Two locations were small-plot designs with four replications. All other locations were single strip trials.
Plant growth regulator treatments included two approaches to PGR management, with the PGR used selected by the grower.
— Passive: Standard PGR application schedule and rate for local conditions.
— Aggressive: 1.5 to 2x rate of the passive treatment.
Understanding the Results
Results for analysis of variance indicated that there was no significant interaction for variety x PGR treatment for plant height or lint yield; however, there were numerical differences that were of interest.
PGR treatments were significantly different from one another for plant height whereas varieties were significantly different from one another for lint yield.
Data presented are for numerical differences that were observed for variety x PGR treatments.
DP 1835 B3XF and DP 1916 B3XF were the most responsive for plant height reductions with an aggressive PGR treatment.
DP 1725 B2XF and DP 1851 B3XF were the least responsive for plant height reductions with an aggressive PGR treatment.
An increase in lint yield was observed when applying an aggressive PGR treatment for all cotton varieties tested with the exception of DP 1840 B3XF.
What Does This Mean for Your Farm?
The results from this study demonstrate how PGR treatments can affect cotton varieties differently with respect to growth habit and yield potential.
When selecting cotton varieties to plant, always consider the growth habit of the variety and the type of the environment it will be grown.