Location: Crop Genetics and Breeding Research2018 Annual Report
Objective 1: Identify and characterize genes/Quantitative Trait Locus (QTLs) controlling resistance to major diseases (leaf spot, white mold, rhizoctonia limb rot, and nematodes) and drought stress, and use the information in marker-assisted breeding to develop improved high oleic (oleic/linoleic fatty acid ratio) peanut cultivars or germplasm with tolerance to biotic and abiotic stresses. Sub-objective 1.A.: Conduct phenotypic evaluations of recombinant inbred line (RIL) populations to aid in the identification and characterization of genes/QTLs controlling resistance/tolerance to biotic and abiotic stresses. Sub-objective 1.B.: Develop improved high oleic peanut cultivars or germplasm with resistance to nematodes and improved resistance to leaf spot. Sub-objective 1.C.: Develop high oleic peanut germplasm with improved drought tolerance and reduced preharvest aflatoxin contamination (PAC).
1.A. Sixteen structured recombinant inbred line (RIL) populations were developed using parents that were selected to maximize genetic diversity while meeting practical breeding objectives. In-depth phenotyping and genotyping of the populations will be conducted to identify genetic markers that can be used in peanut cultivar development. 1.B. Breeding populations will be developed by hybridizing cultivars with high oleic acid with high yielding breeding lines with resistance to the peanut root-knot nematode and/or resistance to leaf spot. Marker assisted selection will be utilized to select early generation progeny that are homozygous for the desired characteristics (high oleic, nematode resistance, and/or leaf spot resistance). Selections in later generations will focus on field resistance to tomato spotted wilt virus, high yield, and other agronomic characteristics. 1.C. Breeding populations will be developed by hybridizing high-yielding, high-oleic cultivars with sources of resistance to preharvest aflatoxin contamination and sources of resistance to drought. These populations will be evaluated under field conditions with drought and heat stress imposed by covering the entire test area with a mobile greenhouse. Aflatoxin contamination of the subsequent yield will be determined using the immunoaffinity column fluorometer method. Progeny will be selected based on relatively low aflatoxin and/or relatively high pod yields.
Since the beginning of this new project in March 2018, we planted over 25 acres of field plot research. This included numerous replicated studies, and breeding plots for selection and generation advance. The goal for all this research is the development of high-yielding, high-oleic peanut cultivars or germplasm with tolerance to biotic and abiotic stresses.