Crop Load Adjustment Based on Tree Vigor for Producing Uniform Fruits in ‘Niitaka’ Pear Trees

초록

The trials were performed to find out certain cultural techniques for producing uniform fruits with even quality as well as even size with the use of ‘Niitaka’ pear trees (Pyrus pyrifolia Nakai) from 2004 to 2006. Appropriate ratio of total scaffold cross-sectional areas (SCAs) to trunk cross-sectional area (TCA) was investigated and a certain crop load method applied with the consideration of that ratio for uniform fruits. The ratio of total SCAs to TCA kept around 1.0–1.2 regardless of the number of scaffolds. While vegetative tree growth was hardly affected by the ratio of total SCAs to TCA, reproductive growth was improved at the tree with the ratio of 0.8 to 1.2 or above 1.2. Fruit size tended to be affected by the ratio of total SCAs to TCA, but fruit quality seemed to be scarcely affected. The obtained result indicated the suitable crop density (fruit number/cm2 TCA) and yield efficiency (fruit yield/cm2 TCA) as 1.0 to 2.0 fruits/cm2 TCA and 1,000 to 2,000 gácm2 TCA. Adjusting crop load with the consideration of proper crop density improved the uniformity in fruit weight as narrowing frequency distribution but hardly reformed the uniformity in total soluble solids.

키워드