Ppe.CR.1 DNA test for predicting chilling requirement in peach

Area of Science:

• * Agricultural Science
• * Plant Breeding
• * Molecular Genetics

Background:

• * Chilling requirement (CR) is crucial for peach floral bud break and flowering.
• * Existing research identified CR quantitative trait loci (QTLs), but lacked validated DNA tests for U.S. breeding germplasm.
• * Breeders and growers require accessible DNA tests to predict CR for specific environmental conditions.

Purpose of the Study:

• * To develop and validate a rapid, reliable Kompetitive Allele Specific PCR (KASP) DNA test for predicting peach CR.
• * To integrate CR-associated SNP markers from known QTL regions into a practical diagnostic tool.
• * To provide a cost-effective solution for predicting CR in peach cultivars.

Main Methods:

• * Developed four KASP assays (Ppe.CR.1-1 to -4) using U.S. peach germplasm genotype data and CR-associated SNP markers.
• * Validated assays on 77 peach cultivars and 74 accessions from two F2 populations.
• * Assessed prediction accuracy for CR genotype and phenotype.

Main Results:

• * KASP assays achieved 96% accuracy in determining CR genotype and 74% in predicting phenotype compared to SNP arrays.
• * The Ppe.CR.1 test demonstrated 80% accuracy in predicting CR phenotype in Clemson University breeding material.
• * Specific KASP assays can differentiate between low (<800 hours) and high CR haplotypes, or low, moderate, and high CR alleles.

Conclusions:

• * The developed Ppe.CR.1 KASP DNA test offers a validated, accurate, and low-cost method for predicting peach CR.
• * This tool supports breeders and growers in making informed decisions for peach cultivar selection and development.
• * The test facilitates the prediction of CR in peach material with over 70% accuracy, aiding adaptation to different climates.