Determining the effects of irrigation on cotton maturity through vertical distribution

Cotton maturity affects growth and development as well as water use efficiency of the crop. With the continuing depletion to the Ogallala Aquifer, the main source of irrigation water for cotton in West Texas. Maturity characteristics under varying levels of water deficit are becoming more critical to overall yield and the final quality of the crop. In-season and post-season methods of crop maturity estimation were tested to determine the interaction between cultivar and irrigation levels in determining crop maturity, yield, and fiber quality. Research was conducted on four cultivars (Daltapine 1212 (DP1212), FiberMax 2011 (FM2011), FiberMax 2484 (FM2484), and Phytogen 499 (PHY499)) from 2012 to 2015 at the Quaker Research Farm in Lubbock, Texas. The design each year was a split plot with irrigation as the main plot and cultivar as the split plot, with seven to ten irrigation levels and two to three replicates within each irrigation level. In-season measurements of plant height, total nodes, nodes above first square and nodes above white flower were compared with vertical boll distribution, determined as the nodes at which 10, 25, 50, 75 and 90% of the overall yield was achieved by treatment. It was determined that boll distribution characteristics within a cultivar were relatively stable over the irrigation treatments. Crop maturity was consistent between cultivars and all irrigation treatments. As irrigation increased the mainstem nodes that accumulated the majority of the bolls occurred higher on the plant. With these findings, a standardized maturity classification can be created within the cotton industry, thus allowing seed companies to market their cultivars within the classification. While helping producers and research to be understand the differences between maturities and allowing them to apply irrigation or other production practices with precision.