Simulating Climate-Change-Adaptive Cultivars for Sustaining Cotton Production in the Texas High Plains

Texas High Plains (THP) is a major cotton producing region in the United States, producing about 4 million bales of cotton annually. Sustaining cotton production under declining groundwater availability and changing climate remains a key challenge for stakeholders in the THP region. In this study, we used a popular crop growth model, DSSAT-CSM-CROPGRO-Cotton, for simulating cotton production under 18 projected future climate scenarios with six potential adaptation measures at three locations, namely Bushland, Halfway, and Lamesa in the northern, central and southern parts of the THP, respectively. Seed cotton yield and irrigation water use between the baseline (1976–2005) and future periods (2036–2065 and 2066–2095) were compared. Results showed that cotton yield could benefit from the increasing atmospheric CO₂ levels in the northern THP, while the southern sites with lower soil water holding capacity would likely face decline in irrigated cotton yield due to temperature rise. Cotton water demand, however, increased in the future at all locations, likely due to increased leaf area and biomass due to CO₂ fertilization effect. The average increase in irrigated cotton yield was 19% at the two northern locations, and average decrease in yield at the southern site was 4%. The average increase in irrigation water demand across locations and future periods was 12%. The potential adaptations were designed by changing genetic traits of the baseline cultivar and they were tested for drought tolerance, heat tolerance, high yield potential, and longer maturity. Increasing area of full leaf, enhancing partitioning of assimilates to reproductive growth (high yield potential), and increasing root length per unit root weight (drought tolerance) were identified as desirable climate-change-adaptive traits for irrigated cotton production in the THP region. The cultivars with high yield potential and drought tolerance traits had 7% higher average irrigated yield than the cultivars without those genetic adaptations.