2018 ASHS Annual Conference

While tomato is important to global markets, it is also the iconic local vegetable, and consumers seek out the flavor of locally produced tomatoes. In Northern climates, production over a longer season is important to direct-market farmers. Farmers who have the first tomatoes at market can gain customers and keep them over the year. For this reason, many growers are using high tunnels to extend their season.

We compared a diverse set of varieties in high tunnel and field organic production environments. Our objectives were to determine if there was significant genotype by management system interaction for productivity, disease susceptibility and quality, in order to set breeding priorities for the two management systems. We also used data from the trials to compare different pricing scenarios for both early and late production for slicer and heirloom market classes. Labor hours were recorded to compare the cost of production for each system as well.

Management system had the largest effect on yield and disease, with the high tunnel producing 8.7 kg/plant compared to 5.1 kg/plant in the field, over all varieties and years. The incidence and severity of disease in the field was much greater than in the high tunnel. The average area under the disease progress curve was over four times greater in the field than in the high tunnel. Quality traits were more influenced by variety, although management also had an effect. Large slicers had the lowest ˚Brix value and flavor intensity, while heirlooms and small slicers had higher ˚Brix and flavor intensity. Flavor intensity was strongly correlated to preference.

While there was not significant genotype by management system interaction for yield or disease susceptibility, the traits required in each system were different enough to justify separate breeding projects. Breeding for early blight, septoria and bacterial speck resistance, combined with excellent flavor, is the top priority for field production. For high tunnels, pushing production even earlier while maintaining flavor is a top grower priority, and reducing susceptibility to blossom end rot and green shouldering is critical.

Some heirloom varieties would need to be priced considerably higher than slicers to have equivalent revenue, but we identified some very promising new varieties, selected to have the flavor of heirlooms with higher productivity. Labor hours were surprisingly similar between the two systems, confirming what growers have been demonstrating, that high tunnel tomato production can quickly pay off the structure and be highly profitable.