Description

Abstract: Five Spanish and seven runner peanut (Arachis hypogaea L.) genotypes and five check cultivars were compared for southern blight susceptibility on heavily Sclerotium rolfsii-infested soil. Inoculum density of S. rolfsii at the test site was enhanced by continuous years of residue management. The genotypes derived from crosses with PI 365553 and PI 475871 were selected based on reaction to Pythium pod rot and agronomic performance. Variation for southern blight incidence occurred among lines in both runner and Spanish genotypes. Disease incidence was lower in four runner genotypes, Southern Runner, and TxAG-3 than in Okrun and Florunner. Significantly (p=.05) less disease occurred in one breeding line, Tx855138, than in other Spanish entries. Three-year average yields of runner genotypes ranged to 25% higher than runner cultivars, while Tx855138 averaged 50% higher in yield than Tamnut 74. Over entries, the coefficients of correlation for yield and southern blight incidence, and southern blight incidence and disease discolored pods were not statistically significant.