The Role of Grafting for Local Tomato Production in High Tunnels

The production of vegetables in high tunnels is changing the way specialty crops are grown in the United States. High tunnel technology is being rapidly adopted in regions where growing conditions may be difficult such as the Central United States in order to protect high-value crops from storms and damaging winds. High tunnels can also provide season extension opportunities and protect the crop from early and late frost events. However, soilborne disease management can be challenging in these systems due to the limited growing space that they afford. Grafting tomatoes with disease-resistant or vigorous rootstock is common worldwide for protected crop production and is gaining popularity in the US. Research was conducted in Kansas to determine the viability of grafting for peri-urban and urban (aka "local") high tunnel growers where little soilborne disease pressure was evident. When grafted with 'BHN 589' scions, 'Maxifort', 'Arnold' and 'Colosus' rootstocks significantly increased marketable and total fruit yield as compared to non-grafted 'BHN 589'. In contrast, 'RT 1028' and 'RST-04-106' rootstocks consistently showed no effect on crop yield. Fruit quality studies showed that brix level in the fruit was similar across treatments, but titratable acidity was significantly affected by rootstock (P<0.05). Similarly, antioxidant capacity was higher when 'RT 1028' and 'RST-04-106' rootstocks were utilized at one site when measured with ORAC. As high tunnel technology continues to grow and evolve in the US, the role of grafting with vigorous and disease resistant tomato rootstocks will continue to be a critical component for sustainable and organic production.