Skip to main content
ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #330424
Title: Identification of rare recombinants leads to tightly linked markers for nematode resistance in peanut

Author
item CHU, Y - University Of Georgia
item GILL, R - University Of Georgia
item CLEVENGER, J - University Of Georgia
item Timper, Patricia - Patty
item Holbrook, Carl - Corley
item OZIAS-AKINS, P - University Of Georgia

Submitted to: Peanut Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/2/2016
Publication Date: 8/31/2016
Citation: Chu, Y., Gill, R., Clevenger, J., Timper, P., Holbrook Jr, C.C., Ozias-Akins, P. 2016. Identification of rare recombinants leads to tightly linked markers for nematode resistance in peanut. Peanut Science. 43(2):88-93.

Interpretive Summary: Strong host resistance to root-knot nematode (RKN) bred into to cultivated peanut from a wild diploid species was previously shown to be located on a large chromosomal region of linkage group A09. Little to no recombination in this chromosome region has hindered fine mapping of the resistance genes. In order to further delineate the region containing alien genes from the wild species, additional genetic markers were added to the linkage group A09 using an inbred line population developed from the cross Gregory x Tifguard in which Gregory is the susceptible parent and Tifguard is the resistant parent harboring the alien genes from the wild species. Some plant lines showed a rare recombination in which the alien region of the chromosome was broken apart with some plants containing only part of the alien region. These rare plant lines were evaluated for nematode resistance and it was demonstrated that one portion of the region from the wild species confers moderate resistance while a smaller, distal portion confers strong resistance to RKN. Molecular markers associated with the alien region conferring strong resistance can be deployed in peanut breeding programs to improve selection for RKN resistance.

Technical Abstract: Strong host resistance to root-knot nematode (RKN; Meloidogyne arenaria) introgressed from a wild diploid species to cultivated peanut was previously shown to be located on a large chromosomal region of linkage group A09. Little to no recombination in mapping populations has hindered fine mapping of the resistance genes. In order to further delineate the introgressed region, additional polymorphic markers were added to the linkage group A09 using a recombinant inbred line population developed from Gregory x Tifguard in which Gregory is the susceptible parent and Tifguard is the resistant parent harboring the alien introgression. Map distance within the introgressed region based on this population increased to 8 cM compared with zero recombination in an earlier generation. Lines with rare recombination within this introgressed region were phenotyped and it was demonstrated that one portion of the introgressed region confers moderate resistance while a smaller, distal portion confers strong resistance to RKN. Molecular markers associated with the introgressed region conferring strong resistance can be deployed in peanut breeding programs to improve selection for RKN resistance.