Water Use, Yield, and Fiber Quality Differences of Diverse Cotton (Gossypium spp.) Genotypes

Declining levels of available water for irrigation use in the Ogallala, TX, San Joaquin Valley, CA, and other aquifers has led to the need to identify and develop cotton (Gossypium spp.) cultivars that can more efficiently use available soil water. Elite upland (G. hirsutum L.) commercial cultivars, and Upland and Pima (G. barbadense L.) germplasm representing diverse genotypes and phenotypes were grown on the Texas High Plains under three subsurface drip irrigation levels during two growing seasons. Each entry was planted in four-row plots in a RCBD, with four replications within each irrigation level. Soil water content was measured using a neutron probe throughout the growing season to evaluate differences in water use and water use patterns among genotypes or phenotypes. Plant response to stress was determined based on plant mapping, stripper harvested lint yields and fiber quality parameters. Water use by genotypes was found to respond differently to differing water levels established by drip irrigation. In addition, upland and Pima cotton differed with respect to total water use and water use patterns with soil depth. The greatest water use was observed for the highest irrigation level with proportionately more water and with more water being used after peak bloom rather than before. These results are a first step in identifying cotton phenology’s and cultivars that have the greatest potential to efficiently use water and prolong the availability of water for irrigation.