Browsing by Subject "kukintainduktio"

Fragaria x ananassa is a widely appreciated berry with its production growing all around the world. Thus, there will be a huge demand for strawberry breeding in the future especially since the climate change is casting an extra shadow upon the growing conditions which is also why there is a need for better understanding of different cultivar types. There are everbearing and seasonally flowering cultivars of both Fragaria x ananassa and Fragaria vesca. The seasonally flowering types such as ʻHapilʼ flower once during the growing season whereas everbearing types such as ʻCalypsoʼ flower for a longer period. The gene behind the change in the flowering habit has been tracked to the photoperiodic pathway of F. vesca although the gene behind the trait in F x ananassa remains unknown. The aim of this project was to compare flowering and vegetative responses of in vitro propagated everbearing F x ananassa cultivar ʻCalypsoʼ and seasonally flowering ʻHapilʼ in long and short day photoperiodic conditions in order to find out differences between everbearing and seasonally flowering cultivars. This was done by collecting data from phenotype observations linked to the vegetative and generative stages of the development of strawberries. The phenotype data was then combined with gene expression data of FaSOC1, FaTFL1, FaGA20ox4 and FaAP1 which are genes known to work on the photoperiodic pathway that regulates the switch between the vegetative and generative development of both F x ananassa and F. vesca. In addition, the expression of an everbearing phenotype associated gene FaFT2 was analysed. This study was a part of a larger project aimed to find out the genetic basis for the everbearing habit of F x ananassa. Part of the ʻCalypsoʼ plants were induced to flower already during the acclimatization period and the rest at the very beginning of the treatment period which then caused differential flowering times between the ʻCalypsoʼ groups. Short day grown ʻHapilʼ was induced to flower between weeks three and six whereas long day grown ʻHapilsʼ remained vegetative. Phenotypic observations were also backed up by the expression of FaTFL1 and FaAP1. Instead the FaSOC1 expression was repressed in short day conditions more than in the long days regardless of the cultivar type. ‘Calypsos’ were capable of producing runners regardless of photoperiod or flower induction. Consequently the runner production seemed to be regulated by factors outside of the photoperiodic pathway. However, the expression of runnering associated FaGA20ox4 was low and variable due to the sampling strategy. Interestingly most of the axillary meristems of short day grown ‘Hapils’ remained dormant for an unknown reason. Expression of FaFT2 was low on the apical meristems and further support for the role of the gene in everbearing phenotype was not found.

The aim of this research was to find out the effect of photoperiod and quantity of light on growth and flowering of arctic bramble (Rubus arcticus L.) cv. Mesma. The object was also to find out the effect of light on development of floral organs in apical buds of root suckers. Three 12 week long standard treatments were: LD (long day, 12 h HPS-light + 12 h incandescent light), SD (short day, 12 h HPS-light) and HPS (24 h HPS-light). Additionally, the effect of changing the light conditions was examined in four treatments: SD->LD (6 wk SD-treatment + 6 wk LD-treatment), SD->HPS (6 wk SD-treatment + 6 wk HPS-treatment), HPS->SD (6 wk HPS-treatment + 6 wk SD-treatment) and HPS->LD (6 wk HPS-treatment + 6 wk LD-treatment). In standard treatments the vegetative growth determined as the dry weight of the shoots was increased in HPS and decreased in SD. Elongation of shoot was enhanced by LD and development of new leaves was increased in LD and HPS. The number of flowers was highest in HPS and lowest in SD. The average dry weight of a flower and the number of flowers in relation to vegetative growth were increased in HPS. In SD growth and flowering were suppressed towards the end of the experiment. When plants were moved from SD to HPS or LD, growth and flowering were continued. Growth and flowering were clearly enhanced by continuous HPS light. Cessation of growth and flowering in SD suggests that the plants were becoming dormant. Growth and flowering continued when plants were moved from SD to LD or HPS, which indicates that plants were not fully dormant. The differences between treatments LD and SD were probably a consequence of dormancy induction in SD. Floral initiation in apical buds of root suckers occurred in all three standard treatments regardless of photoperiod or quantity of light.