Effect of chlorothalonil application frequency on quality factors of peanuts (Arachis hypogaea)
1989
Sanders, Timothy H. | Gorbet, Daniel W. | Shokes, Fred M. | Williams, E Jay | McMeans, Jack L.
Yield, disease rating, seed quality and seed size parameters were determined from four peanut (Arachis hypogaea L) genotypes with different levels of resistance to leafspot to evaluate the effects of controlling peanut leafspot with chlorothalonil. In 1981 and 1983, main plot treatments were (i) no fungicide applications, (ii) applications of chlorothalonil (1242 g ai ha-1) at 14-day intervals, and (iii) applications of chlorothalonil (1242 g ai ha-1) at 20-day intervals. After shelling, a narrow seed size range (less than 8.33 mm less than or equal to 7.14 mm width) was used to reduce maturity effects in analyses of free fatty acids, total carbonyls, carbohydrates, oil content, and fatty acid profile. Oil content increased significantly with spray frequency in both years only in Southern Runner, and treatment differences in all genotypes were no more than 1.7%. Oleic and linoleic acid decreased and increased, respectively, with increased spray frequency in Florunner (susceptible) and the resistant genotype with the highest unsprayed disease rating. Florunner median seed size for the unsprayed treatment (8.07 mm) was significantly smaller than the median sizes for the 20-day interval (8.15 mm) and 14-day interval (8.16 mm) treatments.
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