DEVELOPMENT OF PEANUT LINES WITH SUPERIOR PEST RESISTANCE USING WILD SPECIES AND MARKER-ASSISTED BREEDING

Peanut is an expensive, high agrochemical input crop. This project aims to build on the previous achievements to make a major impact on peanut cultivation in the U.S. by reducing farmers' agrochemicals costs for control of pests and diseases and increase production. We propose to accomplish this via the introgression of high value chromosomal segments from wild species that confer strong pest and disease resistances into peanut using crossing schemes aided by genome information and genotyping. We also aim to create a publicly available strategic resource to facilitate the introduction of new wild genes into peanut breeding programs much beyond the duration of this project.There is one main goal - peanut improvement using wild species - divided in three objectives that we envisage will bring benefits to the U.S. agriculture in the short-, medium-, and long-term. All milestones can be accomplished within the time frame of this project. At the end of the project, we expect to have advanced lines at the point to be taken to multi trial experiments for cultivar release; advanced lines in various stages of development, with defined wild-derived segments that confer resistance to at least three of the main peanut pests of the USA; and a structured collection of wild-derived allotetraploids/neopolyploids available to the peanut community through the NPGS.The project has one main goal, divided in three objectives (short-, medium, and long-term), with different milestones that can be accomplished within the time frame of this project.Objective 1 - long-term - Laying a new genetic foundation for breeding - Here we want to make wild alleles available in the tetraploid form, so they can be utilized in breeding programs. We will build a Structured Arachis Neotetraploid Core Collection. This will involve Primary diploid crosses, confirmation of F1 diploid hybrids, genome duplication of F1 diploid hybrids, genotyping of newly formed allotetraploids, evaluation of newly formed allotetraploids for disease resistance, seed multiplication and germplasm registration/deposit in the USDA National Plant Germplasm SystemObjective 2 - Medium term - Moving wild alleles along the pipeline. - Map and introgress resistance to pests and diseases from chromosomal wild segments into peanut elite lines. Here we will move move wild alleles into peanut lines by crossing, selecting, mapping. The main activities are: Crosses neotetraploids x peanut; Mapping of ELS and Rust resistance in BatSten BC3F2 and MagSten3 BC3F3 material; Mapping of TSWV resistance in BatSten BC3 material; Mapping of White Mold resistance in a ValSten x cultivated peanut F2 population; Development of marker for disease resistances mapped in activities ii), iii) and iv).Objective 3 - Short term - incorporate and combine late, early leaf spot and root-knot nematode resistance loci in advanced germplasm and cultivars. Here we use advanced lines to reach the end goal - create peanut lines with multiple resistances. The main activities are: Mapping of Early Leaf Spot resistance loci from A. cardenasii in Bailey; Advance new sources of leaf spot resistance from A. cardenasii, for release of new peanut germplasm and cultivars; Advance new sources of nematode resistance from A. stenosperma, for release of new peanut germplasm and cultivars; Combining ELS, LLS and RKN-(A cardenasii) and RKN-(A stenosperma) resistance loci