1980 Volume 49 Issue 1 Pages 15-22
To evaluate three maturation characteristics (1. the fruit variance of maturation in a tree, 2, the maturation rate of an individual fruit, 3. the nature of dropping of matured fruit), and to determine the date and the period of harvesting more objectively, the random sampling method and the ground color pursuit method were planned. Ground color ratio curves (a changing pattern of fruit ratio in ground color grades with the passage of time on a tree) were illustrated from the ground color changes determined by both methods using color chart. Both the earliest and the latest start and end of harvest, the longest and the shortest harvesting period could be pointed out from these curves. Curves also seemed to reveal the cultivar-specific characteristics of fruit maturation. The width of lines indicated the maturing rate of an individual fruit. Individual fruits of Chojuro ripened fast and showed the narrow intervals of lines. The gradient of lines corresponded with the fruit variance of maturation in a tree. Fruits of Hosui, showing a steep gradient, ripened simultaneously. Chojuro bore fruits with the wide range of maturation from over-matured yellowed to immatured green fruits on a tree simultaneously, and showed the gentle slope of lines. In the period from the start of yellowing to the dropping, and in the ground color shade at the drop, cultivar differences were observed. The ground color ratio curves, drawn from two different methods described above, were so similar that whichever method was available according to the objective. Some discussions were made on the relations between above mentioned three maturation characteristics and the cultivar-specific harvesting methods and harvesting intervals.
