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ARS Home » Pacific West Area » Parlier, California » San Joaquin Valley Agricultural Sciences Center » Crop Diseases, Pests and Genetics Research » Research » Research Project #445292

Research Project: Breeding Prunus and Vitis to Improve Disease Resistance, Fruit Quality, and Climate Change Adaptation

Location: Crop Diseases, Pests and Genetics Research

Project Number: 2034-21220-008-000-D
Project Type: In-House Appropriated

Start Date: May 1, 2023
End Date: Apr 30, 2028

Objective 1: Breed superior table grape and natural dried-on-vine raisin varieties with high fruit quality, consumer appeal, disease resistance, and reduced cultural input requirements. Sub-objective 1.A: Develop a pipeline for commercial release of high-quality table grape and natural dried-on-vine raisin selections through field trials. Sub-objective 1.B: Develop high-quality table and natural dried-on-vine raisin grape lines with two or more stacked loci for powdery mildew resistance. Sub-objective 1.C: Develop high-quality table and natural dry-on-vine raisin grape lines with PdR1 and PdR2 locus for durable resistance to PD. Sub-objective 1D: Establish trial of 12 reference cultivars with virus-free material and collect data on anthocyanin and flavonoid compounds. Objective 2: Breed new Prunus selections including self-compatible almond varieties with Nonpareil like kernel characteristics. Sub-objective 2.A: Develop, select, and evaluate new high-yielding self-compatible (SC) almonds. Sub-objective 2.B: Develop, select, and evaluate new glabrous-skinned apricots. Sub-objective 2.C: Test and validate Peach-Nectarine indelG marker in apricots to identify glabrous-skinned apricots.

The long-term goal of the project is to develop superior table grape and natural dried-on-vine raisin varieties that have high quality, consumer appeal, natural disease resistance to fungal and bacterial pathogens and requires reduced cultural input. Each year, crosses will be made among superior selections that has performed well in the field evaluations. Molecular markers will be used to discard disease susceptible lines and to combine different powdery mildew resistance genes for lasting protection. New improved lines will be selected and compared with the existing table grapes for quality and storage after cold treatments and fruit showings will be held during each season. New superior advance lines will be introduced as new cultivars with the table grape and raisin grape industry's approval. We aim to combine Xylella fastidiosa (Xf) resistance from Vitis arizonica into high-quality hybrids of both table and raisin grape cultivars. Xf is a bacterial disease that threatens grape production. Studies will be carried out to characterize the profile of anthocyanin (free and bound) and flavonoid compounds of 12 varieties under two different climate conditions. Same set of plants will be grown in the Parlier, and Coachella valley that is significantly warmer. Both anthocyanins and flavonoids are negatively impacted by high daily temperatures. This experiment will allow to study the impact of temperature on the stability of these compounds and identify varieties that perform better in hot climates to facilitate future breeding efforts to mitigate the impact of climate change. To create new self-compatible (SC) almonds with high yields and Nonpareil-like kernels, crosses will be made each year between SC lines. Seedlings will be genotyped with markers that target SC locus and only the lines with SC will be kept. Flowers will be bagged and only lines that would not require insects for pollinations will be selected. Phenological data will be collected annually and compared to the standard cultivars ‘Nonpareil’ and ‘Padre.’ Only lines that have most desirable combination of nut and tree characteristics will be selected and trialed further. New apricot varieties will be developed by crossing different types of smooth-skinned apricots. DNA-based marker assay will be developed to identify smooth skin apricots at earlier seedling stage to distinguish glabrous apricots from fuzzy apricots. Selected lines will be evaluated for their fruit quality and productivity.