Genetic and Environmental Contributions to Cotton Yield and Fiber Quality in the Midsouth

Producers need to know the contributions of genotype (G), environment (E), and their interaction (GxE) in determining cotton (Gossypium hirsutum, L.) lint yield, lint percentage and fiber quality.  The recent introduction of longer upper half mean length (UHML) fiber, lower micronaire cultivars may alter previously defined contributions.  The objectives of this research were to: define the G, E and GxE contributions to lint yield, lint percentage and fiber quality from common-cultivars evaluated within the U.S. MidSouth and define shifts in these contributions caused by the introduction of a longer UHML, lower micronaire cultivar.  Data from 102 large-plot trials within AL, AR, LA, MS, MO and TN were compiled from the 2015 and 2016 seasons; 85 site-years contained three common-cultivars and 69 contained four common-cultivars.  Analysis of three common-cultivars within the 69 site-year dataset indicated E dominated factors of lint yield (85.8%), lint percentage (88.5%), micronaire (70.9%), length (70.5%) and uniformity (70.4%).  Large increases in the contribution of G to micronaire (26.0%) and length (37.6%) were observed when the lower micronaire, longer UHML cultivar was included.  The relatively minor role of cultivar in determining lint yield and the substantial role of cultivar in determining micronaire and length suggests producers within the MidSouth should begin to place more importance on fiber quality data when selecting cultivars.