Vol. 83 No: 5

Title:
Flowering physiology of populations of Fragaria virginiana

Authors:
A. SØNSTEBY and O.M. HEIDE

pp: 641-647

Abstract:
The environmental control of flowering in five populations of Fragaria virginiana ssp. glauca and three populations of F. virginiana ssp. virginiana (henceforth referred to as F. virginiana), obtained as seed from the National Plant Germplasm Repository, Corvallis, OR, USA, has been studied under controlled environment conditions. Except for the F. virginiana ssp. glauca population PI 551648 from the Wasatch Mountains in Utah, which was truly day-neutral across a 9° – 27°C temperature range, all the other populations of both sub-species behaved as quantitative (facultative) short-day (SD) plants with earlier and more abundant flowering under SD than under long-day (LD) conditions. Flowering of the remaining F. virginiana ssp. glauca populations was governed by a significant interaction of photoperiod and temperature. The SD dependence for flowering increased with increasing temperature from 9°C to 27°C. The optimum temperature for the SD flowering response was 15° – 21°C.While SD promotion of flowering was more pronounced in the F. virginiana populations, temperature had no significant main effect on flowering in this sub-species, demonstrating a wide temperature tolerance for flowering.Vigorous runner formation was observed in all populations, in both SD and LD, with a highly significant advancement effect of increasing temperature.The flowering and runnering responses of these F. virginiana populations are discussed in relation to their putative paternity of perpetual-flowering F. × ananassa cultivars. It is concluded that, with the complex inheritance in these octoploid plants, the flowering responses of the populations studied here are not reflected in the LD flowering response of cultivated everbearing strawberries.

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