Skip to main content
ARS Home » Pacific West Area » Parlier, California » San Joaquin Valley Agricultural Sciences Center » Crop Diseases, Pests and Genetics Research » Research » Publications at this Location » Publication #400152
Research Project: Breeding Prunus and Vitis Scions for Improved Fruit Quality and Durable Pest Resistance

Location: Crop Diseases, Pests and Genetics Research

Title: Identification of Pierce’s disease resistance in a V. girdiana hybrid from Baja California Sur, Mexico

Author
item Riaz, Summaira
item Tenscher, Alan
item WALKER, MICHEAL - University Of California, Davis

Submitted to: Journal of Plant Science and Molecular Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/27/2025
Publication Date: 1/6/2026
Citation: Riaz, S., Tenscher, A.C., Walker, M.A. 2026. Identification of Pierce’s disease resistance in a V. girdiana hybrid from Baja California Sur, Mexico. Journal of Plant Science and Molecular Breeding. 44. Article 33. https://doi.org/10.1007/s11105-025-01669-0.
DOI: https://doi.org/10.1007/s11105-025-01669-0

Interpretive Summary: Natural Pierce's disease resistance is widespread in wild grape species in Mexico and Southwest USA. This study report Pierce’s disease (PD) resistance characterization in the accession b42-26 that was collected from Baja California Sur, Mexico. The genetic analyses identified large effect quantitative trait locus (QTL) on chromosome 8 that was designated as Pierce’s disease Resistance 2 (PdR2). The identification of new locus is of great importance for PD resistance breeding. It provides opportunity for the grape breeder to combine PD resistance from multiple backgrounds into a single line for durable field resistance.

Technical Abstract: In this study, we report on the genetic mapping and quantitative trait locus (QTL) analyses for the Pierce’s disease (PD) resistance in the accession b42-26; a form of Vitis girdiana collected from Baja California Sur, Mexico. Simple sequence repeat (SSR) markers were used to develop the genetic map. Results indicated that b42-26 is highly homozygous with only 25% polymorphic markers. None of the tested markers were polymorphic for chromosome 19. Major regions of segregation distortion were identified on chromosome 1, 4, 6, and 7 and all markers on chromosome 10, 11, 12, and 18. The quantitative trait locus analyses identified four QTLs on chromosome 8, 10, 14 and 17 (one each) that explained 16.3% of the phenotypic variation. Large effect quantitive trait locus (QTL) on chromosome 8 was designated as Pierce’s disease resistance 2 (PdR2) and was also tested in backcross breeding populations.