Variation in Yield and Resistance to Southern Stem Rot Among Peanut (Arachis hypogaea L.) Lines Selected for Pythium Pod Rot Resistance1

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.

Seeding Rate, Irrigation, and Cultivar Effects on Tomato Spotted Wilt, Rust, and Southern Blight Diseases of Peanut1

“…Curtis) Deighton, was found to have partial resistance to rust caused by Puccinia arachidis Speg. (3) and southern blight caused by Sclerotium rolfsii Sacco (12). GK-7 was a predominant cultivar grown in southwestern Texas in the early 1990s.…”

Management ofSclerotium rolfsii‐caused stem and pod rots of groundnut—a critical review†

“…Although no genotypes are known to be immune or even highly resistant to S. rolfsii, several genotypes and breeding lines have been found to show lower than average susceptibility to stem rot'pod rot under field conditions (Wynne and Beute, 1983;Beute etal., 1986;Arnold etal., 1988;Smith et al, 1989;Brenneman etal., 1990;Grichar and Smith, 1992). Of several genotypes reported as partially resistant (NC 2, NC Ac 18016, NC8C, Toalson and Southern Runner), resistance of Toalson has been confirmed by several researchers (Simpson etal., 1979, Branch andCsinos, 1987;Smith etal., 1989).…”

“…Data from most studies suggested that differences in susceptibility to stem rot were actually related to growth habit; the semidecumbent or bunch types being more susceptible than the runner types. Some recent studies have supported these observations (Grichar and Smith, 1992). However, Branch and Csinos (1987) observed that as a group, Spanish types were less susceptible than other types.…”

“…T x Ag-3) recently developed at the Texas A.&M. University, USA, are more resistant than Toalson (Smith etal., 1989). T x Ag-3 has consistently shown low stem rot incidence, and has resistance to Pythium myriofy/um-caused pod rot (Grichar and Smith, 1992). This line is a selection from PI 365553 (introduced from Honduras) which has multiple resistance to P. myriotylum, ft solani, and the lesion nematode Pratylenchus brachyurus.…”

“…For pod rot evaluations, early workers used a 0 to 4 scale where 0 = no pod rot symptoms and 4 = 51-100% surface area of pods damaged (Cooper, 1961). In more recent studies (Smith etal., 1989;Grichar and Smith, 1992), a 0 to 10 scale has been used where 0 = no disease symptoms and 10 = pods completely rotted. †Submitted as Journal Article No.…”