Comparison of Fruit Development and Quality Indices According to Blossom Thinning on Early-season 'Hanareum' and Mid-season 'Niitaka' Pears

摘要

In this study, we evaluated the differences in fruit development and quality indices of fruits subjected to blossom thinning before full bloom in 'Hanareum' and 'Niitaka' pears (Pyrus pyrifolia Nakai). We carried out a thinning treatments at 5 days before full bloom, targeting the blossoms at the 1st and 2nd position (T1) or the blossoms at the 6th and 7th position (T2) from the basal part of the flower cluster in both cultivars. Blossom thinning treatments increased the average fruit weight of early-season Asian pear 'Hanareum' up to 10.5% (T1) and 11.0% (T2) at harvest time (no days after full bloom). The mid-season 'Niitaka' pear showed increased fruit weight of tip to 12.6% (T1) and 16.8% (T2) at harvest time (170 days after full blown). Moreover, these treatments increased the production rate of bigger sized fruits in both cultivats. Removal of blooms also affected fruit quality indices; the bloom-thinned fruits showed higher soluble solids contents (about 1 degrees Brix) and higher skin color redness (a*) especially in 'Niitaka' pears when compared to the non-thinned controls. Overall, the treatments increased the fruit size and weight as well as fruit quality including soluble solids and skin color. Bloom thinning treatment targeting the 6th to 7th blossom from the basal part of the flower cluster may be recommended as the practical thinning method in Asian pear 'Hanareum' and 'Niitaka'.