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ARS Home » Southeast Area » Byron, Georgia » Fruit and Tree Nut Research » Research » Publications at this Location » Publication #414347
Research Project: Healthy, Sustainable Pecan Nut Production

Location: Fruit and Tree Nut Research

Title: High-density Linkage Mapping and Identification of Quantitative Trait Loci Associated with Leaf Scab Resistance in Pecan (Carya illinoinensis)

Author
item BHATTARAI, GAURAB - ARS Postdoctoral Research Associate
item CAO, SHANSHAN - University Of Georgia
item BENTLEY, NOLAN - University Of Texas
item KLEIN, PATRICIA - Texas A&M University
item Bock, Clive
item Pisani, Cristina
item CONNER, PATRICK - University Of Georgia

Submitted to: Symposium Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 5/5/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Genetic maps are essential tools for gene positional cloning and marker-assisted breeding. A pecan mapping population of 119 F1 trees was derived from a cross of the widely planted cultivars Pawnee and Elliott. Whereas ‘Pawnee’ is susceptible, ‘Elliott’ has long-standing resistance to pecan scab caused by the fungal pathogen Venturia effusa. Molecular markers were developed using genotyping-by-sequencing (GBS), and linkage maps were constructed for each parent following the two-way pseudo-test-cross strategy used for cross-pollinated species. The ‘Pawnee’ and ‘Elliot’ maps contain 1,347 and 1,050 single nucleotide polymorphism (SNP) markers spanning a genetic distance of 4,493.0 and 3,758.4 cM, respectively. A high level of synteny between genetic and physical distances of the markers in both parental maps was achieved. Scab resistance was evaluated through controlled inoculations in the greenhouse using two scab isolates, and a significant QTL for scab resistance was identified on chromosome 5 in ‘Elliott’. Candidate gene searches within the 2-LOD interval of the scab-resistant QTL identified a number of disease resistance-related genes including genes encoding wall-associated receptor kinases (WAKs), cytochrome P450s, LRR receptor-like serine/threonine-protein kinases, a pectinesterase inhibitor, a cellulose synthase, a flavonol synthase, a 4-coumarate--CoA ligase, a caffeic acid 3-O-methyltransferase, and a MYB domain transcription factor.