Location: Nat'l Clonal Germplasm Rep - Tree Fruit & Nut Crops & Grapes
2022 Annual Report
Objectives
The long-term objective of this project is to preserve the genetic diversity in the collections of the 14 Mediterranean crops for current and future generations. Specifically, during the next five years we will focus on the following objectives.
Objective 1: Efficiently and effectively acquire priority Mediterranean climate-adapted grape, tree fruit, tree nut, and other specialty crop genetic resources; maintain their safety, genetic integrity, health and viability; and distribute them and associated information worldwide.
Objective 2: Develop more effective genetic resource maintenance, evaluation, and
characterization methods and apply them to priority Mediterranean climate-adapted grape, tree fruit, tree nut, and other specialty crop genetic resources. Record and disseminate evaluation and characterization data via GRIN-Global and other data sources.
Objective 3: With other NPGS genebanks and Crop Germplasm Committees, develop, update, document, and implement best management practices and Crop Vulnerability Statements for Mediterranean climate-adapted grape, tree fruit, tree nut, and other specialty crop genetic resource and information management.
Basis for the objectives: The first two objectives describe the four basic tenets of the mission of the National Clonal Germplasm Repository Davis (NCGR); acquisition, maintenance, characterization and distribution of high quality, healthy, viable, true-to-type genetic resources and the associated evaluation and characterization information in GRIN-Global to the domestic and international scientific and educational communities. The third objective focuses on developing, implementing, and documenting best management practices for the collections and keeping the Crop Vulnerability Statements up-to-date.
Acquisition has focused on crop wild relatives (CWRs) to fill important gaps and much of this germplasm is under quarantine and therefore in the pipeline to the Repository. Maintenance is best accomplished with young, vigorous plants and therefore the Repository is in the middle of a repropagation cycle for the collections. Distribution of germplasm to national and international researchers, breeders, and nurseries is primarily, but not limited to dormant cuttings or scionwood.
Phenotypic evaluation and genetic characterization of the collections focus on
understanding genetic diversity and increasing the visibility and value of the germplasm. Stakeholders are interested in phenotypic data on traits with breeding value. We use Bioversity International descriptors for germplasm evaluation and upload these data to GRIN-Global. Genetic markers discovered at the Repository and by collaborators can help clarify accession identity and assess genetic diversity, structure, and differentiation, and when combined with phenotypes will enhance the value and promote utilization of the germplasm.
Approach
Objective 1
Research Goal 1: Implement best management strategies for the acquisition, maintenance, and distribution of the genetic resources of the NCGR.
Approach: This objective describes three of the four basic tenets of the mission of the National Clonal Germplasm Repository for tree fruits, nut crops and grapes (NCGR) of acquisition, maintenance of the germplasm, and distribution of high quality, healthy, viable, trueto-type genetic resources to the domestic and international scientific and educational communities. The fourth tenet is evaluation and characterization covered in Objective 2. This and other objectives are accomplished by 10 full-time staff, as well as 2-5 part-time student workers.
Objective 2
Research Goal 2: To have better maintained and more thoroughly evaluated and characterized collections and to make the resulting descriptor information more complete and up-to-date in GRIN-Global.
Approach: This objective describes making collection maintenance more effective and is well aligned with the maintenance portion of Objective 1. Evaluation and characterization of the collections increase the visibility and usefulness of this valuable germplasm to the stakeholder community. Phenotypic descriptors have great utilization and help guide breeders and others who must decide which accessions will help advance their program. Therefore, phenotyping is a focus of the NCGR. Genotypic descriptors, such as SSR and SNP markers are also developed for the collections and are useful to the scientific community and for combining with rich phenotypic data to discover QTLs.
Objective 3
Research Goal 3: Regularly document best management practices and update Crop
Vulnerability Statements every 3-4 years.
Approach: This objective describes developing updated and documented best management practices for collection management and evaluation. It also is important to have up-to-date crop vulnerability statements to facilitate communication with stakeholders, identify gaps in the collection, and identify management improvements potentially increasing yield and quality of regenerated propagules. In addition, Crop Vulnerability Statements are used by Office of National Programs when communicating with leadership and lawmakers.
Progress Report
In support of Objective 1, research continued the implementation of best management strategies for the acquisition, maintenance, and distribution of genetic resources tree fruits, nut crops, and grapes in Davis, California (the Repository). Field space continues to be limited and the University of California, Davis, which leases land for the research, has not been able to allot more land to the permanent field collections. Although this project is not seeking to greatly expand the collections due to limited field space, previously collected germplasm of Prunus (mainly apricots and plums) and other crops continue to slowly clear USDA Animal and Plant Health Inspection Service (APHIS) quarantine in Beltsville, Maryland. Therefore, there is a backlog of new acquisitions arriving yearly, expanding the collections and addressing part of Objective 1. During FY 2022, the Repository received eight new accession seedling families collected in Albania, along with 11 clonal accessions received as grafted trees or budwood. Ten historical almond cultivars came to the repository through Burchell’s Nursery, and one high altitude almond was collected from Idaho.
In late summer 2021, one of the wells supplying irrigation to the field began to fail. Staff worked quickly to employ emergency watering strategies, including tank-watering, connecting to water from neighboring farms, and eventually establishing an alternate short-term water source from a surface water canal. A test well was dug to collect data for design of a new well, and procurement of this critical service is underway.
Due to uncertainty in the water supply this year, new field plantings were limited. In the close-planted orchard (where trees are being grown until orchard land is available), 58 almonds and 137 persimmon trees were planted. In the permanent Peach block, 28 trees (18 new accessions) were planted. In the kiwifruit block, 15 accessions were planted during the fall of 2021. In addition, 33 accessions from the kiwifruit collection were re-propagated at the nursery and will be ready to be planted in the fall of 2022. During FY 2022, the last 18 fig accessions from the old fig block were re-propagated, so that the old block can be removed to create more space for new plantings. In addition, 28 fig accessions were re-propagated from old plants that only exist at the nursery in pots due to limited field space. A source for fig accessions that have been lost over the years has been identified in San Diego, California. In the grape collection, cuttings for 336 accessions were collected for grafting and 315 accessions had at least one successful graft. In addition, 244 accessions were propagated on their own roots in pots as backups. This material will be used to replace dead or weak vines in the spring of 2023.
Tree and vine maintenance in the field and nursery continue to be the major emphasis and are year-round activities. The walnut and pistachio collections were mechanically pruned. Weedy perennial seedlings were removed from the majority of the grape collection. This will double the speed of the springtime pruning in the future, which has become even more important as contracting a pruning crew has become more difficult. Manual pruning of trees and removal of weedy trees and suckers was performed for the collections as needed including Prunus, kiwifruit, and others. Sprays were employed for insect pests and diseases caused by microbes and nutrient deficiencies. Weed control (i.e., herbicides) and removal activities continued to require significant effort from the staff.
Distribution of all forms of genetic materials including dormant and green cuttings/budwood, pollen, and leaves continued. From August 1, 2021, to July 31, 2022, staff shipped 220 orders (Domestic: 214 total-15 Federal, 53 State, 55 Commercial, seven Non-profit, 84 individuals. International: six total). The 220 orders consisted of 3,153 inventories that were shipped during that time period. Two thousand four hundred fifty-four (2,454) inventories were collected as bud sticks/cutting with a total of 12,249 sticks. Two inventories were collected as fruit with a total of 94 fruit. Three hundred forty-two (342) inventories were collected for packets of leaves. Three inventories were shipped as plants with a total of 16 plants. Seventy-five (75) inventories were collected as vials of pollen. Two hundred seventy-seven (277) inventories were collected as packets of seed. Some international requests could not be sent because of stringent phytosanitary requirements for shipping to the European Union, specifically for those crops that are hosts of Xylella fastidiosa. In addition to fulfilling requests from genebank customers, pollen and cuttings were collected and shipped to ARS researchers in Fort Collins, Colorado, for cryopreservation. From August 1, 2021, to July 31, 2022, staff sent three shipments of Prunus pollen vials (12 inventories), four shipments of walnut pollen (27 inventories) and three shipments of grape green cuttings (30 inventories with a total of 260 cuttings). Backing up the collections through approaches such as cryopreservation is necessary where maintenance fails, or plants do not thrive.
In support of Objective 2, ARS researchers in Davis, California, continued the evaluation of the collections and posting of those results in the Germplasm Resources Information Network (GRIN) Global database so that stakeholders can better understand and use the collections in their research. Knowledge of the amount and patterns of distribution of genetic diversity within and among species' gene pools is of considerable value for effective conservation, enrichment, management, and utilization of genetic resources. Work continued on updating the GRIN-Global database. From August 1, 2021, to July 31, 2022, staff created 83 new accession records and modified 479, and created 1,059 new inventory records and modified 10,161. Additional information about germplasm was added to GRIN-Global in the form of images (99 new and 4,232 modified), source records (90 new and 474 modified), and other observations (11,793 new: 1,115 records for Almond, 3,898 records for Apricot, 12 records for sweet cherry, 6,616 records for Peach and 152 records for Plum).
In support of Objective 3, ARS researchers in Davis, California continued developing updated and documented best management practices for collection management and evaluation in both the field (orchards and vineyards) and nursery operations. A pest control advisor is now routinely consulted about pest and other management issues in the orchards and vineyards. This has helped address a zinc deficiency issue in some of the collections. A new push-behind trimmer mower was employed to mechanically remove weeds both at Wolfskill and the nursery grounds. New specialized equipment was procured for the removal of ground squirrels, which have been an established pest problem in older orchard areas. Over two tons of sand was pumped into the underground dens, removing habitat and stabilizing the soil. In the nursery, routine evaluation of greenhouse/screenhouse management practices such as propagation techniques continued to be performed. Standard operating procedures for the repository operations continued to be updated as warranted.
Accomplishments
1. Crop germplasm distribution. ARS researchers in Davis, California, distributed genetic resources, free of charge, to cooperators worldwide, especially geneticists and breeders who develop new cultivars to address the needs of growers and consumers. Most germplasm requests were shipped in late winter/early spring as three to five cuttings per accession. Leaves, pollen, and fruit were also sent as requested. ARS scientists and staff in Davis, California, shipped 3,153 items to 220 stakeholders (6 international and 214 domestic) for research and education activities that require genetic diversity or genetic standards.
