Antibiotic effect of insect-resistant soybean [Glycine max] on common cutworm (Spodoptera litura) and its inheritance

The common cutworm (Spodoptera litura Fabricius; Lepidoptera: Noctuidae) is a menace to soybean (Glycine max (L.) Merr.) production in southwestern Japan. We have been evaluating soybean germplasm for resistance to common cutworm in order to develop resistant cultivars and have found a cultivar named ‘Himeshirazu’, which is distinguished by its high level of resistance. We compared the antibiosis of Himeshirazu with those of ‘Fukuyutaka’ (susceptible) and ‘Sodendaizu’ (resistant). Himeshirazu depressed the weights of individual common cutworm larvae and prolonged the duration of the instar stage, compared with the other two cultivars. We analyzed the inheritance of this antibiosis in an F2 population derived from a cross between Fukuyutaka and Himeshirazu. The broad-sense heritability of the antibiosis was estimated as 71.3 %. The segregation pattern in the F2 progeny suggested that a recessive factor controlled a considerable part of the antibiosis. From the relationship between the antibiosis and the genotype of a simple sequence repeat marker, Satt220, in the F2 progeny, we inferred that the locus of the putative recessive factor was located on linkage group M.