Resistance to Boll Weevil in Mixed Populations o Resistant and Susceptible Cotton Plants1

Abstract

The reliability of resistance to attack by boll weevil ( Anthonomus grandis Boh). conferred by the mutant gene, H2 was tested under different environmental conditions, i.e., in different proportions of the mutant strain, Pilose, and the susceptible variety, All-In-One, or in the absence of susceptible plants. In order to carry out this test it was necessary to isolate individual plots from one another using corn as a barrier crop, and to provide a uniform infestation of boll weevils. This method proved satisfactory. The degree of resistance was measured inversely by the proportion of squares with egg-laying punctures. The mutant strain, Pilose, showed a significantly lower proportion of egg-laying punctures throughout the investigation. A slight but consistent increase in number of egg-laying punctures with increased in the resistant strain, Pilose, as well as in the susceptible variety, All-In-One.