Training Truffle Growers to Optimize Field and Laboratory Techniques for Increased Production

Commodities

• Miscellaneous: mushrooms

Practices

• Crop Production: crop improvement and selection
• Education and Training: workshop
• Soil Management: soil microbiology

European truffles are a high-value specialty crop, with varieties such as the black Périgord truffle selling for over $1,000/pound. Truffles are the fruiting bodies of fungi that form symbiotic relationships with the roots of specific tree species. Because truffles typically do not appear until at least seven years after orchard establishment, it is critical that growers routinely evaluate tree roots to ensure continued colonization by the desired truffle species. Currently, root samples must be sent to specialized laboratories, a process that is time-consuming, costly, and often discourages growers from testing. This can lead to delayed, reduced, or failed truffle production.

To address this issue, the University of California Cooperative Extension (UCCE) will lead a train-the-trainer workshop in collaboration with NATGA and truffle experts from other universities. This program will teach growers, orchard consultants, and UCCE farm advisors how to evaluate truffle root colonization using two complementary approaches.

First, participants will learn how to properly select roots and identify key morphological traits under a dissecting microscope to distinguish truffle mycorrhizae from other ectomycorrhizal fungi. Second, the program will test and validate the use of Flinders Technology Associates (FTA) cards for genetic analysis. FTA cards, commonly used in other scientific disciplines, provide a low-cost, non-destructive way to collect and preserve DNA.

The workshop will be recorded and made available to the broader truffle growing community through the UCCE and NATGA websites. By implementing this workshop, UCCE and its partners will build local expertise in truffle root evaluation, enabling more frequent and affordable testing. This approach will save growers time and money, equip growers with the skills to examine more trees than they would otherwise test using a lab, improve orchard management decisions, and ultimately increase the profitability and sustainability of truffle production in the United States.

This project will focus on four objectives for increasing the knowledge, skills, and technical capacity of growers, orchard consultants, and extension agents on performing root tip evaluations using morphological identification and FTA-based DNA sampling.

• Objective 1: Equip growers with the knowledge of proper field sampling techniques for morphological root tip analysis and procedures for cleaning, processing and analyzing root samples using a dissecting scope.
• Objective 2: Teach stakeholders how to distinguish between Tuber and non-Tuber ectomycorrhizal root tips using morphological characteristics using dissecting microscopes.
• Objective 3: Teach stakeholders root tip testing via FTA cards (root tips pressed onto FTA card) for identification of Tuber
• Objective 4: Develop instructional videos for stakeholders (county extension agents and truffle growers) on identifying root tips to genus (species of Tuber), preparing root tips for pressing onto FTA cards, and FTA card use and handling.
• Objective 5: Influence management strategies that result in increased yield through increasing the capacity of growers to evaluate orchard roots. Although this objective will not be measurable in the project timeline, we will continue to monitor this goal.