To clarify the adaptability of blueberries as commercial fruit trees to San-in area, we have been growing the blueberry plants of 6 cultivars, each 3 of highbush ('Northland', 'Rancocas' and 'Jersey') and rabbiteye ('Woodard', 'Homebell' and 'Tifblue') types, since 1986 at a field of heavy soil in Honjo Experimental Farm of Shimane University. The results of comparative investigation on these plants until the 4th year after planting are summarized as follows.
In highbush blueberry, 'Northland' was most superior among the 3 cultivars in either plant growth or berry yield. The average hight and width of its plants in the 4th year were both 1.1 m and the average yield per plant in the year was 4.1 kg. These figures were much higher than those already reported by others investigating in the northern parts of Japan. The peak time of harvest in the cultivar was late June.
In rabbiteye blueberry, 'Tifblue' was most superior, and the average hight and width in the year were 1.7 m and 1.5 m, respectively, and the average yield in the year was 5.3 kg. Thus, 'Tifblue' was more vigorous and productive than 'Northland'. The peak time of harvest in 'Tifblue' was early August.
Even though the investigation was conducted in the young ages, the commercial growing of both highbush and rabbiteye blueberries in San-in area seems to be hopeful if suitable cultivars are employed. Further investigation should be continued for another several years until the adult age to obtain a reliable conclusion.