Abstract
Fruit quality was quantitatively expressed by pressure resistance, refractometer readings, pH value of juice and weight of fruit in lieu of texture, sweetness, sourneess and fruit size, respectively. Statistical analyses were made on cultivar populations with respect to environmental variations which manifest themselves on individual fruits and trees as well as inter annual variations.
Year to year variation was great in fruit weight and refractometer readings, and such variation was small for pressure resistance and the pH value of juice. Sampling errors estimated were extremely great for fruit weight compared with the other characteristics.
The quality of Chojuro fruits collected from different regions indicated some variation in pressure resistance and pH value of juice.
Comparing recent cultivars with old ones, it clarified that the results of quality improvement are more evident for fruit texture, expressed by pressure resistance, than for any other characteristics.
