Temperature Effects on Early Season Cotton Growth and Development

Abstract

Temperature is a primary environmental factor controlling growth and developmental rates of plants, yet little specific information is available regarding cotton (Gossypium hirsutum L.) responses to temperature. Information covering a wide range of temperatures would be useful for predicting both developmental and growth rates in cotton. Therefore, an experiment was conducted in naturally lit, temperature-and CO,-controUed cabinets from soon after emergence until 56 d after emergence (DAE). The cabinets were maintained at 20/12, 25/17, 30/22, 35/27, and 40/3rc day/night cycles. Plant heights, number of nodes, and leaf areas were determined weekly throughout the experiment, and dry weight measurements were obtained at three intervals. Mainstem elongation, leaf area growth, and biomass accu· mutation rates were very sensitive to temperature about 3 wk after emergence. Prior to that time, they were relatively insensitive to temperature. The temperature optimum for stem elongation, leaf area expansion, and biomass accumulation was 30/2rC. Developmental rates, as depicted by number of mainstem nodes produced, number of fruiting branches, and fruiting branch nodes, were not as sensitive to temperatures above 30/2rC as were growth rates. Four times as many fruiting branches were produced at 30/2rC as at 20/1rC; whereas more vegetative branches were produced at low temperatures. All flower buds (squares) abscised from plants grown at 40/3rC. Essentially, all bolls and squares were retained at 30/22 •c while a 10o/c boll and square loss was observed at 35/27 •c during the early reproductive period. Less time was required for this cultivar to produce squares at any temperature, suitable for growing cotton, than was suggested by previous experiments.

Growth and photosynthesis of Upland and Pima cotton: response to drought and heat stress

“…Many studies reported separately on changes in growth and physiology of cotton genotypes under drought stress (Pace et al 1999, Ullah et al 2008 and heat stress (Reddy et al 1992). However, these stress factors often accompany each other and occasionally appear alone.…”

The effect of high temperature on the insecticidal properties of Bt Cotton

“…Others attributed that production of the toxin is influenced by plant age or reproductive stage, and/or by a variety of environmental factors (Benedict et al, 1993;Wu et al, 1997). High temperature is one of the environmental factors to affect cotton development process (Reddy et al, 1992(Reddy et al, , 1998, the maximum temperature is usually at 36-40 • C, the period of high temperature occur for 6-10 days during cotton growing season in China (Miao et al, 1998;Zhou, 1999), and resulted in senescence of leaves, abscission of bolls and reduced lint yield (Zhou et al, 1996). The field investigation discovered that the reduction of the insect-resistant efficacy for Bt cotton was after high temperature climate.…”

Simulating the impacts of climate change on cotton production in the Mississippi Delta

“…Cultural practices such as earlier planting to enhance yield, will undoubtedly evolve, but this will be limited by available radiation in non-summer periods. Many of the Upland cultivars do not tolerate the high temperatures projected, and the modern Pima cultivars are even more sensitive (Kittock et al 1981, 1988, Reddy et al 1992a,b, 1998b. As a result, strategies for reducing the impacts of climate change on cotton production should focus on developing heat-andcold-and drought-resistant cotton cultivars in order to mitigate the effects of climate change.…”