Genotype‐Environment Interaction Study of Lock Tenacity in Upland Cotton1

Abstract

Sixteen upland cotton (Gossypium hirsutum L.) cultivars were grown in replicated experiments under irrigation and on dryland at each of two Oklahoma locations over a 3‐year period. The storm resistance trait, measured as “lock tenacity”, was studied in genotype ✕ environment interaction analyses over years for all four experiments, for the two irrigated tests, and for the two dryland tests to estimate those interactions and to consider their implications relative to the cotton breeding and cultivar evaluation programs within the state.A number of genotype ✕ environment interaction mean squares for lock tenacity were significant for both observed and log‐transformed data; however, the magnitudes of the interaction variance components were relatively small compared to their respective cultivar components and were concluded to be of minimal importance in the determination of the trait. Classifications into major bolltype categories and selections for the trait in one environment should be relatively stable in other environments. However, because the range of values observed was greater under irrigation than on dryland and because the separation of boll types was more distinct, more effective selections for the trait are probably made under irrigation.