Planting Date Effect upon Leaf spot Disease and Pod Yield across Years and Peanut Genotypes.

Abstract

During 2012, 2015, and 2018 a set of 18 peanut (Arachis hypogaea L.) genotypes (some common and some different) were used to evaluate the effect of planting dates (April, May, and June) on leaf spot disease and pod yield. Within each year, the same genotypes were grown during the three planting dates at the Gibbs Farm near the University of Georgia, Coastal Plain Experiment Station, Tifton, GA using a randomized complete block design with five replications without fungicides or insecticides but with irrigation. Each year, significant differences (P≤0.05) were found among the genotypes within each of these three planting dates for leaf spot disease ratings (0-9 scale) and pod yields. ‘Georganic’ in 2012 and 2015; and GA 132705, ‘Georgia-19HP’, and ‘Georgia-14N’ in 2018 had among the lowest leaf spot ratings. ‘Georgia-12Y’ had the highest average pod yield for each year of the three years. Each year during this study, the April planting date had the lowest, and the June planting date had the highest leaf spot disease ratings. Percent coefficient of variation (CV) was consistently lower at the June planting date which suggest the least variability among the peanut genotypes. In the overall average of genotypes, the April planting date resulted in the highest pod yield and the June planting date had the lowest average pod yield. In summary, April planting dates resulted in the highest pod yields, and the lowest leaf spot ratings across each of the three years.