The Effect of Higher Temperatures on Cotton Lint Yield Production and Fiber Quality

An optimal temperature range exists for cotton ( Gossypium hirsutum L.). When Mississippi Delta cotton experiences temperatures above the upper threshold, as can occur during the summer, it is not entirely clear what growth parameters are affected by the heat. The objectives of this study were to document differences in agronomic and physiological performance for two cotton genotypes (SureGrow 125 and SureGrow 125BR) when grown under an ambient temperature control and a warm temperature regime (about 1°C warmer). Field studies were conducted from 2003 through 2005. White bloom counts, nodes above white bloom (NAWB) data, dry matter partitioning data, lint yield, yield components, and fiber quality data were collected. Genotypes responded similarly to the temperature regimes. Warmer temperatures resulted in lower NAWB data, indicating a slightly advanced crop maturity. In two out of three years, the lint yield from the warm regime was 10% lower than that of the control. This reduction was primarily caused by a 6% smaller boll mass, with 7% fewer seed produced per boll in the warm regime. Fiber produced in the warm temperature regime was consistently 3% stronger than fiber in the control treatment. When temperatures become too hot, ovule fertilization may be compromised, leading to fewer seeds produced per boll, smaller boll masses, and ultimately, lint yield reductions.