Biology Reference
In-Depth Information
Results
Environmental Regulation of Flowering in Two EB Genotypes
of Wild Strawberry
We studied the effect of photoperiod and temperature on flowering time in two
EB genotypes, 'Baron Solemacher', which contains recessive alleles in SFL locus
[40,41], and 'Hawaii-4'. Flowering time was determined by counting the number
of leaves in the main crown before formation of the terminal inflorescence. In SD
genotypes of the wild strawberry, SD (<15 h) or, alternatively, low temperature
(~10°C) is needed to induce flowering [27]. In EB genotypes 'Baron Solemacher'
and 'Rugen', instead, LD and high temperature has been shown to accelerate gen-
erative development [35], but careful analysis of the environmental regulation of
flowering induction has so far been lacking.
Both 'Baron Solemacher' and 'Hawaii-4' produced five to six leaves in LD
at 18°C before the emergence of the terminal inflorescence showing that they
are very early-flowering in favorable conditions (Figure 1A and 1B). In 'Baron
Solemacher', low temperature (11°C) or SD treatment for five weeks at 18°C
clearly delayed flowering, but low temperature did not have an additional effect
on flowering time in SD. Also in 'Hawaii-4', SD and low temperature delayed
flowering, but all treatments differed from each other. Compared to the corre-
sponding LD treatment, SD at 18°C doubled the number of leaves, and low tem-
perature (11°C) delayed flowering time by about three leaves in both photoperi-
ods. Thus, flowering induction in these EB genotypes is oppositely regulated by
photoperiod and temperature than previously shown for the SD genotypes [27].
Figure 1.
Environmental regulation of flowering in everbearing wild strawberries.
The effect
of photoperiod (SD 12 h, LD 18 h) and temperature (11/18°C) on the flowering time of 'Baron
Solemacher' (A) and 'Hawaii-4' (B). Seeds were germinated in LD at 18°C, and seedlings were exposed to the
treatments for five weeks, when the cotyledons were opened. After treatments, plants were moved to LD at
18°C and flowering time was recorded as number of leaves in the main crown before the terminal inflorescence.
Values are mean ± SD. Pairwise comparisons between the treatments were done by Tukey's test, and statistically
significant differences (p ≤ 0.05) are denoted by different letters above the error bars.
