Location: Crop Diseases, Pests and Genetics Research
Project Number: 2034-22000-014-013-R
Project Type: Reimbursable Cooperative Agreement
Start Date: Oct 1, 2021
End Date: Sep 30, 2025
Objective:
The overall objective of this effort is to conduct a pilot research project on citrus breeding at the San Joaquin Valley Agricultural Sciences Center in Parlier, CA to develop and evaluate high-quality, superior citrus selections for use in citrus production regions throughout California. Research proposed here can be accomplished in the short- and medium-term within five years. Short-term objectives (years 1 to 3) will involve establishment of available parental selections, advanced rootstock selections (able to be established by seed), advanced scion selections already present in California, and commercial citrus cultivars in the field. Medium-term objectives (years 3 to 5) will involve the establishment of advanced scion selections (following four years to clear phytosanitary regulations), and evaluation of rootstock selections for effect on horticultural traits including yield, vigor, tree size, abiotic stress tolerance, scion compatibility, fruit maturity period, and fruit characteristics including size, peel, flavor, color, and seedlessness. In addition to orchard establishment, research involving greenhouse phenotyping for accelerating citrus breeding on water quality issues and disease will be conducted. Phenotyping will utilize and adapt existing protocols to assess the ability to screen citrus materials for abiotic (water quality and quantity), and biotic (CTV, nematodes, and fungal pathogens) stress tolerance.
Approach:
This research proposal establishes citrus crop breeding capacity at the San Joaquin Valley Agricultural Sciences Center. Citrus materials to be evaluated include fresh fruit selections with navel oranges as priority but should also include other varieties including mandarins and grapefruit. Evaluations support long-term breeding objectives that prioritize fruit quality and yield, followed by tree health, and rootstock/scion compatibility. Evaluations will initially focus on materials currently being evaluated at Stage III (In-House Trials) and Stage IV (Regional Trials) levels with subsequent development of evaluation protocols for material selection at Stage I and Stage II. For reference:
• Stage I: Parental identification and crosses. Researchers use multiple techniques and tools to aid in the identification and selection of parents for crosses, and mate them by whatever technique they deem appropriate for the breeding or genetic objectives.
• Stage II: Progeny selection. Researchers make selections (typically as the “Breeder of Record”), which are often propagated to create additional material for later stages.
• Stage III: In-House trials. Selections, or candidate lines, are evaluated in controlled research sites to observe standardized traits (phenotyping) and compared to industry standards as well as other candidate lines.
• Stage IV Regional Trials: Evaluations are typically conducted under commercial grower conditions to determine commercial potential.
