Yield and fruit quality of Japanese pear in "Joint V-shaped trellis"
The cultivation area of Japanese pear (Pyrus pyrifolia Nakai) is decreasing in Japan, partly because of a shortage of new growers and difficulty associated with replanting and the long time required to establish mature orchards. We have invented a new technique called the Tree joint training system that is a labor saving method of rapidly establishing a new flat trellis orchard and involves planting young trees linearly and connecting adjacent trees by grafting to make a long series of trees. This method is being used to extend the Japanese pear production area in Japan. For years, Japanese pear production has been conducted using the flat trellis approach with low tree density. To break the limit of flat trellis productivity and introduce mechanization or robotics applications, we have improved the original Tree joint method into a new system called Joint V-shaped trellis. In this system, lateral branches are trained to the trellis in upward directions to make a V-shaped canopy. Planting density is 1667 trees ha‑1, height of scaffold branches is 0.8 m, and angle of lateral branches is 60°. We compared yield, fruit quality, tree growth, and yield efficiency between joint V-shaped trellis and a similar system of Y-shaped trellis of the primary cultivar 'Kosui' in the first year of harvest. In joint V-shaped trellis, the yield at first harvest in the third year after planting was about 11.6 t ha-1 and exceeded Y trellis by 1.5 t ha-1. Average fruit weight in joint V-shaped trellis was 395 g, significantly higher than Y trellis. As for the distribution of fruit quality within trees, variance of fruit weight and hardiness along the height of lateral branches was small and no reduction in quality was observed at the bottom of lateral branches. In Y trellis, however, the mean weight of fruit harvested from above 1.8 m was smaller and fruit harvested between 1.4 and 2.4 m were firmer. We discuss differences between these two systems from the viewpoint of tree structure, tree growth, yield, crop load, and fruit quality distribution.
Seki, T., Hirose, K. and Shibata, K. (2021). Yield and fruit quality of Japanese pear in "Joint V-shaped trellis". Acta Hortic. 1303, 171-176
Pyrus pyrifolia, Y-shaped trellis, planting density, crop load, yield