Garlic is an important crop for organic vegetable growers and small seed companies in Oregon and California. Some farmers increase economic value by processing garlic into braids, pestos, powders and salts. Garlic grows during Oregon’s wet season (planted October, harvested July) so is a crop that can be grown even with increasingly scarce late season water availability. If organic garlic is to increase its market share, garlic varieties suited to this region with resistance/resilience to garlic rust and other diseases and problems must be identified. Garlic rust became a significant problem in California in 1998, reducing yields by up to 50% and soluble solids by 15%. California organic farms control rust through spatial rotation, sanitation, and marginally effective sulfur applications; rust reduces yields there by 25-50%. Rust was sporadic in Oregon before 2010 but now reduces yields by up to 40%. Fusarium basal rot is a significant disease in California. While less important in cooler Oregon, 10-20% damage was observed in Oregon fields in 2014 and 2015.
Seed savers, garlic farmers, and garlic seed producers (Garlicana and Deerfield Farm) have been evaluating garlic germplasm in this region. While garlic primarily reproduces clonally/asexually, some types reproduce sexually (true seed); Garlicana and Deerfield have been growing and selecting garlic from true seed for regional performance but not disease resistance. Variety trials were conducted in CA in the 1990s to identify rust resistant garlic varieties but no significant resistance was identified in the varieties tested. Research in Spain and Colorado identified rust resistance and Wisconsin research identified Fusarium basal rot resistance in USDA NPGS garlic germplasm; rust resistance was identified in varieties derived from seed of NPGS germplasm.
The goals of this project are to:
1: Identify and collect garlic varieties/germplasm with organic market, disease resistance, and storage potential
2: Engage farmers, seed growers, and buyers in the development of garlic evaluation criteria for diverse uses and markets
3: Screen garlic varieties/germplasm for disease resistance and other evaluation criteria developed in Objective 2.
4: Engage organic garlic growers and buyers in project findings.
Seed stock of at least 100 garlic varieties/accessions will be accessed from: USDA NPGS (National Plant Germplasm System); Deerfield Farm (tissue-culture); Garlicana (clonal and true-seed); Other seed/farm sources; and Seed Savers Exchange. Through discussions at meeting one (and pre-meeting surveys of farmers and buyers), garlic uses, markets, and evaluation criteria will be described.
Varieties will be evaluated in replicated experiments in one location in California and two locations in western Oregon. Disease severity and other measurements/photos will be taken as determined by the evaluation criteria. Bulbs and cloves will be weighed and photographed. Garlic will be stored and percent rotten, sprouted, and desiccated bulbs will be evaluated monthly.
Project farmers will interact with and taste garlic and discuss project findings at three winter meetings. Other farmers/buyers will interact with varieties and learn about results through booths, tastings, presentations and workshops: A report including photos/descriptions of high performing varieties and an article on the diagnosis and management of diseases and other problems will be published to oregonvegetables.com. An article describing best-performing varieties will be published through eOrganic (http://articles.extension.org/organic_production) for a broader audience.
We anticipate that farmers will increase their understanding of garlic varieties and their uses, markets and performance, as well as their knowledge of garlic problems and their management. They will adopt new garlic cultivars to improve performance and/or add uses/markets.
Rust and Fusarium basal rot resistant varieties should increase garlic yield, quality, and profitability, thereby increasing economic sustainability. If garlic was higher yielding and more profitable it could grow in acreage in California and become a profitable wholesale crop in Oregon. As garlic can be grown dryland it can be grown in areas with increasingly limited late season water, increasing farm resilience and environmental sustainability. While this project is primarily directed at organic farmers as they are currently unable to control rust and organic fungicides are not very effective, conventional farmers are seeking resistant varieties to reduce fungicide applications; reducing fungicide applications on organic and conventional farms will improve economic and environmental sustainability. Improving farm profitability increases farmer quality of life and the social sustainability of agriculture.
Objective 1: Identify and collect garlic varieties/germplasm with organic market, disease resistance, and storage potential
Objective 2: Engage farmers, seed growers, and buyers in the development of garlic evaluation criteria for diverse uses and markets
Objective 3: Screen garlic varieties/germplasm for disease resistance and other evaluation criteria developed in Objective 2.
Objective 4: Engage organic garlic growers and buyers in project findings.
Garlic seed was accessed from multiple sources including commercial garlic seed sources (49 accessions) and the USDA Germplasm Repository in Pullman, WA (90 accessions).
Four replicated trials of the 49 commercial accessions (4 replications, at least 6 plants per replication) were established in October 2017 at 1) the OSU Vegetable Research Farm in Corvallis, OR, 2) Phil Foster Ranch in Hollister, CA, 3) Gathering Together Farm in Philomath, OR, and 4) White Oak Farm in Albany, OR. The 90 USDA accessions were grown up at the OSU Vegetable Reesarch farm for planting in replicated trials in 2018-19.
In 2018, all 49 commercial accessions and 90 USDA accessions were planted in replicated trials in 3 locations: 1) the OSU Vegetable Research Farm in Corvallis, OR, 2) Gathering Together Farm in Philomath, OR (for rust evaluation), and 4) White Oak Farm in Albany, OR (for white rot evaluation).
Rust incidence was extremely low at Phil Foster Ranch so there were no significant differences in rust in that trial. Rust severity was moderate at Gathering Together Farm. White Turban, Jade Rose, Sakura, Russian White, and Cuzco matured and were harvested early, thereby escaping severe rust damage. Rust severity in Shvelisi, Surak, Kishlyk and Anarres (varieties of lowest severity) was significantly lower than in Pyongyang, Hadrut, Navistar, and Northern White (varieties of highest severity). Unexpectedly, there was white rot in the trial at White Oak Farm. Even more unexpectedly, while most plants were killed by the white rot fungus, all plants of one variety (Khabar) survived.
In both the OSU and GTF trials there were significant differences in bulb size. The varieties with the largest bulbs were Donastia Red, Duganski, Metechi, Brown Rose, Beekeeper’s Sicilian, Music, German White, Siskiyou Purple, Khabar, Vekak, Polish White, and Northern White.
Educational & Outreach Activities
In December 2018 a full day workshop was held. Ten garlic seed growers, 6 garlic farmers, and 10 agricultural professionals attended. Topics addressed included disease and insect pest diagnosis and management, results from variety trials, and differences in garlic type quality, storage and uses. Participants observed garlic mites through a high powered dissecting scope.
In preparation for the workshop, a draft of an extension publication on garlic types and uses was developed and distributed at the workshop. This publication will be further developed for publication in 2019