Influence of Maturity and Fruit Yield on Susceptibility of Peanut to Cercosporidium personatum (Late Leafspot Pathogen)1

Abstract

Abstract A positive relationship between both low pod yield and late maturity of peanut (Arachis hypogaea L.) with resistance to leafspot (Cercospora arachidicola Hori and Cercosporidium personatum (Berk & Curt.) Deighton) has been observed in breeding material and germplasm. To study this association, three peanut genotypes (Early Bunch, Florunner, and Dixie Runner) varying in maturity and yield potential were grown both with and without fungicide spray. Lower yield and later maturity treatments were further imposed on these genotypes through floral bud removal. Removal of floral buds resulted in less leafspot injury, as measured by lesion number per leaf or by a leaf retention score. There was a significant cultivar × treatment interaction. Removal of floral buds significantly reduced pod yield for Early Bunch. The use of chlorothalonil improved yields for Early Bunch and Florunner, but not for Dixie Runner. The proportion of sound mature kernels was increased in Florunner and decreased in Early Bunch by the floral bud removal treatment with no fungicide. Trends for yield of sound mature kernels were similar to those of pod yields. The improved resistance, delayed maturity, and lower yield of treatments with floral bud removal may explain the association noted among three traits in breeding material.