Location: Crop Diseases, Pests and Genetics Research
Project Number: 2034-21220-007-000-D
Project Type: In-House Appropriated
Start Date: May 1, 2018
End Date: Apr 30, 2023
Objective:
The long-term goal of this project is development and introduction of new, high-quality and disease resistant cultivars of Prunus (almond and apricot) and Vitis (table grapes and raisins) that will sustain American agriculture and supply high quality, nutritious fruits and nuts to U.S. consumers and international markets. Further, the project will strive to identify molecular markers linked sufficiently close to fruit quality traits of interest such that marker-assisted selection will be possible in future breeding efforts. Specifically, during the next five years we will focus on the following objectives:
Objective 1: Enhance breeding efficiency for table grape fruit quality, and other priority traits, by identifying associated molecular markers, and through trials, to determine commercial acceptability of advanced table grape selections.
Sub-objective 1A: Develop segregating populations and map fruit quality traits related to flowering time, rachis architecture, and berry size.
Sub-objective 1B: Through trials, determine commercial acceptability of advanced table grape selections.
Sub-objective 1C: Identify sources of resistance and develop molecular markers associated with resistance to Botrytis cinerea.
Objective 2: Develop durable resistances to powdery mildew and Pierce’s disease in table grapes and natural dry-on-vine raisins.
Sub-objective 2A: Develop durable resistance to powdery mildew in table grapes and natural dry-on-vine raisins.
Sub-objective 2B: Identify sources of durable resistance to Pierce’s disease and determine the relative susceptibility of existing commercial cultivars.
Sub-objective 2C: Develop table grape and natural dry-on vine raisin cultivars with durable resistance to Pierce’s disease.
Objective 3: Develop, select, and evaluate new, high quality scions of Prunus, e.g., high yielding self-compatible almond and glabrous-skinned apricot.
Sub-objective 3A: Develop, select, and evaluate new high-yielding self-compatible almonds.
Sub-objective 3B: Develop, select, and evaluate new glabrous-skinned apricots.
Approach:
Classical breeding has been used to create segregating populations in Prunus and Vitis where the expression of quantitative traits has been concentrated and newly available characters have been transferred into adapted germplasm. New segregating populations will be created in Vitis to develop molecular markers for fruit quality traits, rachis architecture, resistance to Botrytis, flowering time and berry size. Advanced table grape selections will be compared for production timing and fruit quality after cold storage with existing table grape cultivars through public fruit showings held during each ripening season. Commercially acceptable advanced table grape selections will be introduced as new cultivars through consensus evaluation with the table grape industry.
New powdery mildew resistance sources will be evaluated in established segregating populations, and resistant accessions will be backcrossed with high quality table grapes and natural dry on the vine raisins as molecular markers are being developed. These new resistance sources will be used along with other mapped PM resistance sources in hybridizations designed to stack the resistances for durability. Empirical screening of Vitis germplasm for reaction to Xylella fastidiosa will continue, and existing commercial table grape cultivars will be evaluated for their relative susceptibility to Pierce’s disease. Crosses will be conducted to stack Xf resistances from Vitis arizonica and southeast U.S. Vitis germplasm into hybrids with high product quality. Promising high quality accessions with will be evaluated for survival and productivity in regions with high Pierce’s disease pressure.
In Prunus, hybridizations will be performed to identify and select new high-yielding self-compatible almonds that are California-adapted and have Nonpareil-like kernel characteristics. Apricot populations will be developed through hybridization among glabrous-skinned accessions, and new glabrous apricots will be evaluated for fruit quality and productivity. Newly-available glabrous-skinned apricot accessions from Kyrgyzstan will be propagated when available from plant protective quarantine and used in hybridizations to assist in the glabrous-skinned apricot breeding effort.
