Development of cotton germplasm for reduced insecticide use production systems

Management of the bollworm (Helicoverpa tea [Boddie]) and tobacco budworm (Heliothis virescens [F.]) complex in cotton (Gossypium hirsutum L.) is a significant production cost and a large contributor of insecticides to the environment. Genetic resistance or tolerance could help alleviate these problems. We conducted a trial to identify and exploit sources of bollworm/tobacco budworm resistance in the Pee Dee (PD) cotton germplasm. The experiment consisted of selecting phenotypically desirable cotton plants in segregating populations when produced with limited control of bollworm/tobacco budworm. Although this methodology had previously been successful in identifying resistant types, we were unable to demonstrate a response to selection. The study did find that PD 0762, a germplasm released as possessing resistance to bollworm/tobacco budworm based on lint yield in limited control experiments, likely is tolerant of square loss as its reaction to this insect complex does not suggest resistance. We also found that a new germplasm PD 0786 has a low level of resistance to bollworm/tobacco budworm and therefore could be a component of sustainable cotton production systems for the USA and developing countries.