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ARS Home » Plains Area » Stillwater, Oklahoma » Wheat, Peanut, and Other Field Crops Research » Research » Research Project #424759

Research Project: Development of Improved Peanut Cultivars and Germplasm for the Southwest Peanut Region of the United States

Location: Wheat, Peanut, and Other Field Crops Research

Project Number: 3072-21220-007-000-D
Project Type: In-House Appropriated

Start Date: Feb 5, 2013
End Date: Jan 30, 2018

The long-term objective of this research is to develop and release high oleic peanut cultivars with superior oil chemistry, disease resistance, and agronomic performance. Over the next 5 years this research proposal will address the following objectives: Objective 1: Employ the most up-to-date genotyping, phenotyping, and marker-assisted selection strategies to develop and release superior peanut cultivars containing the most current disease resistance, agronomic, and quality trait genes, with emphasis on high yield, early maturity, oil, and seed quality traits. Subobjective 1A: Develop and release high-oleic, high-yielding runner, Virginia, and Spanish peanut cultivars with superior resistance to Sclerotinia blight, southern blight, and pod rot that are adapted for production in the SW United States. Subobjective 1B: Develop and map molecular markers associated with disease resistance in peanut that will aid in marker-assisted breeding. Objective 2: Improve existing methods and/or develop new methods to screen for resistance to Sclerotinia and southern blights and pod rot of peanut, and use these methods to identify useful resistance genes from the USDA peanut germplasm collection and other sources. Subobjective 2A: Define relationships between resistance to Sclerotinia and southern blights and response to oxalic acid, stem lignin content, and plant architecture characteristics. Subobjective 2B: Develop a reproducible greenhouse protocol for screening germplasm for resistance to pod rot.

Objective 1: Parental lines being used in such crosses include Arachis hypogaea L. cultivars, advanced breeding lines, and plant introductions (PIs) with demonstrated disease resistance and high oleic acid content. New and existing potential parent lines with high oleic acid content are continually tested in the greenhouse and field plots for resistance to Sclerotinia blight and southern blight and are readily available for use in the peanut breeding program. Included in our annual screening of germplasm for disease resistance are cultivars, breeding lines, and germplasm accessions. Also, collaborators include the curator of the U.S. peanut germplasm collection as well as other breeders who are continually evaluating accessions for value added traits. Molecular markers for Sclerotinia resistance will be identified and verified by phenotypic reaction. Advanced breeding lines will be tested in local, regional and national tests for agronomic performance before release as a variety. Objective 2: Response to oxalic acid, stem lignin content, and specific canopy architecture appear to be correlated with Sclerotinia resistance among cultivars of other legumes. We will determine if these traits are also useful for predicting resistance to Sclerotinia and southern blights in peanuts. Development of pod rot-resistant cultivars is significantly slowed by unpredictability of the disease occurring under field conditions. We will develop a reproducible greenhouse protocol for screening germplasm for resistance to pod rot by: 1) identifying and quantifying Pythium spp. and Rhizoctonia solani from Oklahoma and Texas fields with high incidences of pod rot using quantitative real-time PCR; and 2) evaluating symptoms in greenhouse-grown pods exposed to different inoculum levels of the three most common pod rot pathogens found in Oklahoma and Texas.