Cotton Yield and Fiber Quality in Relation to Leaf and Canopy Traits Under Different Irrigation Regimes in Southwest Texas

With the rapid development of new cotton varieties, producers need the updated information about drought tolerance capacity of the available cotton varieties. In this study, we measured leaf and canopy traits of selected 12 cotton varieties in southwest Texas in full- and deficit irrigation regimes over two growing seasons in 2017 and 2018. In each growing season, the measurements were made three times at early flower, peak flower and boll development stages. Measured leaf traits include leaf osmotic potentials, leaf area mass per area and leaf dry matter content. Canopy characteristics include canopy temperature and NDVI, measured using a ground-based phenotyping cart. Upon harvest, seed cotton yield and fiber quality were analyzed and correlated to leaf/canopy characteristics. Data show that reduced irrigation did not affect seed cotton yields, but reduced fiber quality. In particular, fiber strength, length and elongation were reduced significantly under deficit irrigation when compared to full irrigation. Reduced fiber quality was more associated with increased leaf dry matter content (ratio of leaf dry mass to saturate mass) rather than in leaf osmotic potential, or leaf mass per area. The performance of specific cotton varieties was discussed considering dryland vs. irrigated cotton production in southwest Texas.