2011 Volume 10 Issue 2 Pages 173-181
We assessed runner production in everbearing strawberry cultivars (Fragaria × ananassa Duch.) ‘Natsuakari’ and ‘Dekoruju’, which exhibit poor ability to produce runners, thus limiting their propagation and use. Both cultivars required 1,000 h of chilling (< 5°C) to induce runner production when grown under a long day length (LD); however, they required longer chilling under a short day length (SD). Plants chilled for 2,000 h tended to produce more runners under SD than under LD. During spring and summer, the overwintered ‘Natsuakari’ plants produced the fewest runners under SD. In contrast, the overwintered ‘Dekoruju’ plants produced the fewest runners under LD. Thus, a longer day length did not always enhance runner production in these cultivars. In autumn, 90-day cold storage at −2°C was substituted for natural chilling for plants that were rooted in summer. For both cultivars, the production of runners by plants that were rooted in July was similar to or greater than that by plants that were rooted in May. The rooting of mother plants in July, which are more available than plants rooted in May, did not have a detrimental effect on runner production during the next early summer period. Considering total runner production till July, we concluded that it is appropriate to initiate cold storage in December for the ‘Natsuakari’ cultivar and in November or December for the ‘Dekoruju’ cultivar.
