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ARS Home » Southeast Area » Tifton, Georgia » Crop Genetics and Breeding Research » Research » Publications at this Location » Publication #309937

Title: Considerations for marker-assisted selection in peanut

item BUROW, MARK - Texas A&M Agrilife
item CHOPRA, RATAN - Texas Tech University
item SIMPSON, CHARLES - Texas A&M Agrilife
item BERTIOLI, DAVID - University Of Brasilia
item Holbrook, Carl - Corley
item STALKER, H. THOMAS - North Carolina State University
item VARSHNEY, R - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/1/2014
Publication Date: N/A
Citation: N/A

Interpretive Summary: not required

Technical Abstract: Marker-assisted selection (MAS) offers considerable promise but requires careful planning. Among the first DNA markers used for peanut improvement were wild species-derived alleles for nematode resistance, now being combined with the high-oleic trait. These are screened as qualitative traits. These efforts have contributed to release of nematode-resistant cultivars, but are simple compared to future needs. Most traits are quantitative, controlled by multiple genes. Some QTLs (quantitative trait loci) have been developed for resistance to leaf spots and rust, tolerance to drought stress, and agronomic and kernel traits. MAS will require pyramiding QTLs, and can combine genes with different functions, reduce linkage drag, and develop more-durable pest resistance. Populations for marker work are typically F2's, backcrosses, and RILs, including 16 CAPS RIL populations developed for GWAS (genome-wide association studies). Markers need to be validated when used in new genetic backgrounds. Use of wild species, plant introductions, and (mini)core accessions can provide additional and stronger QTLs. Sufficiently-large populations are needed for combining QTLs. Linkages among favorable and unfavorable alleles need to be broken. Recurrent selection can break up conserved linkage blocks; MAGIC populations can for multiple parents. Scoring in the F2, F3, or backcross generations permits earlier selection of quantitative traits, and has the potential to cut cultivar development time substantially, but will require larger populations earlier. Although genotyping costs are declining, breeding programs will face choices of resource allocation among traits, markers, crosses, and field testing. Finally, potential cultivars will need to be field tested to verify phenotypes.