Multiple Insect Resistance in Several Soybean Genotypes1

Abstract

Three commercial soybean [Glycine max (L.) Merr] cultivars and two breeding lines were evaluated for levels of resistance to four insect species. ‘Centennial’, ‘Forrest’, and ‘Tracy‐M’ and the advanced breeding lines D75‐10169 and D75‐12035 were compared to the insect resistant plant introduction (PI) 229358 for levels of resistance to velvetbean caterpillar (Anticarsia gemmatalis Hübner), soybean looper [Pseudoplusia includens (Walker)], tobacco budworm [Heliothis virescens (Fabricius)], and corn earworm [Heliothis zea (Boddie)]. Three tests were conducted in two environments. Average weights of lepidopteran larvae reared on leaves from the five genotypes were greater than those reared on leaves from PI 229358 by 6.3, 24.4, 43.3, 73.6, and 92.7% for D75‐10169, D75‐12035, Tracy‐M, Forrest, and Centennial, respectively. Each plant genotype showing resistance to one of the insect species also showed resistance to the other three species evaluated. Thus, the development of cultivars from PI 229358 with resistance to several insect species may be possible without the costly and time‐consuming process of screening each insect species at each selection stage in a breeding program. The use of cultivars with intermediate levels of resistance as adapted parents in crosses with resistant germplasm may facilitate the development of highly resistant and agronomically desirable soybean genotypes.