Assessment of a Muscadine Grape (Vitis rotundifolia) Mapping Population for Tolerance to Pierce’s Disease Pathogen Xylella fastidiosa and Resistance to Black Rot Disease Pathogen Guignardia bidwellii

<p>Pierce’s disease (PD) and black rot disease cause severe economic losses for grape production under humid and warm conditions. Identifying resistance genes is crucial for controlling these disease by developing resistant cultivars. Muscadine grape (<em>Vitis rotundifolia</em>) cultivar ‘Pam’ has been identified to possess a high level of resistance to diseases. To elucidate the genetic basis of the resistance to the causal pathogens <em>Xylella fastidiosa</em> and <em>Guignardia bidwellii</em> in this cultivar, parents and 141 F1 individuals developed from open pollinated ‘Pam’ were evaluated for two seasons under natural disease pressure. The mapping population was genotyped using genotyping-by-sequencing (GBS) and a genome-wide association (GWAS) approach, based on 80,507 single-nucleotide polymorphism (SNP) markers. Results showed that only 10 genotypes were positive for PD during both seasons, and the average disease severity in the mapping population for black rot ranged from 0.09% to 14.10%. The GWAS analysis, using genotypic data and phenotyping data for black rot, identified major quantitative trait loci (QTL) on chromosome 16. The QTL for resistance was consistent across both years, and one significant SNP marker was consistently detected. Among the genes located in the major QTL interval, nine genes had annotation results, and the most significant candidate gene was found to encode a functional protein for bark storage protein A. The multiple significant markers identified in this study could be utilized to develop markers to assist in marker-assisted breeding programs.</p>

Name thesis:degree_name

Master of Science (MS)

Level thesis:degree_level

Masters Thesis

Year dc:date.available

2025

Author dc:creator

• Tennakoon, Anushka

Contributors dc:contributor

• Dr. Micheal Davis
• Dr. Dmitri Mavrodi
• Dr. Ebrahiem Babiker

• Guignardia bidwellii
• Vitis rotundifolia
• black rot
• GBS
• grapes
• mapping
• Plant Breeding and Genetics

Repository record dc:identifier

https://aquila.usm.edu/masters_theses/1146

OAI identifier oai:identifier

oai:aquila.usm.edu:masters_theses-2222