Yield of paste tomato cultivars using season extending high tunnel production practices in North Dakota’s short growing season

Season extension technology, such as high tunnels, enable farmers in short-season growing environments to expand their production timeline when compared to field production practices. Controlled environment horticulture using high tunnels also allows for warm-season crops to be grown more effectively where diurnal temperature shifts in field conditions might otherwise delay their development. Growing interest in the Northern Great Plains focused on tomato production is based on merging cultivar decisions with production practices that employ controlled environment conditions. To support this regional interest, high tunnel production capacity for nine paste tomatoes (‘Big Mama’, ‘Blue Beech’, ‘Cauralina’, ‘Gladiator’, ‘Granadero’, ‘Pozzano’, ‘San Marzana’, ‘Tiren’, and ‘Verona’) was evaluated during the 2019 and 2020 growing seasons in Fargo, North Dakota, USA. The experiment was conducted as a 9×2 factorial using three replicates per season to examine two factors, cultivar and number of tomato plant leaders retained (either one or two leaders per plant). Number of leaders affected both total fruit number per plant and total yield per plant. For plants with two leaders, yield and fruit number were both over 44% greater than plants with one leader. No cultivar × number of leader interaction was detected. Across the two years, ‘Cauralina’, ‘Gladiator’, and ‘Blue Beech’ all produced individual tomato fruit averaging more than 100 g each. ‘Verona’ produced the smallest fruit (45.2 g), but the greatest fruit number per plant (97.0). No differences among cultivars were detected for total yield. The average fruit size was 105.0 g per fruit across cultivars. Plants averaged a yield of 4364.8 g per plant across a mean of 44.2 fruits per plant. Continued work to improve high tunnel production practices in North Dakota focusing on irrigation and nutrient management for promising paste tomato cultivars should lead to increased yield for local farmers.