Impacts of varying day and night environmental conditions on cotton flowering, yield, and fiber quality

Authors: THENVEETTIL, NAFLATH - Mississippi State University; ALLAM, MANOJ K - Mississippi State University; Anapalli, Saseendran; Reddy, Krishna; GAO, WEI - Colorado State University; REDDY, RAJA - Mississippi State University

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/17/2025
Publication Date: 10/2/2025
Citation: Thenveettil, N., Allam, M.R., Anapalli, S.S., Reddy, K.N., Gao, W., Reddy, R.K. 2025. Impacts of varying day and night environmental conditions on cotton flowering, yield, and fiber quality. Frontiers in Plant Science. Volume 16 - 2025. https://doi.org/10.3389/fpls.2025.1616982.
DOI: https://doi.org/10.3389/fpls.2025.1616982

Interpretive Summary: In 2024, U.S. cotton yield declined by 7% compared to the previous year, largely due to heatwaves, prolonged drought, and other extreme weather events. In this study, scientists from the Crop Production Systems Research Unit, USDA ARS, in collaboration with Mississippi State University in Starkville, MS, examined how variations in air temperature and CO2 concentrations influence cotton lint and seed yield using controlled Soil–Plant–Atmospheric Research chambers. Significant differences were observed in reproductive traits, seed production characteristics, and plant phenology across environmental treatments. Elevated air temperatures accelerated boll opening by 1–2 days and increased boll shedding, ultimately reducing both seed and lint yields. These findings underscore cotton’s vulnerability to temperature fluctuations and the resulting impacts on regional productivity. The study highlights the need for improved agronomic management strategies to mitigate the effects of environmental extremes on cotton production. This research directly supports the Secretary of Agriculture’s priority to enhance the profitability and stability of crop production systems for farmers and ranchers.

Technical Abstract: Increases in the frequency of higher-than-optimum air temperatures can substantially reduce cotton production. This study examined the impacts of air temperature variations on the morphology of cotton flowers and seed yield under air CO2 concentrations at 425 ppm (ambient, aCO2) and elevated at 725 ppm (eCO2) in controlled Soil-Plant Atmospheric Research (SPAR) chambers. The four temperature conditions were: optimum (OT; 33/21°C, day/night), high temperature (HT; 36/24°C, day/night), high nighttime (OT+HNT; 33/24°C, day/night), and high day/nighttime (HT+HNT; 36/28°C, day/night). Various reproductive and seed yield traits, as well as the phenology of the plants, differed significantly (p < 0.001) under the treatments. The boll maturation period significantly decreased in plants grown under HT+HNT, with only 39 days under aCO2 and 38 days under eCO2 compared to 47 days at OT. In the HT and OT+HNT conditions, the duration was 42 days at aCO2 and 46 days at eCO2, as opposed to 41 and 44 days, respectively, under aCO2. Furthermore, there was a significant reduction in the number of pollen grains per anther, 13% for OT+HNT, 24% for HT, and 39% for HT+HNT, relative to OT treatments. The seed cotton weight also showed a drastic decline, decreasing from 105 g plant-1 under OT to 90 g under OT+HNT, 47 g under HT, and 12 g plant-1 under HT+HNT conditions. In the HT+HNT environment, lint percentage and seed weight per plant were reduced by 26% and 86%, respectively, when compared to OT. The eCO2 did not alleviate the reductions in cotton yield caused by higher air temperature exposure.