Elucidation of high-yielding factors and high-yielding production technologies of Eriobotrya japonica cultivated under protected pomiculture

To standardize the high-yielding production technologies of Erlobotrya japonica (loquat) cultivated under protected pomiculture, shoot management technologies, which are closely related to yield, were studied based on field surveys conducted for identifying the characteristics of trees in farms that bear high-yield production of 1.5 t or more per 10 a. 1. In high-yield farms which produce fruits of 1.5 t or more per 10 a, branch induction is carefully applied to the trees, by which the leaf area per 10 a becomes as great as about 2,500 square m (2.5 of LAI (leaf area index)) and the crown occupancy ratio is constantly kept at 80% or more. 2. To make Erlobotrya japonica cultivated under protected pomiculture produce high yields for consecutive years, tree management should be conducted by inducing lateral branches by small units and applying thinning-out pruning which reduces the wood sections while losing as few leaves as possible. 3. Regarding the Eriobotrya japonica called INagasaki Wasei cultivated under protected pomiculture, which is planted in a two-stage crateriform and produces a yield of around 1.5 t per 10 a, the LAI was 2.9 or higher on average; the number of branches per square meter of crown occupancy area was around 43; and the number of bagging was around 19. 4. When fruit-bearing shoots are cut back strongly, the bunch (flower) setting becomes unstable, resulting in delayed harvesting time and small-sized fruits. If fruit-bearing shoots must be cut back to keep the crown compact, it is recommended to leave at least 6 leaves on each shoot. 5. Fruits that set on the central branch are larger than those set on fruit scar branches. The correlation between the character of fruit scar branches and the weight of fruit per bunch was low. 6. In the case of trees planted in the two-stage crateriform at intervals by which branch tips only on one side overlap each other, the yield markedly decreased in the direction where the sunlight is intercepted, and the yield of the primary scaffold branch group on the first stage decreased by about 40% in comparison with trees planted one by one. 7. In June, compaction using wire was applied to the wood sections where no young shoots were coming out, which stimulated the emergence of adventitious buds.