Location: Tropical Plant Genetic Resources and Disease Research
2018 Annual Report
Objectives
The long-term objective of this project is to provide high quality management and curatorial care of the NPGS tropical/subtropical crop collection at the USDA, ARS, Daniel K. Inouye U.S. Pacific Basin Agricultural Research Center (PBARC), Tropical Plant Genetic Resource and Disease Research Unit (TPGRDRU), Hilo, Hawaii. The Hilo repository is physically located on the University of Hawaii, Waiakea Experiment Research Station. Emphasis will be placed on evaluation of the local collection to identify potential gaps and evaluate potential diseases to facilitate transportation/distribution of disease-free plant material; improvement of management practices to advance efficiency of conservation through cooperation with other ARS locations in Beltsville, Fort Collins, Mayagüez, and Miami; and documentation of universal descriptor data and best management practices for U.S. subtropical/tropical fruit and nut genetic resources. Specifically, during the next five years we will focus on the following objectives.
Objective 1: Efficiently and effectively acquire Pacific tropical and subtropical fruit and nut genetic resources, maintain their safety, genetic integrity, health and viability, and distribute them and associated information worldwide.
Subobjective 1A: Efficiently and effectively conserve and distribute tropical fruit genetic resources and associated information, emphasizing important crop plants and relatives of the primary crops assigned to the Hilo repository.
Subobjective 1B: Implement “quarantine-safe” germplasm transfer systems to transfer and back-up the NPGS-Miami avocado and NPGS- Mayagüez cacao collections.
Subobjective 1C: Develop long-term storage methods for papaya and pineapple.
Objective 2: Develop more effective genetic resource maintenance, evaluation, and characterization methods and apply them to priority Pacific tropical and subtropical fruit and nut genetic resources. Record and disseminate evaluation and characterization data via GRIN-Global and other data sources.
Subobjective 2A: Develop and evaluate emerging crops such as cacao, pili nut and breadfruit for increased cultivation in U.S. subtropical and tropical areas.
Subobjective 2B: Improve propagation and hybridization of pili nut, breadfruit, guava and macadamia nut.
Subobjective 2C: Develop genomic tools for genetic characterization of collection.
Subobjective 2D: Identify, mitigate and manage emerging diseases for sub-tropical and tropical fruit and nut crops.
Objective 3: With other NPGS genebanks and Crop Germplasm Committees, develop, update, document, and implement best management practices and Crop Vulnerability Statements to efficiently and effectively protect the safety, health, and genetic diversity of the U.S. tropical and subtropical fruit and nut genetic resource collections and associated information.
Approach
Subobjective 1A: 1) improve maintenance procedures for our crops to ensure that accessions are maintained as securely as possible given the resources available; 2) survey existing private and public domestic collections to determine if the germplasm they contain would make a valuable addition to the existing collection; and 3) improve distribution procedures to facilitate access to the collection. Duplication of the living collections and procedures for backup storage of seed are in place or in progress for most species.
Subobjective 1B: Create back-up collections for avocado and cacao in Hilo, using a quarantine procedure that will prevent the transfer of pests. Any material found to be infected with pathogens or other pests will be destroyed immediately.
Subobjective 1C: Develop protocols for long term storage of the papaya and pineapple collections by assessing the viability and longevity of material stored in liquid nitrogen. If pineapple cryopreservation is unsuccessful, the collection will continue to be maintained in both the greenhouse and tissue culture facilities at Hilo. If papaya cryopreservation does not extend the storage of papaya seeds, papaya seeds will continue to be regenerated at current frequency and stored at locally at two separate locations.
Subobjective 2A: Evaluate breadfruit, cacao and pilinut accessions for fruit production and qualities. If any fruit or nut samples for evaluation can’t be collected or processed properly due to weather or other protocol failures, the evaluation will be repeated in future years. Pili nut, breadfruit, guava and macadamia nut are important crops, but basic techniques for propagating and/or hybridizing them still need to be developed.
Subobjective 2B: Develop and document clonal propagation techniques for pili nut, breadfruit, and guava, and to develop a technique for making controlled crosses in macadamia. We will modify our propagation techniques in a stepwise process based on which parameters seem to be most important for successful propagation.
Subobjective 2C: Develop SNP markers through collaborators for rambutan and pulasan. If markers are not successful in detecting redundancies in the collection or sequencing is sufficient to generate a reference genome, further sequencing or different molecular marker techniques will be explored.
Subobjective 2D: Systematically evaluate and characterize emerging disease responses of tropical crops, to understand the host-pathogen interactions, and develop rapid methods for detection of pathogens. If insufficient information is found within our selected crops at the germplasm repository, symptomatic trees will be identified through communication with commercial nurseries, research stations, and private residences.
Objective 3: We will work with other repositories, scientists and industry to development of best management practices and develop Crop Vulnerability Statements. If external (national or international) assistance is unavailable, the team will focus upon local stakeholder groups to develop locally applicable methods and statements.
Progress Report
This report documents progress for this new project which began in March 2018 and continues the research of 2040-2100-014-00D, “Pacific Tropical/Subtropical Fruit and Nut Genetic Resource Management and Sustainable Production Systems”. For additional information, see the report for the previous project. This project is relevant to the NP301 Action Plan Component 1: Crop Genetic Improvement: Problem Statement 1A: Trait discovery, analysis, and superior breeding methods; contributing to NP 301 action plan: well characterized genetic mapping populations, mutant lines, and other germplasm designed for trait discovery, analyses, and increasing genetic diversity in crop plants.
Objective 1: Efficiently and effectively acquire Pacific tropical and subtropical fruit and nut genetic resources, maintain their safety, genetic integrity, health and viability, and distribute them and associated information worldwide. Three accessions of avocado were acquired from the University of Hawaii Kona station. One papaya accession was donated from a local grower. University of Hawaii cooperators donated one ohelo and one longan accession. One guava accession was received from Florida. Nine cacao accessions were received from local growers, and three species of Vasconcellea and two accessions of guava were purchased. Twenty-nine requests for 161 items were filled. Eight accessions of papaya were sent to Plant Developmental Genetics, University of Zurich, Switzerland; twenty-three accessions of rambutan were sent for genetic analysis; nine accessions of papaya relative seeds were sent for grow-out for genetic characterization; eight accessions of macadamia were sent for genetic characterization. Eleven accessions of avocado were introduced from the National Plant Germplasm System (NPGS) in Miami, Florida, through Fort Detrick, Maryland. Testing for Laurel wilt and Avocado Sun Blotch Viroid in Hilo was negative for all samples. For long-term storage method for pineapple, potential accessions are being tested for Pineapple Mealybug Wilt associated virus and will be multiplied. Papaya seeds from eight accessions have been shipped to ARS Fort Collins, Colorado, for cryopreservation longevity tests.
Objective 2: Develop more effective genetic resource maintenance, evaluation, and characterization methods and apply them to priority Pacific tropical and subtropical fruit and nut genetic resources. Negotiations with cooperators have begun and material is being propagated for field trials of new cacao varieties from ARS Miami, Florida, at three locations on Hawaii. Five accessions of breadfruit were successfully propagated by cuttings made of mature and immature, girdled branches and ten accessions of guava were successfully rooted from green, and hardened cuttings. Pineapple, macadamia and papaya relative plant material for genomic studies is frequently provided. Host-pathogen interaction field surveys of macadamia began at the germplasm repository and a new Phytophthora species causing disease symptoms was identified. Molecular testing capacity for Phytophthora spp. was established.
Objective 3: With other NPGS genebanks and Crop Germplasm Committees, develop, update, document, and implement best management practices and Crop Vulnerability Statements to efficiently protect the safety, health, and genetic diversity of the U.S. tropical and subtropical fruit and nut genetic resource collections and associated information. The ARS cacao collection founder visited and provided best practices and important descriptor data to implement the on-going cacao trials.
Accomplishments
