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Title: REACTION OF PEANUT GENOTYPES TO SCLEROTINIA BLIGHT IN FIELD PLOTS (MODIFY TITLE, ADD ACC DATE)

Author
item AKEM, CHRIS - OKLAHOMA STATE UNIVERSITY
item Melouk, Hassan
item SMITH, OLIN - TEXAS A&M UNIVERSITY

Submitted to: Fitopatologia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/21/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Outbreaks of sclerotinia blight disease, caused by the fungus Sclerotinia minor, in peanut in Oklahoma, Texas, Virginia, and North Carolina result in significant yield losses. Management of sclerotinia blight by chemicals is expensive and often does not provide acceptable control. Therefore, the objective of this research was to identify sclerotinia-resistant sources in nthe peanut germplasm. This paper discusses the results of a 3-year study i which the sclerotinia blight reaction of several peanut lines from the breeding program at Texas A&M University was determined in field plots. Several peanut lines were identified as resistant to the sclerotinia pathogen. A selection of one of these lines (PI 798736) was released in 1990 by Texas A&M and the Agricultural Research Service as sclerotinia- resistant peanut cultivar 'Tamspan 90'.

Technical Abstract: Nineteen peanut (Arachis hypogaea) genotypes were evaluated in Sclerotinia minor-infested field plots at Stillwater, OK, USA, for reaction to Sclerotinia blight in 1986, 1987, and 1988. After digging, plants were separated into infected and non-infected groups and stored on greenhouse benches to dry. Number of pods per plant from each genotype was determined from randomly selected plants in each disease category to determine the effect of S. minor on pod yield of the lines. Viability of sclerotia collected from randomly selected stem segments and pods of susceptible lines was determined by germinating sclerotia on potato dextrose agar containing 100 mg/l streptomycin sulfate (SPDA) at 25 +/- 2 deg C in darkness. Sclerotia collected from stems were significantly more viable than those collected from pods of susceptible genotypes. Highest sclerotial viability was 82% from stems of cultivar Tamnut 74, and 60% from pods of Florunner. Lowest was 29% from stems and 13% from pods on genotypes TX 771174 and TX 835841, respectively. No sclerotia were produced on resistant genotypes.