ABSTRACT
The objective of this study was to evaluate cotton cultivars based on the compensatory increase of cotton squares in response to the simulation of the boll weevil damage. The first experiment aimed to evaluate cotton cultivars with greater compensatory increase in squares removed artificially from the plant. The experimental design was in randomized blocks, in a 4 × 2 factorial scheme with 100% removal of cotton squares at 50, 70 and 90 days after the emergence of the FM975WS, TMG81WS, IMA6501B2RF and BRS432B2RF cotton cultivars and passive production (without removal) and active (with removal) of cotton squares, with four replications. In the second experiment, boll weevil damage in the TMG80WS and BRS432B2RF, with greater and lesser compensatory increase of cotton squares, after their removal at 50 days of age, was evaluated. The experimental design was in randomized blocks, in a 2 × 2 factorial scheme, with the former cultivars sprayed with carbamate or not (control). The compensatory increase of cotton squares, mainly after their artificial removal at 50 and 70 days of age, of the TMG81WS, was greater. The cotton square compensatory increase after being artificially removed in the cotton cultivars was higher during the period of exponential production of these reproductive structures and can be used to select cultivars tolerant to boll weevil damage.
Key words
Anthonomus grandis
;
Gossypium hirsutum
; plant resistance to insects; tolerance
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Note. Means followed by the same lowercase letter, per bar and date do not differ between cotton cultivars by the Student–Newman–Keuls test at 5% probability. Means transformed into vx + 0.5 for statistical analysis. Original means are shown.
Note. Means followed by the same lowercase letter, by bar and date, do not differ between cotton cultivars by the Student–Newman–Keuls test at 5% probability. Averages transformed into vx + 0.5 for the purposes of statistical analysis. Original means are shown.
Note. Means followed by the same lowercase letter, by cultivar and date, or uppercase, by type of production and date, do not differ by the Student–Newman–Keuls test at 5% probability. Means transformed into vx + 0.5 for statistical analysis. Original means are shown.
Note. Means followed by the same lowercase letter, by bar and date, do not differ between cotton cultivars by the Student–Newman–Keuls test at 5% probability.