Effectiveness of Frego Bract as a Boll Weevil Resistance Character in Cotton
1971
Jenkins, Johnie N. | Parrott, W. L.
In 1970 four farms located in different parts of Mississippi each were planted to 4 to 8 ha of cotton (Gossypium hirsutum L.), homozygous for frego bract (fg fg), and to an approximately equivalent acreage of a nonfrego commercial variety. Cottons with frego bract have shown resistance to boll weevils (Anthonomus grandis Boh.) when grown in small plots. Our 1970 tests were designed to measure the cumulative effects of a fregobract cotton, designated M-64, on boll weevil populations when this cotton was grown in large acreages and when the resistance was measured over three or four insect generations. Results from these tests will be used to assess the role of cottons resistant to boll weevil in an integrated approach designed to eradicate this insect. A pilot scale boll weevil eradication program is now underway in Mississippi. In the frego-bract cotton boll weevil oviposition, an indirect measure of population, was suppressed 66, 71, 75, and 94y0 below that in the nonfrego varieties. The variation in suppression was due to different numbers of overwintering weevils and to various control measures used during the season. On two farms no insecticides were required for boll weevil control in the frego-bract strain. The frego-bract strain suppressed the population 94y0 on the farm with the smallest number of overwintering weevils. Thus, oviposition suppression was greatest where it can be of the most use in an eradication program. Fiber properties and yields of the frego strain were adequate for a nonbiased test of the boll weevil resistance attributed to frego bract.
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