Identifying seed cotton yield and abiotic stress response in cotton (Gossypium hirsutum L.) grown in the Arizona low desert

Cotton (Gossypium sp.) is an important natural fiber crop that supports a multi-billion-dollar textile industry worldwide. Improved breeding strategies are needed to develop heat- and drought-tolerant cotton. Six upland cotton entries were grown in the Arizona low desert at the Maricopa Agricultural Center, and seed cotton yields were recorded. Cotton responses to abiotic stressors, including high heat and low soil water content, were estimated from leaf chlorophyll and nitrogen content and chlorophyll fluorescence throughout the growing season. Statistical analysis identified important relationships and temporal patterns between the measured traits within each cotton entry. The data showed that leaf chlorophyll and nitrogen content and chlorophyll fluorescence can indicate degrees of abiotic stress tolerance along with improved seed cotton yields. These results agree with previous reports that low and stable leaf chlorophyll content and increased photochemical efficiency during heat stress are indicators of thermotolerance in cotton. The data also indicate that measurements collected just before and during peak flower are most informative for breeding programs when compared to a control.