2018 Volume 17 Issue 1 Pages 33-40
To apply summer-autumn flowering of highbush blueberry to two-season harvesting and autumn harvesting, we investigated the timing and degree of flowering in summer-autumn for 78 highbush blueberry cultivars. ‘Bluetta’, ‘Puru’, and ‘Bluecrisp’ flowered readily during the summer-autumn. Moreover, summer-autumn flowering was observed at the tip of shoots from mid-July to mid-November. The shoot lengths were around 70–100 cm. One-year-old branches that flower in summer-autumn differed among cultivars, for example, ‘Bluetta’, ‘Patriot’, and ‘Spartan’ flower from shoots and suckers, but ‘Bluecrisp’ flowers from shoots only. Inflorescences that flowered in the summer-autumn showed a form unlike that of inflorescences that flower in spring. These did not form flower fruit clusters, and there were individual florets located in each leaf axil of the shoot. Moreover, the number of florets per shoot was 3.9–4.8. The day temperature was slightly lower, the duration of sun light was shorter, and summer-autumn flowerings were more numerous in July 2013 than in 2014–2015. Moreover, temperatures in September and October in 2013 were higher. The results suggest that flowering during the summer-autumn is related to climatic conditions.
