|Walker, M. Andrew|
Submitted to: American Journal of Enology and Viticulture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/30/2009
Publication Date: 6/15/2009
Citation: Riaz, S., Tenscher, A.C., Graziani, R., Krivanek, A.F., Ramming, D.W., Walker, M. 2009. Using Marker-Assisted Selection to Breed Pierce’s Disease-Resistant Grapes. American Journal of Enology and Viticulture. 60(2):199-207. Interpretive Summary: Pierce’s disease (PD), caused by the bacterium Xylella fastidiosa, is wide spread in the Southern United States. This disease has caused periodic destruction of grape production areas since the early 1900’s. With the recent introduction of the glassy-winged sharpshooter into California, epidemics of PD have occurred. A breeding program to develop wine, table and raisin grape cultivars with resistance to PD was started in 2000. Resistance from Vitis arizonica, b43-17, has been incorporated into F1 and backcross generations 1 and 2. Molecular markers were developed to select PD resistant plants from a total of 4,321 seedlings from 83 different crosses. The markers linked to resistance were unique in size and were not shared by susceptible V. vinifera selections. Based on the presence of markers, 1,683 seedlings from wine, table, and raisin grape backgrounds were selected. Distinctiveness of these resistant markers allows them to be used for Marker Assisted Selection to optimize the breeding of PD-resistant grape cultivars.
Technical Abstract: Pierce’s disease (PD), caused by the bacterium Xylella fastidiosa, is an important disease of grapevines in California, across the southern United States, and into South America. In regions where disease pressure is high, cultivation of Vitis vinifera cultivars is difficult or impossible. This study reports on introgression of PD resistance into elite wine, table, and raisin grape genetic backgrounds and on reliability of PCR-based marker-assisted selection (MAS) to accelerate breeding of PD-resistant grapes. This work documents introgression of PD resistance from a homozygous resistant form of V. arizonica, b43-17. A total of 4,321 seedlings from 83 different crosses of resistant selections and high-quality susceptible V. vinifera cultivars (F1, first and second generation modified backcrosses mBC1, mBC2) were screened with two to three flanking microsatellite markers (VVIP26 and ctg1026876, VMC2a5) in early spring of 2006 and 2007. Alleles linked to resistance were unique in size and were not shared by susceptible V. vinifera selections. Based on presence of unique resistant alleles, 1,683 seedlings from wine, table, and raisin grape background were selected. Distinctiveness of these resistant alleles allows use of MAS to optimize breeding of PD-resistant grape cultivars.