Cotton boll distribution, yield, and fiber quality in response to irrigation

Cotton is one of the main crops produced on the High Plains of Texas. Because of the limited heat and growing season available in the high plains, maturity is critical to both yield and fiber quality of the cotton crop. A cotton plant produces fruit at regular intervals on adjacent fruiting sites up the plant; therefore, the maturity characteristics of a cultivar are tied to the distribution of bolls on the plant. However, a given cultivar may not show the same growth habits under different environmental conditions, such as irrigation rate. This study compares the effects of multiple deficit irrigation levels on within plant boll distribution, yield, and fiber quality of five different varieties: FiberMax 1830GLT (FM1830), FiberMax 2011GT (FM1830), FiberMax 2334GLT (FM2334), Stoneville 4747GLB2 (ST4747), and Stoneville 4946GLB2 (ST4946). The cotton was grown at the Texas Tech Quaker Research Farm in Lubbock, TX in 2014 and 2015. At harvest, two rows of each plot were harvested with a cotton stripper and the plots were weighed. A subsample of each plot was ginned, and lint yield and fiber quality were determined. For both years of research, irrigation level had a statistically significant effect on lint yield, length, uniformity, and strength. Cultivar also had a significant impact on lint yield, length, uniformity, strength, and bolls per plant. Cultivar had a significant effect on micronaire for 2014 but not 2015. The interaction of cultivar and irrigation level was not significant for either year of the study. FM1830 had the longest length for 2014, and FM2334 had the longest length in 2015. FM1830 and FM2334 were most uniform for 2014 and 2015. FM 1830 had the greatest strength for 2014 and 2015. FM2334 had the highest micronaire for 2014.