Location: Peanut and Small Grains Research Unit
Project Number: 3070-21220-009-000-D
Project Type: In-House Appropriated
Start Date: Jan 31, 2023
End Date: Jan 30, 2028
Objective:
Objective 1. Conduct research to identify new molecular markers for disease resistance, use the information to develop and phenotype recombinant inbred line populations, and develop peanut cultivars with improved disease resistance.
Subobjective 1.A: Develop a RIL population for mapping resistance to Pythium pod rot. Subobjective 1.B: Phenotype and genotype RIL populations developed for mapping markers for resistance to Sclerotinia blight, peanut smut, and Pythium pod rot. Subobjective 1.C: Analyze phenotypic and genotypic data collected in Subobjectives 1.A and 1.B to identify possible QTL for disease resistance and design molecular markers to be used in MAS breeding.
Objective 2. Identify new sources of resistance to peanut diseases within cultivated and wild peanut germplasm, and incorporate resistance into high yielding high oleic peanuts through breeding.
Subobjective 2.A: Identify accessions resistant to Pythium pod rot in the U.S. and ICRISAT mini-core collections, conduct a genome-wide association study (GWAS) to identify Pythium pod rot resistance genes, and develop KASP markers for MAS. Subobjective 2.B: Phenotype near-isogenic introgression lines (NIIL) derived from TXAG-6, an interspecific hybrid derived from Arachis batizocoi, A. cardenasii, A. diogoi, and Florunner, for resistance to early leaf spot and seed colonization by Aspergillus flavus. Subobjective 2.C: Develop and release elite high-oleic, high-yielding, and/or early maturing runner, Virginia, and Spanish peanut cultivars with superior resistance to Sclerotinia blight, southern blight, and pod rot adapted for the Southwest.
Objective 3. Conduct research to determine genetic diversity of pathogens that cause economic damage in peanut.
Subobjective 3.A: Obtain whole genome sequences for two geographically isolated isolates of Thecaphora frezzii and identify markers for population genetic analyses. Subobjective 3.B: Determine if the Thecaphora frezzii isolates from commercial peanut production and surrounding areas are clonal. If they are not clonal, determine if pathogenic diversity is present.
Approach:
Sustainable peanut production in the southwestern United States depends upon the continual improvement and release of new cultivars which increase producers’ profits by lowering input costs. Peanut is highly susceptible to many diseases, and disease control is one of the largest components of production costs. Sclerotinia blight and Pythium pod rot are among the most problematic diseases for southwestern peanut producers, and compared to other diseases, little research is conducted on these pathogens in the U.S. Peanut smut is an emerging disease of concern because it has caused significant losses for the Argentinean peanut industry and potentially may be introduced into the U.S. in future years. To address these needs and concerns, the long-term goal of our research is to develop and release high-yielding, high-oleic peanut cultivars for the Southwest with resistance to a broad suite of diseases and improved agronomic traits. During the next five years, we will identify genetic markers for resistance to Sclerotinia blight, peanut smut, and Pythium pod rot by developing and characterizing recombinant inbred line populations. We will use genetic markers developed by our program and others to develop and release improved cultivars that are adapted to the unique production area of the Southwest. Because cultivated peanut has limited genetic variation, we will screen potential sources of new variation for disease resistance, including the U.S. National Germplasm System (NPGS), International Crops and Research Institute for the Semi-Arid Tropic (ICRISAT) mini-core collections, as well as other wild peanut germplasm collections. We will characterize the diversity of Thecaphora frezzii, the pathogen responsible for peanut smut. Knowledge of the pathogen’s genetic and pathogenic diversity is essential to U.S. efforts in breeding durably resistant cultivars. By developing improved cultivars and markers for resistance to diseases of importance to the region, this project will support Southwest peanut growers and shellers, as well as provide information critical to all peanut production areas in the U.S.
