ABSTRACT

Replicated cotton variety trials were conducted from 1996 to 2002 in both dryland and irrigated fields. The trials are an important showcase for new varieties and are used by producers to make varietal selections. With the Southern Rolling Plains (SRP) being declared functionally eradicated in 2000, secondary pests like bollworm (Helicoverpa zea (Boddie)) have become less of a problem. The decline in bollworm problems would seem to lessen the value of cotton varieties containing the Bt (Bacillus thuringiensis) gene. However, even under reduced insect pressure, varieties containing the Bt gene Bollgard^® perform well in variety tests. The increased yields are partially due to insect control but primarily are a function of improved varieties. Producers in the SRP should make their variety choices based on yield and fiber qualities. The addition of the Bt gene should be considered a type of insurance. For irrigated producers, the Bt gene represents a low risk management tool where the payoff is high and the loss is low. For dryland producers, the payoff is not as high but the loss is still low.