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ARS Home » Northeast Area » Kearneysville, West Virginia » Appalachian Fruit Research Laboratory » Innovative Fruit Production, Improvement, and Protection » Research » Research Project #434486

Research Project: Improving Stress and Disease Resistance in Apple Germplasm

Location: Innovative Fruit Production, Improvement, and Protection

Project Number: 8080-21000-026-00-D
Project Type: In-House Appropriated

Start Date: Mar 26, 2018
End Date: Mar 25, 2023

Objective:
Objective 1: Develop elite breeding parents for apple containing both disease resistance alleles to blue mold, apple scab, and fire blight, and desirable fruit quality alleles using rapid cycle breeding technology. [NP301, C1, PS1B] Objective 2: Utilize Malus sieversii (an apple progenitor species) and a forward overexpressing system (FOX-hunting) to identify and functionally analyze apple genes conferring disease and environmental stress resistance. [NP301, C3, PS3A] Objective 3: Utilize CRISPR technology to improve disease resistance or environmental stress tolerance in 'Royal Gala'. [NP301, C1, PS1B]

Approach:
Environmental stress and outbreaks of disease can severely reduce apple fruit production. New cultivars with improved stress and disease resistance will be needed in order for the U.S. apple industry to remain competitive. Rapid cycle breeding will be used to combine multiple disease resistance alleles for fire blight, apple scab and blue mold resistance within genetic backgrounds that are suitable for use in apple breeding programs. DNA-informed breeding methods, rather than conventional phenotyping methods, will be used to predict individuals with multiple sources of disease resistance and fruit quality traits. The wild apple species, Malus sieversii, is considered to represent a reservoir of disease and stress resistance genes, as well as a source of novel, quality traits (flavour, texture, etc.). A Full-length cDNA Over-eXpressing (FOX) Gene Hunting system will be used to conduct high-throughput screening of genes in Malus sieversii – PI613981 (disease and drought tolerant elite genotype) that are associated with freezing, drought, and salt tolerance. Once vetted, the identified genes will be used to produce apple genotypes of ‘Royal Gala’ with improved stress tolerance. Lastly, several potential genes regulating time of bud break will be characterized in transgenic and non-transgenic apple lines to confirm their role in the regulation of bud break. Key regulatory motifs in the promoters of these genes will be modified using CRISPR/Cas9 technology to produce genotypes with delayed bud break in order to adapt apple genotypes to erratic spring weather patterns.