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Browsing by discipline "Kasvintuotantotieteet (puutarhatiede)"

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  • Pohjola, Minna (2013)
    Red raspberry (Rubus idaeus L.) is one of the most important berry crops economically in Finland but the profitability is weakened due to frequent winter injuries and varying yields. Protected berry production has lately become the main cultivation method of raspberries in Europe. Long cane raspberry is a special plant type that has been induced to flower and cold stored to produce a harvest in the year of planting. Specifically designed for protected cropping raspberry long canes have been shown to possess a very high cropping potential. The aim of this study in the first experiment was to examine the effect of growing conditions, primocane and floricane number and storage time on yield of red raspberry long canes. Raspberries were grown in an open field and in a tunnel with varying cane numbers (1 or 2). After cold storage they were forced in a plastic tunnel and new shoots were allowed to grow alongside the floricanes. The canes grown in a tunnel yielded 56 % more compared to those grown outdoors. The plants with two floricanes yielded 39 % more compared to plants with only one floricane but their average berry weight was 0,6 g lower. Presence or absence of primocanes didn’t have an effect on the yield or other growth parameters of the floricanes. In the second experiment plants were grown in an open field and in a tunnel and cold stored for three different periods of 4, 12 or 20 weeks. After storage the plants were forced to flower in a greenhouse. The cropping potential of the plants stored for 20 weeks (977 flowers/plant) was almost three times as high compared to those stored for only 4 weeks (332 flowers/plant). Plants that had been stored for 20 weeks also produced 138 % more laterals that were 14 % longer than plants stored for 4 weeks. Bud break for plants stored for 20 weeks took place 25 days earlier than for those stored for 4 weeks. Carbohydrate content of raspberry cane is related to its ability to produce a harvest. In this experiment the concentration of soluble carbohydrates increased and the concentration of starch decreased during storage. The total carbohydrate content in the whole plant also decreased during storage and it was 12-40 % higher in plants grown in a tunnel compared to the ones grown in an open field. According to this research it is possible to increase raspberry yields with long cane plants. In the two experiments growing conditions and storage time were found to have the biggest influence on cropping potential. The most optimal long cane plant type based on this research would be a plant with two canes that has been grown in a tunnel and cold-stored 20 weeks at the minimum.
  • Juárez Gámez, Donald (2012)
    Cocoa (Theobroma cacao L.) is an economically important crop for Nicaragua. It represents a secure source of income for the farmers basically because of the high demand in the international market for the chocolate industry. In Nicaragua cocoa production is carried out on small scale farms and the most critical point in the production system is the low propagation rate obtained by asexual propagation methods. The present study aimed to evaluate cocoa propagation by somatic embryogenesis following the protocol developed at the Pennsylvania State University and to validate a reliable protocol for its conservation for long term. Induction of primary somatic embryos was carried out from petals and staminodes of unopened flower buds of the genotype Scavina-6 of two physiological ages. The best frequency on primary embryogenic callus growth was obtained by 1-2 week old petals. Secondary embryo development was done from cotyledons of primary somatic embryos of the clones LCTEEN 28/S-1 and PA 169. It was determined after incubation of the embryos in four different periods in secondary callus growth (SCG) medium. The highest number of embryogenic explants was obtained for the clone PA 169 after 8 weeks in SCG medium and 6 weeks in embryo development (ED) medium whereas, the best embryo production ratio during the time in ED medium was scored by explants of LCTEEN 28/S-1 incubated twice in SCG medium. Long term conservation was evaluated by incubating immature embryos of both clones LCTEEN 28/S-1 and PA 169 in liquid nitrogen. There was not registered survival of the embryos after the freezing treatment. However, most of the non-frozen embryos could survive and regenerate from the alginate capsules suggesting that the survival was not threatened by the sucrose concentrations used to dehydrate the embryos but most likely by the intracellular ice formation from the water content that remain in the cell after the dehydration period.
  • Xie, Long (2014)
    Glomus intraradices and Bacillus amyloliquefaciens are two commercially used plant growth promoting micro-organisms. They associate with plant roots to facilitate host plants to absorb nutrients, induce resistance against pathogens and pests, and regulate growth through phytohormones. Growth conditions for plants on green roofs are often unfavorable. In order to test whether growth and development of green roof plants could be enhanced via improving the microbial interface, G. intraradices and B. amyloliquefaciens were inoculated on experimental plots on a green roof in the summer of 2012. The experimental plots were marked as R (inoculated with B. amyloliquefaciens from Rhizocell), M (inoculated with G. intraradices from MYC4000), and C (control). The green roof was made of sedum-herb-grass mats. The plants included e.g. stonecrops, bluegrasses, yellow rockets, white clover, mullein, pennycress, and moss. The survival and development of G. intraradices and B. amyloliquefaciens were studied respectively from Poa alpina roots and soils in the summers of 2012 and 2013. G. intraradices was not detected in P alpina roots according to root staining and microscopy. Probable reasons for the lacking of G. intraradices include high phosphorus content in the soils, high soil temperature, and low soil moisture. PCR and qPCR were used to detect Bacillus content in green roof soils. The abundance of B. amyloliquefaciens was related to soil water content and soil temperature. During the last two measurements in 2012, 4 weeks of high moisture content in the soil resulted in large increase of B. amyloliquefaciens content in both M and R groups, but then decreased substantially due to drought and heat in 2013. In 2013, Only R group increased from the third to the last measurement, indicating probable resistance of the B. amyloliquefaciens strain from Rhizocell additive. The synergistic effect of B. amyloliquefaciens and G. intraradices might be responsible for the thousand-fold increase of Bacillus content in M group in 2012.
  • Jiang, Panpan (2013)
    Strawberries are perennial, flowering plants of genus Fragaria, in the family Rosaceae. Woodland Strawberry (wild F.vesca) is the most widely distributed natural species in the northern hemisphere and a new promising model plant for the study of flowering in perennial plants. Classified as a seasonal flowering short day (SD) plant, wild F.vesca initiates flowering in the autumn, flowers in spring and forms fruits in summer followed by a vegetative growth phase until the next autumn. The perpetual flowering genotype Hawaii-4 flowers continuously throughout the season. Flowering is regulated by ambient signals such as photoperiod and temperature. The photoperiod x temperature interaction was found to play a vital role in flowering initiation in Fragaria. SD F.vesca can behave as a day-neutral, short day plant or non-flowering plant depending on different ambient temperature. Flower initiation takes place regardless of photoperiod when F.vesca is put at 9°C, but only flower under SD at 15°C and no flowering is observed when the ambient temperature is higher than 21°C. The experiment was designed to observe flower induction and explore the role of few flowering genes in the temperature regulation of flowering at long day (LD) condition. The expression of key flowering genes FT, SOC1 and TFL1 were analyzed in wild F.vesca and transgenic lines in F.vesca background. The results showed low temperature (11°C) promotes flowering in SD F.vesca. FT was down-regulated by 11°C and negatively correlated with flowering in F.vesca, in contrast to findings in other SD plants. SOC1 may act downstream of FT, it represses flowering in SD F.vesc and may affect vegetative growth by interacting with GA pathway. Although FT functions as an integrator gene in flowering, there may be an FT-independent pathway in SD F.vesca. SOC1 integrates signals from different pathways; it might be the candidate gene mediating signals from the thermosensary pathway. TFL1, identified as SEASONAL FLOWERING LOCUS (SFL) in SD F.vesca, represses flowering and is regulated by temperature.
  • Binte Mostafiz, Suraiya (2014)
    Plant production in soilless systems is attracting increased interest day by day. The major reason for these interest is the fact that soilless medium can help to eliminate soil-borne diseases and give an understanding of plant nutritional requirements. The aim of this thesis is to evaluate the suitability of chemically and physically modified wood shavings as growing media for horticultural crop production. Five different wood shavings derived from Scots pine trees, namely untreated wood, heat treated wood, organic acid treated wood, Q-Treat, Q-Treat and organic acid treated wood, along with mixtures of peat and Q-Treat as 50/50 v/v (P50Q50), 25/75 (v/v) (P25Q75) and peat (control ) were used. In order to assess the characteristics of the growing media phytotoxicity, pH, water holding capacity, N immobilization, EC, water content of the substrates were analysed. Plant performances on the substrates was evaluated by observing the vegetative and generative growth of Hosta ‘Golden Tiara’ and strawberry ‘Elsanta’ plants. Q-Treat, organic acid treated wood and P50Q50 showed a high water holding capacity. No nitrogen immobilization was observed in Q-Treat. At the same time, EC and water content of the substrates were favourable for both Hosta ‘Golden Tiara’ and strawberry production. Hosta ‘Golden Tiara’ plants grew satisfactorily on all the substrates but the visual quality of the plants was unacceptable on untreated wood. For strawberry, vegetative growth was strong on peat and P50Q50. Least runners were formed on P25Q75 and all of the wood substrates. However, the yield from strawberries was highest on peat and P25Q75. The quality of strawberry fruits on wood substrates was equal to that on peat. In conclusion, based on the results obtained in this experiment, 50% of peat may be replaced by 50% Q-Treat in soilless cultivation for Hosta ‘Golden Tiara’ and 75% of peat may be replaced by Q-Treat in soilless strawberry production.