Correlative Bud Inhibition and Growth Habit of the Strawberry as Influenced by Application of Gibberellic Acid, Cytokinin, and Chilling during Short Daylength

Abstract

In axillary meristems laid down just prior or subsequent to commencement of growth regulator applications, exogenous gibberellic acid (GA) alone promoted runner formation. Strongly-inhibited axillary buds with leaf primordia responded to GA + BA (benzyladenine) with runner formation in the June-bearer ‘Fortune’. Few of the inhibited buds of the everbearer ‘Geneva’ responded to GA or GA + BA. Following application of BA alone, inhibited buds of June-bearing cultivars formed lateral crowns (‘Fortune’) or runners (‘Earlidawn’). Runner formation following chilling of June-bearing ‘Fortune’ plants exposed to short days (SDs) occurred from meristems initiated after satisfaction of the cold requirement. Comparable buds on plants receiving no chilling during SDs remained inhibited, as did axillary meristems present during SDs. In contrast, runners formed by chilled, everbearing ‘Geneva’ plants originated from axillary meristems initiated prior to chilling but not from subsequent meristems. Chilling ‘Geneva’ plants during exposure to SDs removed the inhibition from existing axillary meristems and promoted runner formation. Runnering did not occur in activley growing ‘Geneva’ plants maintained under long days (LDs).