The relationship between bud dormancy and the fruit maturing period in satsuma mandarin

Abstract

Bud paradormancy or rest period of 13 cultivars of satsuma mandarin (Citrus unshiu M.) that differed in fruit maturing periods was evaluated by the days to bud break (DTB). The values of DTB were obtained by a forcing method. Paradormancy appeared to occur from September to October, with the highest value in late September, when the varietal differences were evaluated. The DTB was more than 21 days in the cultivars that matured by mid-November, including the very early, early fruit maturing cultivars, and 'Kunou unshiu'. Budbreak in late-maturing cultivars occurred within 21 days. Hence, the DTB values appeared to decrease as the fruit maturing period was delayed. It is cleared that there is a varietal difference in the depth of bud paradormancy that evidently is related with the fruit maturing period.