Reevaluation of the degree day base 60°F concept in US cotton (Gossypium hirsutum L.) production

Cotton (Gossypium hirsutum L.) management decisions to abet early growth, fruit set, boll maturation, and harvest preparation are often facilitated by prediction of the date when critical developmental stages are reached. In the United States, growing degree days calculated with a base 60°F (DD60s) are commonly used to predict cotton development. Observations suggest development of modern cultivars differs from previously established guidelines. The objectives were to (1) reevaluate DD60s required for an early, mid‐maturing and late maturing cultivar to reach key growth stages across the US Cotton Belt; and (2) determine if predictions of growth stages are strengthened by optimizing base temperature or including an upper threshold by growth stage. During 2018 and 2019, 22 field trials were established in 10 states. This dataset includes dates at which each plot at each trial location reached a given growth stage; location latitude, longitude and soil type.