Evaluating Rootstock for Fresh Market Tomato Yield, Quality and Sustainability Tsedeniya Getahun, Harlene Hatterman-Valenti, Collin Auwarter Department of Plant Science, North Dakota State University Fresh market tomatoes are widely grown by specialty crop producers in North Dakota due to their profitability in the fresh market/local foods segment. However, with North Dakota's short growing season, growers often use high-tunnels for season extension to protect the crop from early and late frost events. Unfortunately, tomato plants often face numerous soil and disease challenges due to limited growing space in the high tunnel. Inadequate leaching of soluble salts in the soil and limited crop rotation contributes to salt and disease inoculum buildup in the soil that threatens the health of tomato plants and may cause serious losses in high tunnels. This two-year project with the first year completed in 2024, aims to evaluate the improvement of tomato production by grafting an heirloom, fresh market and paste tomato cultivar with excellent fruit quality characteristics onto rootstocks that are resistant to various abiotic/biotic stresses under high tunnel production. Tomato scion ‘Bigboy’, ‘Brandywine’ and ‘San Marzano’ (indeterminate), and ‘BHN 589’ (determinate) were grafted on to six rootstocks: ‘Arnold’ (generative), ‘DR0141TX’ (generative and vegetative), ‘Estamino’ (generative), ‘Fortimino’ (vegetative), ‘Maxifort’ (generative) and ‘Multifort’ (generative). Scion selection significantly influenced marketable yield, whereas rootstock had no significant impact. This effect was observed in ‘Big Boy’ but not in ‘San Marzano’ or ‘Brandywine’. ‘Big Boy’ grafted onto ‘Multifort’ or ‘Fortamino’ produced the highest marketable yield, followed by ‘Arnold’, Maxifort’, and ‘DR014TX’, with the lowest yield observed in non-grafted Big Boy’. ‘DR0141TX’ and ‘Multifort’ increased stem diameter and San Marzano tomatoes grafted onto Maxifort, Multifort, and Fortamino had the tallest plants. The trial will continue for another year to further evaluate the benefits of grafting for high tunnel tomato production in North Dakota.
