Lint Yield, Earliness and Pink Bollworm Resistance of Cottons Treated with Ethephon and Untreated

Abstract

An early -maturing, nectariless, okra-leaf germplasm line of cotton, Gossypium hirsutum L., designated WC-12NL, was compared with a full- season, nectaried, regular -leaf cultivar, 'Deltapine 61' (DPL-61) over two locations, Maricopa, Arizona (AZ) and Brawley, California (CA), and two seasons, 1986 and 1987. Half of each plot was treated with ethephon ( =Prep) when the crop was approximately 60% open. Lint yields were higher in WC-12NL than in DPL-61 at AZ, but not at CA. WC-12NL was earlier maturing than DPL-61, but the difference was greater in untreated than in ethephon-treated plots and at AZ than at CA. From 33 to 67% less insecticide was needed to control pink bollworm, Pectinophora gossypiella (Saunders), on WC-12NL than on DPL-61. Pink bollworm infestations were also significantly lower in bolls of WC-12NL.