Browsing by Subject "kukinta"

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  • Luomajoki, Alpo (The Society of Forestry in Finland - The Finnish Forest Research Institute, 1993)
    Anthesis was studied at the canopy level in 10 Norway spruce stands from 9 localities in Finland from 1963 to 1974. Distributions of pollen catches were compared to the normal Gaussian distribution. The basis for the timing studies was the 50 per cent point of the anthesis-fitted normal distribution. Development up to this point was given in calendar days, in degree days (>5 °C) and in period units. The count of each parameter began on March 19 (included). Male flowering in Norway spruce stands was found to have more annual variation in quantity than in Scots pine stands studied earlier. Anthesis in spruce in northern Finland occurred at a later date than in the south. The heat sums needed for anthesis varied latitudinally less in spruce than in pine. The variation of pollen catches in spruce increased towards north-west as in the case of Scots pine. In the unprocessed data, calendar days were found to be the most accurate forecast of anthesis in Norway spruce both for a single year and for the majority of cases of stand averages over several years. Locally, the period unit could be a more accurate parameter for the stand average. However, on a calendar day basis, when annual deviations between expected and measured heat sums were converted to days, period units were narrowly superior to days. The geographical correlations respect to timing of flowering, calculated against distances measured along simulated post-glacial migration routes, were stronger than purely latitudinal correlations. Effects of the reinvasion of Norway spruce into Finland are thus still visible in spruce populations just as they were in Scots pine populations. The proportion of the average annual heat sum needed for spruce anthesis grew rapidly north of a latitude of ca. 63° and the heat sum needed for anthesis decreased only slighty towards the timberline. In light of flowering phenology, it seems probable that the northwesterly third of Finnish Norway spruce populations are incompletely adapted to the prevailing cold climate. A moderate warming of the climate would therefore be beneficial for Norway spruce. This accords roughly with the adaptive situation in Scots pine.
  • Luomajoki, Alpo (The Society of Forestry in Finland - The Finnish Forest Research Institute, 1993)
    Timing of anthesis in 21 Scots pine stands from 14 localities in Finland was studied at the canopy level from 1963 to 1974. Distributions of pollen catches were compared to the normal Gaussian distribution. The basis for the timing studies was the 50 per cent point of the anthesis-fitted normal distribution. Development up to this point was characterized in calendar days, in degree days (>5 °C) and in period units. The count of each unit began on March 19 (included). The period unit was found to be the most accurate delineator of development both in a single year and also in the majority of cases as stand averages over several years. Locally, calendar days were a more accurate parameter for stand average. Anthesis in northern Finland occurred at a later date than in the south as was expected, but at a lower heat sum. The variation in the timing of anthesis and the variation of pollen catches increased northwards. The geographical correlations calculated against distances measured along simulated post-glacial migration routes were stronger than purely latitudinal correlations. Effects of the reinvasion of Scots pine into Finland are thus still visible in pine populations. The proportion of the average annual heat sum needed for anthesis grew rapidly above a latitude of 63° even though the heat sum needed for anthesis decreased towards the timberline. In light of flowering phenology it seems probable that the northern populations of Scots pine in Finland have still not completely adapted to the prevailing cold climate at these latitudes. A moderate warming of the climate would therefore be beneficial for Scots pine.
  • Saarsalmi, Anna; Savonen, Eira-Maija; Nikkanen, Teijo; Lipas, Erkki; Mikola, Jouni (The Finnish Society of Forest Science and The Finnish Forest Research Institute, 1994)
    The aim of the study was to obtain the information needed in preparing more precise fertilization recommendations for seed orchards. The fertilization requirement was estimated on the basis of soil and needle analyses, and by investigating the effects of different fertilization treatments on male and female flowering, the size of the seed crop and seed quality. The study was carried out in two Scots pine (Pinus sylvestris L.) seed orchards in southern Finland, one of which was established on forest soil in 1971 and 1972, and the other on a peat field in 1974. 10 clones and 39 grafts from each clone were selected randomly from both orchards in autumn 1985. There were 13 treatments per clone, with three replications. The treatments consisted of N, P and K in various combinations, micronutrients, wood ash and grass control. The orchards were fertilized in spring 1986 and the seed crops collected in 1985–1990. There were statistically significant differences between the clones in both orchards as regards amount of flowers, size of the seed crop and seed quality. The annual variation in flowering and the size of the seed crop were also large. In general, the seeds from cones collected in October matured well and their germination percentage was high. The effects of fertilization on flowering, the size of the seed crop and seed quality were small. It would appear that the size of the crop can be affected to a much greater extent by favouring clones with a high seed-producing capacity than through fertilization. Fertilization is unnecessary if the nutrient status of the soil is satisfactory.
  • Luukkanen, Olavi (Suomen metsätieteellinen seura, 1981)
  • Kraft, Kaisa; Seppälä, Jukka; Hällfors, Heidi; Suikkanen, Sanna; Ylöstalo, Pasi; Anglès, Sílvia; Kielosto, Sami; Kuosa, Harri; Laakso, Lauri; Honkanen, Martti; Lehtinen, Sirpa; Oja, Johanna; Tamminen, Timo (Frontiers Media S.A., 2021)
    Frontiers in Marine Science 8: 594144
    Cyanobacteria are an important part of phytoplankton communities, however, they are also known for forming massive blooms with potentially deleterious effects on recreational use, human and animal health, and ecosystem functioning. Emerging high-frequency imaging flow cytometry applications, such as Imaging FlowCytobot (IFCB), are crucial in furthering our understanding of the factors driving bloom dynamics, since these applications provide community composition information at frequencies impossible to attain using conventional monitoring methods. However, the proof of applicability of automated imaging applications for studying dynamics of filamentous cyanobacteria is still scarce. In this study we present the first results of IFCB applied to a Baltic Sea cyanobacterial bloom community using a continuous flow-through setup. Our main aim was to demonstrate the pros and cons of the IFCB in identifying filamentous cyanobacterial taxa and in estimating their biomass. Selected environmental parameters (water temperature, wind speed and salinity) were included, in order to demonstrate the dynamics of the system the cyanobacteria occur in and the possibilities for analyzing high-frequency phytoplankton observations against changes in the environment. In order to compare the IFCB results with conventional monitoring methods, filamentous cyanobacteria were enumerated from water samples using light microscopical analysis. Two common bloom forming filamentous cyanobacteria in the Baltic Sea, Aphanizomenon flosaquae and Dolichospermum spp. dominated the bloom, followed by an increase in Oscillatoriales abundance. The IFCB results compared well with the results of the light microscopical analysis, especially in the case of Dolichospermum. Aphanizomenon biomass varied slightly between the methods and the Oscillatoriales results deviated the most. Bloom formation was initiated as water temperature increased to over 15°C and terminated as the wind speed increased, dispersing the bloom. Community shifts were closely related to movements of the water mass. We demonstrate how using a high-frequency imaging flow cytometry application can help understand the development of cyanobacteria summer blooms.
  • Luukkanen, Olavi; Johansson, Stig (Suomen metsätieteellinen seura, 1980)
  • Tormilainen, Mikko (Suomen metsätieteellinen seura, 1972)
  • Lähde, Erkki; Pahkala, Katri (Suomen metsätieteellinen seura, 1974)
  • Sairasalo, Maria (Helsingin yliopisto, 2019)
    Research has shown that the temperature sum or the average of daily mean temperature, together with the photoperiod and genotype, determines the progress of faba bean towards flowering. However, other environmental factors such as photosynthetically active radiation (PAR) and humidity conditions (Sielianinow´s hydrothermal index K) have been found to have a secondary effect on the progress towards flowering. The timing of the development stages of faba bean growth is of great importance for its regional adaptation and the profitability of its cultivation in new and changing environments. Progress towards flowering and the environmental conditions during flowering strongly affect the yield of different cultivars. Identifying the environmental factors affecting initiation and induction of flowering enables the breeding of new, more sustainable cultivars of faba bean. Negative effects of stress factors to yield can be avoided using earlier flowering cultivars in cultivation. Changing climatic conditions are leading to long periods of dry and warm weather in Finland, the effect of which is particularly pronounced during flowering. The stage of flowering has been found to be the most sensitive stage of the development of faba bean, during which the amount and quality of the crop yield is determined. The aim of this study was to validate the functionality and suitability of the improved model for predicting the progress towards flowering in field conditions. The significance of PAR, K-index, the temperature mean and photoperiod was tested in the model predicting flowering, were the observations of flowering were from two growing seasons, 2016 and 2017, using 20 cultivars of faba bean. The impacts of these environmental factors on the model were also tested with broader observation data from six growing seasons: 2009 to 2012 together with 2016 to 2017. The best model was obtained with the combination of all parameters with the highest value of R2 (R2v2=0.999, R6v2= 0.964). In the model containing only photoperiod and temperature mean, values for R2 were too low. The parameters of PAR and K-index significantly (R2>0.90) increased the value of R2. When tested alone, PAR explained over 90 % of the flowering. However, the photoperiod and the temperature mean played an important role in the development and flowering and they are known to be critical for the induction of flowering of certain cultivars. With six years of observations, the coefficients for temperature mean in the model were negligible (p >0.05). Significant parameters were photoperiod, K-index and PAR. The cultivar ‘Kontu’ started to flower earlier than other cultivars and it had greatest variation between predicted and observed value in the model. Therefore, adding it to the function as extra parameter was important to bring its values closer to regression line and to improve the overall value of R2. The conditions in greenhouse are usually adjusted to the optimum for the plant, when normally varying humidity conditions are ignored. Effects of photoperiod and PAR on the development of faba bean cannot be distinguished in controlled light conditions. Field experiments lasting several growing seasons are required to be able to distinguish their effects. The model for predicting the progress towards flowering could be used to identify different qualities of various cultivars. The parameters in this model worked well in prediction of flower induction of faba bean in Finland.
  • Pukkala, Timo (Suomen metsätieteellinen seura, 1987)
  • Heino, Fanni (Helsingin yliopisto, 2015)
    Finding a hybrid breeding method for turnip rape (Brassica rapa L. ssp. oleifera (DC.) Metzg.) would allow the breeding of semi-dwarf cultivars that usually tend to lodge less and have a higher yield index. Some dwarf genes can shorten not only stem but also root which is not optimal for water and nutrient uptake. The effects of the dwarf gene BREIZH (Bzh) on turnip rape have not been reported earlier. The aim of this research is to investigate the effects of the Bzh gene on the structure of shoot and root of turnip rape and estimate if Bzh could be used in breeding semi-dwarf turnip rape cultivars. The research was organized in Viikki Greenhouse in Helsinki, and four turnip rape F2-lines were used in research. The progeny was presumed to distribute according to Bzh gene 1 : 2 : 1 (dwarfs : semi-dwarfs : wild types). Also field experiment was organized but it had to be discarded because of damages caused by geese. In the greenhouse the genotype was estimated twice according to length of hypocotyl. The starting and finishing time of flowering was recorded. After flowering the stems were cut from root and the height of stem and also the heights to the lowest and the highest branches were measured. The number of branches and nodes were counted as well. The roots were washed and the length of the main root and the dry weight of the root were measured. The correctness of the genotype estimate that was formatted by estimated hypocotyl length and measured stem length was evaluated by High Resolution Melting analysis. The control samples were sequenced in order to get information about the base sequence in mutation area. The Bzh gene shortened the stem by shortening the internode length. Also height to the lowest branch was significantly lower in semi-dwarfs. Usually these features together cause the better lodging resistance of the semi-dwarf cultivar. The gene also increased the amount of branches but didn’t affect the amount of nodes. Bzh didn’t affect the length of the main root but slightly decreased the dry weight of the root. There was a large variety in the appearances of the roots. Bzh also delayed flowering and decreased duration of it by one day. HRM analysis is a quick method for determining the Bzh genotype in turnip rape. Estimating genotype by phenotype of the plant is only directional. The Bzh mutation is a mutation of two single nucleotides (G-->A) and it is similar on both turnip rape and oilseed rape. According to the effects on structure, the Bzh gene seems to be suitable for breeding semi-dwarf turnip rape cultivars in future.
  • Maula, Sanna (Helsingin yliopisto, 2018)
    Buckwheat yield vary greatly between years, and in some years the seed production fails completely. In general, low yield is a problem in buckwheat farming. Only 10-15 % of buckwheat flowers will develop into seeds, regardless of pollination. The reason for this is thought to be the sterilization of the pistils in the flowers, which could be caused by insufficient growth resources during flowering and seed maturing. In addition, the degree of seed filling in the nutlets can be so low that only half of the gross weight of nutlet yield is suitable for nutrition. Buckwheat has been found to be particularly susceptible to insufficient levels of magnesium during flowering, and it also contain more phosphorus than magnesium. However, buckwheat is considered an unambitious plant in terms of fertilization, and its need for micronutrient fertilization has not been studied intensively. However, magnesium fertilization has been shown to increase yield in some experiments. This study was conducted as a foliar fertilization trial in Tuusula. The goal was to determine the effects of magnesium foliar fertilization on the flowering and yield in buckwheat. The treatments included control, water spraying and two magnesium fertilizations treatments. Magnesium fertilization treatment was applied either at the first stages of flowering orat the first stages of flowering and also during full flowering. Magnesium was applied 1,2 kg per hectare. The effects of magnesium fertilization were not statistically significant to the development rate, height of stem, length of flowering, flower biomass, final nutlet yield, 1000 seed weight, number of hollow nutlets, the percentage of nutlet hull or hectolitre weight. There were indications that magnesium has potential to increase nutlet yield. Flowering lasted 12 weeks, which is a normal length for buckwheat in Finland. Nutlet yield was 878-1236 kg per hectare, which is an average yield for buckwheat in Finland. The nutlets had light weight. The amount of magnesium fertilization may have been too low to have an effect on the development and yield of the trial. The trial field suffered from excess moisture in particular during ripening, which has been found to have an adverse effect on the growth and yield of buckwheat. The study was conducted during one growth season and it is presumable that the heavy rains during the season and the excessive moisture in the trial field had an effect on the results of the study. A second year of field experiments in required to verify the effects of magnesium fertilization on the yield formation of buckwheat.
  • Richterich, Daniel (Helsingin yliopisto, 2014)
    The strawberry is the most widely cultivated berry in Finland. Producers in Finland grow short-day varieties of strawberry with the mid-season variety Polka being the most popular. Very little breeding is done in Finland and the characteristics of foreign varieties are not tailored to the local growing con-ditions here. Given these circumstances, it is a challenge to choose varieties for production that will flourish in Finland. The calculated and polyvalent use of different strawberry varieties could prolong the growing season and help stimulate productivity and growth in this area of horticulture. The aim of this research is to develop a rapid test for identifying strawberry varieties whose flowering phenology will suit production in Finland. In this research we aimed to develop a test based on short-day treatment to compare the earliness of different varieties. The influence of short-day treatment on flowering and growth was studied in seven short-day strawberry varieties in a greenhouse experiment. Beside the influence of the treatment on the timing of flowering we tested the relationship between earliness and changes in the vegetative growth of our varieties. The experimental conditions comprised two day-length treatments and one control. The first short-day-treatment lasted six weeks with a photoperiod of 12 h. The second short-day treatment, a so called “step” treatment, lasted nine weeks. The day-length in the step treatment was shortened every three weeks, starting at 16 h, and then dropping to 14 h and 12 h. In the long-day control the day-length was 18 h. The greenhouse temperature was a constant 18 ºC in all treatments. We tested early varieties Honeoye, Elianny, Flair and Wendy, the mid-season variety Polka and late varieties Bounty and Florence. The plants in our experiment didn’t develop as we expected. The early variety Wendy was amongst the first to flower, and the late variety Florence amongst the last in both treatments. The earliness of the other varieties we tested was not consistent with how these varieties flower in the open field. Furthermore, the relative vegetative growth couldn’t be associated with the flowering time. In both short-day treatments the growth of the runners stopped first in the early varieties Wendy, Honeoye and Flair. In the remaining varieties, the growth of the runners was unrelated to the expected earliness of the flowering. The length of the petiole was responsive to the first short-day treatment, but growth of the runners and the petioles did not correlate with early flowering. However slow growth of the late variety, Florence, suggests that the growth rate may be connected with the flower phenology in the variety. Finally, Polka was the variety to exhibit most crown branching in this experiment. According to the results of this experiment the earliness of short-day strawberry varieties cannot be determined with just an experimental short-day treatment. The other growing conditions in the green-house are also likely to affect the response of the tested varieties, potentially masking or interacting with the day-length effect. In addition to day-length, the response of the varieties to the temperature, and to the combined effect of day-length and temperature, should be taken into account. A suitable greenhouse test could comprise day-length and temperature treatments or the combination of both of them. Alternatively flower induction could be performed in the field and subsequently plants could be forced in the greenhouse.
  • Koski, Veikko (Suomen metsätieteellinen seura, 1980)
  • Brando, Vittorio E.; Sammartino, Michela; Colella, Simone; Bracaglia, Marco; Di Cicco, Annalisa; D’Alimonte, Davide; Kajiyama, Tamito; Kaitala, Seppo; Attila, Jenni (MDPI, 2021)
    Remote Sensing 2021, 13(16), 3071
    A relevant indicator for the eutrophication status in the Baltic Sea is the Chlorophyll-a concentration (Chl-a). Alas, ocean color remote sensing applications to estimate Chl-a in this brackish basin, characterized by large gradients in salinity and dissolved organic matter, are hampered by its optical complexity and atmospheric correction limits. This study presents Chl-a retrieval improvements for a fully reprocessed multi-sensor time series of remote-sensing reflectances (Rrs) at ~1 km spatial resolution for the Baltic Sea. A new ensemble scheme based on multilayer perceptron neural net (MLP) bio-optical algorithms has been implemented to this end. The study documents that this approach outperforms band-ratio algorithms when compared to in situ datasets, reducing the gross overestimates of Chl-a observed in the literature for this basin. The Rrs and Chl-a time series were then exploited for eutrophication monitoring, providing a quantitative description of spring and summer phytoplankton blooms in the Baltic Sea over 1998–2019. The analysis of the phytoplankton dynamics enabled the identification of the latitudinal variations in the spring bloom phenology across the basin, the early blooming in spring in the last two decades, and the description of the spatiotemporal coverage of summer cyanobacterial blooms in the central and southern Baltic Sea.
  • Kymäläinen, Sonja (Helsingfors universitet, 2016)
    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.
  • Töttölä, Henni (Helsingin yliopisto, 2018)
    Timoteitä (Phleum pratense L.) viljellään Suomessa karjalle rehuksi. Sen kasvuston rakenne vaikuttaa satoon ja sadon ominaisuuksiin. Typpilannoituksen, vernalisaation ja genotyypin kaikkia vaikutuksia näihin ominaisuuksiin ei vielä tiedetä tarkkaan. Tietoa tarvitaan uusien lajikkeiden typpilannoitussuositusten kehittämiseen sekä avuksi timotein lajikejalostuksessa sopeuduttaessa ilmastonmuutokseen ja maataloustuotannon kestävään tehostamiseen. Tämän tutkimuksen tavoitteena oli selvittää miten typpilannoitus, vernalisaatio ja kasvin perimä vaikuttavat timotein kasvustorakenteeseen ja miten typpi vaikuttaa vernlaisaatio geeneihin ja kukintaan. Kokeessa oli mukana kaksi timotein genotyyppiä, eteläinen (BorE) ja pohjoinen (BorP), jotka eroavat toisistaan vernalisaatiovaatimukseltaan. Typpitasoja oli kolme, jotka vastasivat peltolannoituksen tasoja 11,6 kg N/ha (N1), 278,3 kg N/ha (N2) ja 545,0 kg N/ha (N3). Kasvit joko vernalisoitiin 10 viikon ajan tai niitä ei vernalisoitu ennen siirtoa kasvihuoneelle pitkään päivään. Kasveista mitattiin viikottain korren pituus, versojen lukumäärä ja lehtien lukumäärä, sekä kokeen lopussa kuiva-aineen kertyminen sekä versotyyppien lukumäärä (GEN, ELONG, VEG). Kasveista kerättiin näytteitä ennen pitkään päivään tai vernalisaatioon siirtämistä sekä 1-4 vk kasvihuoneelle siirron jälkeen RNA näytteet, joista analysoitiin PpVRN1 ja PpVRN3 geenien ilmeneminen qPCR analyysillä. Typpilannoitus vaikutti tilastollisesti merkittävästi kaikkiin mitattuihin tekijöihin kasvustorakenteessa. Typpi lisäsi erityisesti versojen lukumäärää ja se alensi tai viivästytti erityisesti PpVRN3 geenin ilmenemistä. Vernalisoimattomassa BorE kasveissa typpi lisäsi myös GEN versojen lukumäärää. Typellä oli kaiken kaikkiaan tilastollisesti merkittävä vaikutus VRN geenien ilmenemiseen. Lisäksi genotyyppi vaikutti kasvustorakenteen siten, että BorE olivat keskimäärin korkeampia. Timotein genotyyppi vaikutti typen vasteeseen ainoastaan korsijakauman kautta. Typpilannoituksella ja sen määrällä havaittiin olevan vaikutusta timotein kasvustorakenteeseen, kukkivien versojen lukumäärään sekä vernalisaatiogeenien ilmenemiseen. Typen vaikutukset eivät kuitenkaan olleet yksiselitteisiä vaan yhdysvaikutuksia esiintyi runsaasti. Typen vaikutukset kukintaan oli selkeämpi BorE kasveissa, mikä voi viitata siihen, että vernalisaatiolla ja sen vaatimuksella voi olla merkitystä genotyypin typpivasteeseen.