Breeding Implications of Boll Distribution Responses to Water Stress Deficits in Upland Cotton (Gossypium hirsutum L.).

To identify the impact of different water stress deficits on the boll distribution of elite Upland cotton (Gossypium hirsutum L.) cultivars in the Texas High Plains, cultivars which represent the diverse gene-pools of the private sector were subjected to three different water deficit regimes. This study had four row plots (7.62 meters) per entry arranged in a RCBD with three replications in 2013 and four replications in 2014 under subsurface drip irrigation. Analyses of boll distribution revealed that there were significant differences (P ≤ 0.05) between boll distribution and position of all cultivars across all water levels and cultivars within each water rate. First and second position bolls contributed the most to yield under all irrigation levels. This suggests that certain cultivars will be more beneficial under one irrigation then another. These findings also suggest that certain cultivars may perform well under multiple irrigation levels. Cultivars also revealed unique patterns of boll distribution and retention under different water stress deficits. This indicates that certain environmental conditions may be responsible for boll distribution and retention of bolls. However, the genetic potential of breeding for specific fruiting habits may be able to overcome yield reductions due to water deficits.