Browsing by Author "Kymäläinen, Sonja"

The woodland strawberry (Fragaria vesca) exists almost in the entire Northern Hemisphere. Short daylength and low temperature induce flowering in autumn. Flowering begins in the next growing season when daylength becomes longer and temperature increases. The aim of this study was to find out the critical daylength for flower induction in woodland strawberry genotypes from different latitudes. The aim was to find out differences in vegetative growth, flowering and FT-gene expression between different genotypes in three daylengths. In this study ten different genotypes from different latitudes were used as the plant material. There were three daylength treatments; 12h, 14h and 16h. After six weeks of treatments plants were moved to greenhouse where the daylength was long (18h). In this study the number of stolons and crowns, petiole length, flowering time and the number of inflorescences were observed. In addition RNA was isolated from five genotypes and the expression of FT-gene was determined. The beginning of flowering depended on daylength and genotype. The northern genotypes began to flower soon after all treatments and they also formed more inflorescences than the southern genotypes. The southern genotypes flowered last and only after 12h and 14h treatments. FT-gene expression was noticed only in 16h daylength and the expression was the strongest in southern genotypes which didn´t begin flowering in this treatment. The petiole lengths were shorter in northern genotypes than in southern genotypes. The number of crowns depended on daylength. In 12h daylength there were more crowns than in 16h daylength. On the other hand there weren´t differences in the number of crowns between the genotypes. The critical daylength for flower induction depends on the latitude of the origin. The critical daylength for flower induction was noticed to be over 16h in Norwegian genotypes. The critical daylength for flower induction is over 14h but under 16h in Finnish and Central Europe genotypes. In southern genotypes the critical daylength for flower induction is over 12h but under 14h. Longer daylengths enhance vegetative growth except crown branching.