INFLUENCE OF ORCHARD SITE PARAMETERS ON F RUIT-QUALITY OF FUJI APPLE

To elucidate the influence of orchard site parameters on fruit quality of 'Fuji' apple grafted on M. 26 rootstock, the crops from 41 orchard s located about Shiwa Town, Iwate Prefecture, Japan were analyzed by t he quantification theory (1) 1. High positive correlations were found among total sugar content, titratable acid content, and fresh firmness . Principal component analysis applied to the three characteristics re vealed that the first component represented fruit quality, whereas the second, apparent fruit maturity. The orchard site parameters seemed t o affect the two components in different ways. The more solar radiatio n to which the apple trees were exposed, the higher was their fruit qu ality. On apparent fruit maturity, however, soil texture had greater i nfluence than the quantity of solar radiation. 2. Contents of each sug ar were also analyzed by principal component analysis, based on their significant correlations. The first principal component represented to tal sugars, whereas the second component was the difference between re ducing sugar and nonreducing sugar contents. The first component made a major contribution to the difference in total fruit sugar contents a mong the orchards. Because orchard site parameters affected the first component somewhat differently from that on the second component, they may have influenced fruit sugar composition. 3. Oxidation (browning) of the juice was closely related to the soil type of the orchard. The juice of fruits harvested from trees grown on volcanic ash and alluvia l soils did not brown as fast as juice of fruits collected from trees grown on red-yellow soils. The browning tendency was seemingly related to the soil nitrogen content.