モモ果実の渋味発生に及ぼす環状はく皮の影響

Abstract

Lateral bearing branches of two peach cultivars, 'Sanyo-suimitsu' grafted on Prunus persica or P. tomentosa rootstocks and those of 'Shimizu-hakuto' grafted on P. persica root- stock, were girdled at Stages 1 and 2 of fruit development. At harvest phenolic contents were determined and related to astringency. The relationships between phenolic content and fruit maturity and pit-splitting of fruit, were also investigated. Girdling advanced fruit maturation and increased fruit weight, except in 'Sanyo-suimitsu' grafted on P. tomentosa. Total soluble solids contents were higher in fruits from girdled branches ex- cept for 'Shimizu-hakuto'. Regardless of cultivar and rootstock, the total phenolic contents and fraction of higher molecular weight phenols were higher in fruits from girdled branches than in fruits from non-girdled branches. However, there was no consistent correlation between the girdling stage and phenolic content in the fruits. The earlier the fruit matured, the higher was the phenolic content, especially those on girdled branches. The exception were those fruits from non-girdled branches of 'Sanyo-suimitsu' trees grafted on P. tomentosa rootstock. There were little differences in phenolic contents between fruit with and without split pits, although girdling markedly increased the frequency of split pits.