A comparative study of fruit quality was conducted in 'Saijo' ('S') and 'Hiratanenashi' ('H') Japanese persimmons. Fruits of 4 strains (Hinomisaki, Wase-B, Wase-Shimadai,Izumo) produced at several places of Shimane prefecture were supplied for the study in 'S' and fruits produced at 3 orchards of different districts (Yamagata, Osaka and Shimane) were supplied for it in 'H'.
(1) Degree of coloration in fruit skin surveyed by a color chart was distinctively different between the 2 cultivars; 5.67 in 'H' and 4.27 in 'S'. Among the 6 samples of 'S', Izumo produced in Shimane Agricultural Experimental Station depicted the highest color degree, 5.3. In this case, a reflective film coated with aluminum was used as the mulch of the orchard during the period of color development.
(2) As to the soluble solids content (Brix゜) in juice removed the soluble tannin by PEG, all samples of 'S' except 2 early maturing strains, Hinomisaki and Wase-B, showed high values exceeding the 16%, and were higher than all samples of 'H' by about 2%.
(3) As to the acid content in juice, all samples of 'S' and 'H' showed low values ranging from 0.04 to 0.07%.
(4) The rates of decrease in flesh hardness after the deastringency by dry ice were generally higher in 'S' than in 'H'. Among the samples of 'S', early
strains such as Hinomisaki and Wase-B, showed higher rates than the others.
(5) The soluble tannin content in juice were about 0.6% in all samples of 'S' and 'H' except Wase-Shimadai (0.95%) and a sample of Izumo produced at Experimental Farm of Shimane University (0.84%).
(6) The ranking in eating quality of all samples were as follows; the 1st: Izumo of 'S' produced at Shimane Agricultural Experimental Station, the 2nd: Izumo of 'S' at Expenmental Farm of Shimane Unrversity, the 3rd: Wase-Shimadai of 'S', the 4th: Izumo of 'S' at Mr. T's orchard, the 5th: Wase-B of 'S', the 6th 'H' at the orchard of Kyoto Universrty (Osaka), the 7th:' 'H' at Shimane University, the 8th: Hinomisaki of 'S' and the 9th: 'H' at Yamagata University. Thus, all samples of 'S' except Hinomisaki were better in eating quality than those of 'H'.
(7) In the fruits before the deastringency, the ratios of sucrose in the suger content in juice were 41.6% in 'S' and 22.4% in 'H'. Among the samples of 'S', 2 early strains, Hinomisaki and Wase-Shimadai, showed higher ratios of it. Among the samples of 'H', those obtained at the cooler regions, Shimane University and Yamagata University, showed a higher ratio of it (25%) than that at Kyoto University (15.7%).
(8) Due to the deastringency, the ratios of sucrose increased or decreased depending on the samples, and thus the effects of deastringency on them was not consistent.