.