Screening Cotton Germplasm for Resistance to the Herbicide Acifluorfen

S.R. Oakley, B.A. Waddle, and R.E. Frans


 
ABSTRACT

The identification of cotton (G ossypi um hirsutum L.) lines resistant to the soybean herbicide acifluorfen (an effective postemergence herbicide for selective control of morningglory and other broadleaf weed species) may allow the development of over-top selective broadleaf weed control programs for cotton producers. The availability of acifluorfen resistant cotton lines would be a significant step toward an IPM approach for control of cotton broadleaf weed pests, and may enable weed scientists to control broadleaf weed pests on an "as needed" basis instead of the almost "automatic" approach in current cotton preemergence herbicide programs. The objectives of this research were to evaluate a selection of cotton lines for resistance to acifluorfen, develop an in vitro assay for acifluorfen resistance in cotton, and to characterize the inheritance of identified acifluorfen resistance.

In 1981 and 1982 over 400 lines of cotton germplasm from the cotton collection at Stoneville, MS were evaluated for acifluorfen resistance in field trials. In 1983 and 1984,25 lines were selected and evaluated under five levels of acifluorfen (0, 0.17, 0.33, 0.5, and 0.67 kg/ha ai postemergence over-top) applied at the V7 stage (20 to 25 cm tall). As a result, the following Stoneville lines have been identified as having potential resistance to acifluorfen: SA no.'s 633, 164, 384, 281, 151, and 112. The potential for acifluorfen resistance in these lines was confirmed by an in vitro radio-labeled leaf disk test. This assay is based on the Principal that cotton leaf disks readily take up 4C-Iabeled methyl-glucose from solution, and when the leaf disks are exposed to herbicide, differences in sensitivity can be observed by measuring radiolabel leakage through scintillation. Several of the cotton lines involved in the screening project were utilized in a diallel crossing scheme in order to acertain the inheritance of acifluorfen resistance. The results of the inheritance study are not available at this time because of the unusually wet fall and delayed harvest schedule.



Reprinted from 1985 Proceedings: Beltwide Cotton Production Research Conferences pg. 200
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998