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Browsing by study line "Kasvintuotantotieteet"

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  • Määttä, Sara (2023)
    Tutkimuksen tavoitteena oli selvittää, onko aluskasvillisuuden monimuotoisuudella vaikutusta virustautien esiintyvyyteen ohran viljelyssä ja mikä on monimuotoisuusasteen vaikutus kirvojen esiintyvyyteen. Ohranäytteitä oli vuosilta 2021 ja 2022 sekä molempien vuosien näytteet olivat kerätty Viikin koe- ja tutkimustilalta. Näytteissä esiintyvät virukset selvitettiin eristämällä ohranäytteistä sRNAt ja lähettämällä ne sekvensoitaviksi. Aluskasvillisuuden vaikutusta kirvojen määrään selvitettiin käyttämällä imurinäytteitä kirvoista ja tarkastelemalla kirvojen määrän ja monimuotoisuusasteiden suhdetta. Vuoden 2021 näytteissä esiintyi viruksia huomattavasti enemmän kuin vuoden 2022 näytteissä. Syitä tälle erolle ei pystytty tarkasti sanomaan, mutta mahdollisia eroon vaikuttavia tekijöitä on voinut olla näytteiden keräysajankohtien erot, sääolosuhteet tai muut ympäristölliset tekijät. Monimuotoisuusasteiden ja virusten välillä ei pystytty muodostamaan mielekästä vertailua. Monimuotoisuusasteiden välillä ei huomattu kirvojen esiintyvyydessä tilastollisesti merkitsevää eroa, mutta eri näytteiden keräys ajankohtien välillä oli huomattavissa eroja kirvojen esiintyvyyden ja monimuotoisuusasteiden välisten suhteiden regressiosuorissa. Ohranäytteissä esiintyvät virukset pystyttiin menestyksekkäästi selvittämään sRNA:n eristyksen kautta. Imurinäytteet osoittautuivat toimivaksi tavaksi selvittää kirvojen esiintyvyyttä, mutta luotettavien tulosten saavuttamiseksi näytteitä olisi tullut kerätä useammalta vuodelta. Vuoden 2022 näytteiden huomattavasti alhaisempi virusten esiintyvyys vaikeutti myös osaltaan mielekkäiden vertailujen ja luotettavien tulosten aikaansaamiseen. Lopulta aluskasvillisuuden monimuotoisuuden vaikutusta virustautien esiintyvyyteen ohran viljelyssä ei pystytty määrittämään puutteellisen datan vuoksi.
  • Pärssinen, Jonna (2022)
    This study investigated the frost hardiness of cranberry (Vaccinium macrocarpon Ait.) in four cultivars (’Early Black’, ’Howes’, ’Pilgrim’ and ’Stevens’), focusing especially on the frost hardiness of roots in soilless cultivation. Plants for the study were forced in a greenhouse from cuttings of mother plants. The cuttings were rooted in pots diameter of 10 cm x 10 cm in forest peat. Plants were set to grow in the high tunnel over the growing season. Two experiments were conducted during winter 2020–2021. In the experiments, whole plants with pots were exposed to freezing treatments in a controlled freeze chamber at the temperatures of -10, -15, -20 and -30 °C. Control plants were exposed to cooling at +2 °C for an equal time. In the first experiment, plants were exposed to freezing treatment in November straight from the high tunnel. The second experiment took place in January, and plants were overwintered outside until the experiment. After the freezing treatment one upright in each plant was cut, set in a glass tube containing distilled water, and forced in the greenhouse for 14 days. The vitality of the buds, leafs and stems in the cuttings was observed with a stereomicroscope. After the freezing treatment the vegetative growth of the plants grown in pots was cut off exluding the main shoot, which was cut 5 cm above the soil surface. Thereafter plants were forced in the greenhouse over 10 weeks (the light period of 18/6 h, temperature +20 °C). The vitality of the roots was determined by measuring the amount of the new vegetative growth. All the plants tolerated -10 ° C freeze in November and -15 ° C in January, respectively without injury. Some new growth was observed in plants exposed to freezing treatments of -5 ° C below the temperature mentioned above, but frost damage occurred, and the re-growth was decreased compared to control plants. Cultivar Stevens was more tolerant than the others in both experiments conducted. It maintained its growth potential after -15 °C freezing treatment in November, and -20 °C in January respectively. Frost hardiness (LT50) of buds ranged in November from -19 °C to -27 °C. In January ’Stevens’ buds had the highest frost hardiness (LT50 =-36 °C) and ’Pilgrim’ buds had the lowest (LT50 =-27 °C). The environmental conditions throughout the whole growing season may affect frost hardiness, thus, this experiment should be repeated for verifying the results obtained. Also the potential impact of dormancy in the experiment conducted in November cannot be ignored.
  • Lemmelä, Henriikka (2023)
    Efforts to cultivate American cranberry (Vaccinium macrocarpon Ait.) across Finland have not been successful. Even Helsinki is located north (60 ºN) as compared to the main production area of cranberry in North American (39-48 ºN), which causes challenges with cold and frost resistance, as well as with overwintering and low heat sum. Recent research has shown that cranberry could possibly survive in the conditions of Southern Finland. Low temperatures around 0 ℃ break endodormancy during winter. The aim of this research was to find out how growing site affects the dormancy release in four cranberry cultivars, and whether inadequate chilling causes ”umbrella bloom” growth, where the plant blooms but does not grow vegetatively. Samples were taken every fourth week during winter and the depth of dormancy was measured by observing the growth of terminal buds in a greenhouse. In addition, the effect of chilling temperature (-3, +2 and +7 ℃) and duration (8, 10 ja 12 wk) of chilling in controlled condition on the growth of terminal buds of cv. Pilgrim were studied. Under natural chilling conditions, the plants which had grown in a high tunnel during the growth season, needed more chilling units (CU) to achieve normal growth (2755 CU) than the open field growth plants (853-1525 CU). The chilling units accumulated every hour when T < +7 ℃. The amount of normally flowering terminal buds increased with increasing chilling duration. Same time, the amount of ”umbrella bloom” flowering decreased, which refers to the role of inadequate chilling in ”umbrella bloom” flowering. When the plants were chilled under controlled conditions (temperatures +7 ja +2 ℃), chilling units were accumulated more efficiently which caused dormancy release earlier than under natural conditions. Chilling under controlled conditions in temperature -3 ℃ is not recommended because the plants dried up too much. In conclusion, natural chilling in Helsinki (60 ºN) is sufficient for breaking dormancy in American cranberry. Recommendations for chilling cranberry under controlled conditions are in temperature of +2 ℃ for 10 weeks.
  • Freudenthal, Ines (2022)
    The objective of the thesis is to review and characterize (i) typical agroforestry systems in the temperate zone, (ii) levels of soil organic carbon (SOC) in agroforestry and control plots, and (iii) identify the conditions under which agroforestry farming is most likely to enhance SOC. A meta-analysis was conducted to investigate the impact of agroforestry farming systems on SOC stocks at soil depths of 0 – 20, 0 – 40 and 0 – 100 cm. Data was collected from 15 published studies and all sites are located in temperate climates. Studies had to report at least measurements on SOC concentration or stock for an agroforestry plot and a control plot (arable land, grassland, forest). Investigated treatment variables were soil depth, agroforestry system type, soil type, tree species and age. The results have shown significantly higher SOC stocks under agroforestry in comparison to controls in all three soil depth datasets. The largest amount of SOC in agroforestry was found in the first 20 cm of topsoil and at a soil depth of 60 – 100 cm. There were no significant differences found between alley cropping, silvopasture and shelterbelt systems. The most popular tree species in temperate agroforestry were Populus spp., M.domestica, Juglans regia and Picea. But no significant differences in C sequestration could be observed between tree species across all datasets. The assumption that systems with older trees have higher stocks of SOC could not be confirmed. Most common soil types of temperate agroforestry systems were Luvisol, Fluvisol and Chernozem. The meta-analysis did not verify results of other studies, which have shown that clay contents in the soil promote C sequestration. The wide variability and diversity of agroforestry systems has shown to be problematic in conducting a meta-analysis, indicated by a high heterogeneity. Furthermore, different types of study designs, lack of standardized sampling procedures and explanatory variables may have influenced the results. However, the study showed that agroforestry can be a promising carbon dioxide (CO2) mitigation option, also for the temperate climate zone.
  • Kopakkala, Topi (2022)
    In order to achieve carbon neutrality and slow down climate change, it is necessary not only to curb greenhouse gas emissions but also to remove carbon from the atmosphere. In agricultural sector, adding biochars to soils has proven to be one of the most effective methods to sequester carbon. Using biochars in urban planting soils could be simple and effective way to create carbon sinks also in urban environment. Wood based biochars are already available in the market and their viability as soil amendment is supported by an extensive body of research. Despite large evidence from agricultural and greenhouse sectors, research focused on biochars in planting soils for urban trees is scarce. To assess and demonstrate viability of biochars as component of urban planting soils, an experiment was established in 2019-2020 in Hyväntoivonpuisto-park in Helsinki. The experiment consists of four tree species and nine different planting soils, seven of which include biochars. Three of the planting soils were structural soils installed below a sealed surface. Tree growth in planting soils was followed and biomass accumulation was estimated with allometric equations. Planting soil nutrient composition was analysed at the time of soil application and nine months later after first growing season. Pyrogenic carbon fractions were analysed by BPCA analysis. Planting soil physical and hydrological properties were analysed by water retention curves with pF range of 0 – 4.2. After two growing seasons, biochars had increased tree growth in two planting soils compared to the control while in other planting soils with biochar, the growth was similar to control. In structural soils biochars had improved growth, but there were no statistically significant pairwise differences between treatments. Biochars increased the macroporosity of planting soils, indicating they could improve aeration and water conductivity in planting soils. Effects to total porosity and water retention capacity were mixed, but highest total porosity and water retention capacity was observed in planting soil with the highest amount of biochar. Planting soil nutrient composition varied a lot due to different raw materials, limiting the possibilities of making mechanistic analysis of effects of biochars. These results indicate that biochars are viable and safe constituent for planting soils which may increase tree growth by improving soil physical properties and improve carbon sinks in urban infrastructure.
  • Heinonen, Petra (2023)
    Securing food production is an important objective, especially as climate change affects production conditions. Good crop yields are part of food security, but disease pressure and abiotic stress factors limit yield potential. Chemical plant protection products, which have traditionally been used in plant protection, pose an environmental risk and efforts are therefore being made to reduce their use and replace them with, for example, biological plant protection products. Biostimulants aim to improve crop yields. The aim of this study was to determine whether biomass products produced in different ways have antifungal or biostimulant effects. Three different concentrations of biomass products were used in the experiments. In screening experiments, the antifungal activity of biomass products was investigated in petri dish experiments to test their effect on the growth of two plant pathogenic fungi, Fusarium graminearum and Rhizoctonia solani. The biostimulant effect was investigated by a germination experiment on barley. In the following experiments, the effect of biomass products was investigated in the model organism Physcomitrium patens moss. P. patens was inoculated with two fungal isolates, Rhizoctonia solani and Sclerotinia sclerotiorum, and treated with biomass products. Biostimulant properties were observed on uninoculated P. patens. In addition, the study examined, whether the gene expressions of P. patens change due to the influence of biomass products using RT-qPCR. In Petri dish experiments, biomass products inhibited the growth of both F. graminearum and R. solani fungi. The highest concentration tested was most effective against fungi. The lowest biomass product concentration tested was most effective in inducing barley growth. Biomass product in combination with S. sclerotiorum infection caused death of P. patens, but the combined effect with R. solani infection induced P. patens growth. Gene expression of the three transcription factors tested and one defense gene changed by the interaction of biomass products and R. solani infection. Based on the results obtained in the study, biomass products have potential to be used in fungal disease control. The use of biomass products as biostimulants also seems promising. A lot of further research on biomass products is needed to understand their effects on different crops and pathogenic fungi.
  • Seppä-Murto, Emilia (2023)
    Puutarhamansikan (Fragaria × ananassa Duch.) kysyntä on Suomessa suurta ja mansikka onkin tärkein Suomessa viljelty marja. Suomen olosuhteissa mansikan satotaso jää kuitenkin suhteellisen matalaksi ja satokausi on yleisesti käytetyillä kausisatoisilla lajikkeilla lyhyt. Jatkuvasatoiset lajikkeet ja tunneliviljely pidentävät mansikan satokautta huomattavasti ja ovatkin tehokas tapa kehittää tuotantoa ja mahdollisesti lisätä viljelyn kannattavuutta. Biologisten kasvunparanteiden, biostimulanttien, käyttöä on ehdotettu osaratkaisuksi mansikan satotasojen nostamiseen. Biostimulantit ovat kasvien kasvuun ja kehitykseen positiivisesti vaikuttavia aineita ja parantavat kasvin sietokykyä erilaisia stressejä vastaan. Tutkimuksen tarkoituksena oli selvittää kahden biostimulanttivalmisteen, Rhizocell (nyk. Lalrise Vita) ja Greenstim (nyk. Lalstim Osmo) vaikutusta jatkuvasatoisen ’Ria’ mansikan kasvuun ja satoon, sekä kasvinterveyteen. Käsittelyitä kokeessa oli neljä: kontrolli, Rhizocell, Greenstim ja Rhizocell+Greenstim. Tutkimus toteutettiin Luonnonvarakeskuksen Piikkiön tutkimuslaitoksella vuoden 2020 kesällä. Rhizocell on hyötymikrobi Bacillus amyloliquefaciens IT45 sisältävä valmiste, joka nestemäisenä liuoksena kasvin juurelle annettuna vaikuttaa kasvin kasvuun juuriston kehittymisen kautta, ja Greenstim suurimmaksi osaksi glysiinibetaiinista koostuva valmiste, joka kasvustoon annettuna lehtiruiskutuksena vaikuttaa kasvin kasvuun etenkin stressiolosuhteissa. Tulosten perusteella valmisteiden käyttö suomalaisittain ajoittain melko kuumissa oloissa kasvaneilla, mutta hyvin hoidetuilla mansikoilla ei tuonut merkittäviä hyötyjä. Biostimulanttivalmisteiden vaikutus mansikan kasvuun ja satoon oli vähäinen, eikä yksikään valmiste selkeästi hyödyttänyt kasvua, sadontuottoa tai kasvinterveyttä. Valmisteiden käyttö saattoi kuitenkin vaikuttaa kasvien stressinsietokykyyn, sillä Rhizocell+Greenstim -käsittely alensi lehtien flavonoli-indeksiä ja Greenstim-käsittely lisäsi puolustusreaktioissa tärkeän kalsiumin kertymistä lehtiin. Huomioitavaa onkin, että tässä tutkimuksessa kasvit eivät olleet altistettuina stressille ja stimulanttien vaikutuksesta stressiolosuhteissa ei voida olla varmoja.
  • Määttänen, Satu (2020)
    Agroforestry, a widespread land-use in tropics and especially in tropical drylands, is gaining increasing attention due its carbon sequestration and storage potential. Majority of African countries acknowledge agroforestry as a national climate change mitigation and adaptation strategy. Despite the large extent of African drylands and the commonness and importance of agroforestry systems to dryland livelihoods, these systems are scarcely studied and research on dryland African agroforestry carbon stocks are few. The aim of the study was to compare carbon stocks of three land-uses: Vitellaria paradoxa dominated parkland (PL), improved agroforestry system (IA) and, as a control, abandoned land (AL), to study carbon allocation between and within the land-uses and to examine the variability of biomass estimates of different allometric equations used in carbon inventory in West African Sahel. Study was conducted in two villages in Yorosso, Southern Mali. Carbon stocks accounted were woody above- and belowground biomass, litter and top-soil organic carbon. Allometric equations and root-to-shoot ratios were used for woody biomass measurement. Comparison of biomass estimations of different allometric equations and root-to-shoot-ratios was conducted by using multiple equations for the dataset. Total system carbon stocks were 24.7 MgC haˉ¹, 29.9 MgC haˉ¹ and 42.2 MgC haˉ¹, for PL, AL and IA, respectively, with statistically significant difference between PL and IA. Top-soil organic carbon (SOC) was important carbon pool, accounting 34.8 % of total system carbon in PL and IA, and 49.6 % in AL. There were no statistically significant differences on the SOC/biomass C ratios between the land-uses. PL had lower SOC stocks than IA or AL, difference being statistically significant. The reason for lower SOC stock of PL could not be explained in this study. IA had larger woody biomass carbon stocks (27.0 MgC haˉ¹) than PL (15.5 MgC haˉ¹ ) and AL (14.4 MgC haˉ¹), but the difference was not statistically significant due to the similar density of large mature trees in all of the land-uses and partly due to the large woody biomass variation within the land-uses. In all of the land-uses, most of biomass carbon was stored in large mature trees and in two species: V. paradoxa and Parkia biglobosa. Large woody individuals had major impact on the land-use level carbon stocks. For carbon conservation, these individuals should be preserved and spared even during land-use change. Despite relatively large density, young trees and shrubs stored diminutive amount of carbon compared to mature trees. As the currently young planted trees in IA will grow and mature in the future, the woody biomass carbon stocks of the system will increase significantly. Lack of regeneration observed in PL threatens the sustainability of the system and its carbon stocks. Future carbon storage potential of AL depends on the regeneration potential of large tree species. Comparison of different allometric equations for tree biomass estimation revealed substantial variation. The choice of allometric equation used affects the obtained results, hampering the comparison of studies using different equations. Commonly used root-to-shoot ratios vary on their estimations, and most probably by underestimating root biomass. There is a clear need for specialised and standard carbon inventory methods for drylands and agroforestry systems.
  • McPartlin, Maria (2020)
    Cellular agriculture is a novel food production technology that utilizes tissue engineering techniques to culture muscle cells to make cultured meat, or microbes and fermenting to create proteins such as casein, albumin and collagen which can be processed to products similar to milk and egg white for example. This thesis aims to explore the challenges that cellular agriculture faces in terms of policy, politics and the society mainly in a Finnish context, but also observing EU regulations. These challenges were investigated by interviewing altogether 15 representatives of stakeholder groups, which are political parties, government administration, organizations of policy executioners, NGO’s, food-tech companies, -funds and research centres. The data from the interviews was transcribed and processed in Atlas.ti-software using the analysis of qualitative content -method. The processed data was then analysed using the analysis of a specialist interview -method. The study revealed that specialists agree that cellular agriculture products will follow EU Novel Food regulations, but that cellular agriculture might have to overcome some regulation-related challenges. Challenges might also arise from markets, consumers and competing with conventionally produced food. Some believed cellular agriculture to have a negative impact on the Finnish society in the form of eroding rural livelihoods, and that the production will be in the hands of large corporations. Many stated that they do not believe cellular agriculture will surpass conventional agriculture, but that it will become just another food innovation. Some believed cellular agriculture offers great possibilities in the form of more sustainable food production. Many of the statements of the interviewees reflected current events already underway in the cellular agriculture and alternative protein field. The challenges cellular agriculture will face are multifaceted, and more information is still needed, especially on the societal effects of cellular agriculture.
  • Shehata, Reham (2022)
    Cell walls (CWs) are the safeguards of plant cells and have a crucial role in controlling cell integrity and plant-environment interactions. Perception of cell wall damage (CWD) results in activation of signaling pathways leading to activation of plant defiance responses. Previous research utilizing murus1 GDP-L-fucose deficient mutant has shown the role of GDP-L-fucose biosynthesis in controlling the structure and integrity of the CWs. Here, we investigated whether phenotypical consequences provoked by the lack of GDP-L-fucose, observed in mutants lacking MURUS1 can be suppressed by blocking signal transduction pathways involving THESEUS1 (THE1) receptor-like kinase or WALL-ASSOCIATED KINASE 2 (WAK2)- MAP KINASE 6 (MPK6) signaling module involved in CWD responses. For this, mur1 the1 and mur1 mpk6 double mutants were generated and analyzed. We found that the phenotypes of double mutants closely resemble that of mur1 mutants, indicating that the morphological consequences of GDP-L-fucose deficiency develop independently of THE1 and MPK6 signaling. Further, we aimed to investigate whether GDP-4-keto-6-deoxymannose-3,5-epimerase-4-reductases GER1 and GER2 controlling the final step of GDP-L-fucose synthesis are functionally redundant. Due to the inability of generating ger1 ger2 double mutants, we have applied the artificial microRNA (amiRNA) strategy to generate ger1 ger2 amiRNA knockdown plants. We found that these knockdown plants exhibit severe developmental growth defects similar to those observed in plants impaired in import of GDP-L-fucose into the Golgi apparatus and these growth defects exceeded those observed in plants lacking MUR1. Therefore, we have concluded that GER1 and GER2 are functionally redundant.
  • Valdebenito Alamar, Nerea (2021)
    Despite their immobile nature, their ability for adaptation allows plants to face harmful conditions from the environment to successfully survive and reproduce. Plant cells sense and integrate signals from the environment and activate response mechanisms. Participants in these mechanisms are the receptor-like protein kinases (RLKs) and a subgroup of RLKs, the cysteine-rich receptor-like kinases (CRKs). Members of this family have been associated with functions related to environmental stress responses in plants. CRK2 is one interesting member of the CRK clade of RLKs. While roles of CRK2 in the response to biotic and abiotic stimuli have been recently described, many aspects of the diverse functions of CRK2 remain elusive. The reduced size of the crk2 mutant suggests that developmental processes are affected by the absence of the protein. One of the objectives of this work was to analyse potential reasons for the smaller size of crk2. The difference in plant size could be due to a reduced number of cells. Results from the analysis of young cotyledons showed that the smaller plant size is not due to a reduced cell number in leaves when compared to Arabidopsis thaliana (Arabidopsis) ecotype Columbia (Col-0). Another way to understand the processes in which a protein is involved is to target possible interaction partners. Therefore, genotyping and analysis of growth phenotypes of T-DNA insertion mutant lines for candidate interaction partners for CRK2 was performed. The results revealed smaller phenotype for a nitrate transporter (NRT1.7) mutant in fresh weight and rosette area whereas for a protein kinase (QSK1) mutant, higher fresh weight but reduced rosette area was observed compared to Col-0. Generation of constructs for fusion protein expression and purification revealed the possibility of expressing tagged cytoplasmic regions of these proteins for further analysis of protein-protein interaction through kinase assays due to the kinase activity of CRK2. Generation of fluorescent-tagged proteins from the candidate interaction partners allowed for localization studies via confocal microscopy to determine the co-localization to the plasma membrane of these proteins with CRK2, which is located to plasma membrane under standard growth conditions. The co-localization results suggest that the proteins NRT1.7 and QSK1 colocalize with CRK2, which is a step forward in the verification of their possible interaction in planta. The smaller size of the nrt1.7 and qsk1 mutants indicates that the lack of these proteins affects plant development.
  • Hani, Umama (2021)
    To determine the role of metalloprotease EGY1 and hormone signalling pathways in PSII repair cycle, a mutant named white because of early senescence was identified having 4bp deletion in EGY1. To further characterize the growth responses in white mutant, two suppressors (white suppressor 1 and white suppressor 2), mutated in STAY GREEN1 (SGR1) which prevents chlorophyll degradation, restored the normal white phenotype was identified upon suppressor mutant screens. This study investigated the effect of chloroplast translation inhibitors (lincomycin/chloramphenicol) and MV (methyl viologen) on photosynthesis in Arabidopsis thaliana single and double white mutants. Furthermore, a second goal was to verify the correct identification of the mutations in white suppressor 1 and white suppressor 2. Western blotting and pulse amplitude modulated fluorimeter (PAM) was used to quantify the D1 protein (reaction core of PSII) levels and photochemical efficiency (Fv/Fm) respectively. Immunoblotting revealed a pronounced decrease in D1 levels for both white and egy1. PAM results showed a high tolerance of white mutant towards lincomycin/chloramphenicol. The white suppressors complemented the lincomycin/chloramphenicol tolerance of white mutant. The white mutant was highly MV sensitive. This MV response was altered in white double mutants (white ein2-1, white sr1-4D and white rcd1-4), suggesting that hormone signalling was involved in the response to MV. The decreased abundance of D1 in the white mutant suggests a role for EGY1 in PSII assembly and D1 turnover under light stress. In all assays (immunoblotting and PAM), the white mutant and egy1-2 gave the same results, this confirms the correct identification of the white mutant as a new egy1 allele. The successful restoration of lincomycin /chloramphenicol tolerance by white suppressors (S1 and S2), implicates that chlorophyll breakdown impacts on correct photosynthesis function. The suppressors S1 and S2 were transformed with wildtype SGR1, which restored the white mutant phenotype. Thus, the suppressor phenotype was caused by mutations in SGR1.
  • LU, Jinghong (2022)
    Inflorescence meristem development in plants generally falls into two types: one is the indeterminate type when the main axis keep growing and new flowers are initiated on its flank; while the other is the determinate type when the main axis terminates as a flower and growth continues sympodially. The Asteraceae plant family harbors a unique type of inflorescence, called the flower head. It combines up to hundreds of individual florets into a single structure, but its infloresecence meristem has a determinate fate and can only produce a certain number of florets before getting consumed. The genetic regulation of such determinacy has been recently brought into attention in Gerbera hybrida, a model system used for studying inflorescence and flower development in Asteraceae. So far, several genetic regulators have been identified regulating the determinacy of inflorescence meristem in Gerbera. This thesis aims to characterize new Gerbera transgenic lines to study the function of the Gerbera homolog of TERMINAL FLOWER 1 (GhTFL1). In Arabidopsis and other species, TFL1 is known to counteract with the flower meristem identity genes and maintain the indeterminacy of the inflorescence meristem. Previous results by overexpressing GhTFL1 under constitutive 35S promoter in Gerbera convert the determinate fate of inflorescence meristem into indeterminate. To better study the GhTFL1 function, an inducible overexpression system pOpON2-pOp6/LhGR-N was introduced, and the transgenic lines have been made for GhTFL1. In this this thesis, in total of 19 candidate lines were screened with GUS staining assay and RT-PCR. Two promising lines (TR4 and TR7) with strongest responses in GUS staining and high expression of the target gene were identified. Further treatment of dexamethasone was conducted in these two lines to the growing rosette; however, no clear phenotypes was observed in these lines. The treatment results suggested that further optimization should be made, in particular, the timing of treatment shall be the determining factor for a successful treatment.
  • Jamalainen, Janita (2024)
    Climate change is challenging farmers around the world, undermining food security and livelihoods. Smallholder farmers are encountering changing environmental conditions and extreme weather events as a significant negative impact on their livelihoods and food security when the resources needed to adapt are not sufficiently available. Previous studies show that the impacts of climate change are currently most noticeable in the developing countries of the Global South, where local agriculture and smallholder farming still remain an important part of people's livelihoods and local food security. This study focused on the experiences and outcomes of the Building Resilience -tool I (BR-I) for smallholder farmers in 5 different African countries between 2021 and 2022. Through the tool, farmers assessed the impacts of climate change on their livelihoods and their own capacities and needs to adapt to the challenges caused by climate change. The data used in this study consisted of reports filled in when using the tool collecting farmers' responses, and separate feedback on their experiences of using the tool. The results showed that climate change reduced the predictability of environmental conditions and increased the irregularity of the growing seasons. Drought, floods, and storms were the main threats to crops, often leading to yield losses or poor crop quality. Other losses included livelihood-related losses of material assets, for example during floods and storms. Indirect negative impacts of climate change included loss of farmers' livelihoods, increased poverty and reduced local food security and weaker nutritional quality of food. To adapt to climate change impacts, farmers often used more sustainable and higher quality crop varieties and, for example, built more efficient irrigation systems. However, the results showed that to adapt to climate change, farmers need more material and financial resources and research-based knowledge to improve their livelihood activities.
  • Hadid, Feras (2021)
    The growing demand for crop products caused by population growth and climate change encourages plant scientists to investigate sustainable strategies to tackle such problems. Translating the knowledge of plant molecular mechanisms into applicable practices in the field would help in improving the plants' efficiency and productivity. The size of a plant's shoot apical meristem (SAM) is an important factor in biomass production and crop productivity. Besides, understanding the molecular regulation of the shoot apical meristem would help to know more about the 3D growth innovations of different plant families across the kingdom. This thesis aimed to study the regulation mechanisms of the meristem activity in Gerbera, the model organism of the Asteraceae family that has an informative phylogenetic position to understand evolutionary events. The inflorescence of Gerbera is highly resembling clv3 mutants in Arabidopsis. CLV3 peptide is involved in maintaining the meristem activity, these differences between the two species suggested an evolutionary modification for this pathway. GhCLV3-GhWUS signaling components in Gerbera hybrida were identified following bioinformatics approaches. Then sequence comparisons and phylogenetic analyses between Gerbera sequences and other species were performed. The coding sequence of GhCLV1 was cloned to expression vectors. The expression pattern analysis of the receptors was performed by RT-PCR and RNA-seq data. The results suggest that GhCLV1 is an important factor in maintaining the enlarged inflorescence meristem in Gerbera. Also, all the other receptors were expressed at different levels suggesting their contribution in the GhCLV3-GhWUS pathway and inflorescence termination.
  • Michel, Matthieu (2020)
    Hybrid wheat has been the focus of much research for its potential high yield, high protein content and better resistance to biotic and abiotic stresses. Nowadays, only CHA (Chemical Hybridizing Agent) method is used to induce male sterility at a commercial scale. However, this technique is hard to implement on a large production scale and other methods have been investigated for several years. CMS (Cytoplasmic Male Sterility) has been shown to be a promising way to develop hybrid wheat. However, one downside of the technique is the challenging breeding stage step and the associated conversion and restoration process. To fully express the potential gain in yield, the restoration of the cytoplasmic sterility must be complete for the F1 to be fully fertile. In this study, we investigated different methods to assess fertility restoration in nursery and compared the results with the trial notations. The collected data were also used to feed a genomic selection model to predict the behavior of untested hybrids. The results showed a high experimental error of the bagging method originated mostly from human manipulation. The visual scoring showed higher repeatability but was poorly correlated with trial score. A deeper study of the trial scoring revealed an interesting effect coming from the female and an expression of sterility for commercial lines and CHA hybrid checks. Good prediction accuracies were found for genomic selection on both methods, however deeper studies and cross prediction are needed. The multilocation trials remained the best option to score fertility restoration
  • D Samiraja Mudiyanselage Mahagedara, Shiromi Mangala Samiraja (2024)
    Weeds have been identified as a threat to arable crop production because crop-weed competition may result in considerable yield losses. Weeds and crops often possess similar characteristics, making weed control challenging. Chemical weed control may lead to environmental and health issues, as well as troubles in crop production. Nowadays the tendency is towards more sustainable agricultural practices to control weeds including mixed cropping systems. In earlier studies, mixed cropping systems were observed to reduce weed biomass, whereas weed diversity was affected by environmental and temporal factors. The present study was conducted at the Knehtilä organic farm in Hyvinkää to evaluate the competitive ability of mixed cropping systems against weeds. Crop stands were 50:50:50% and 33:33:33% oat, pea, and camelina mixtures, along with 100% oat, 100% pea, and 100% camelina stands. Plant sampling was conducted 24 Days after seeding (DAS), 38 DAS, 52 DAS, 66 DAS, and 97 DAS. Crops and weeds were separated and the number of plants in each species was counted. Weeds at the species level were identified. Dry biomass of crops and weeds was recorded at each sampling time. Weed species richness, Shannon-Weiner diversity index, species evenness, and species dominance were calculated. The most common weed species was Chenopodium album L., while the least common species was Cerastium fontanum Baumg. Crop stands accumulated in weed biomass until 52 DAS, followed by a gradual decline over sampling times. Weed biomass was lower in 50% and 33% mixes than sole crop stands in early growth stages. Significant differences in the Shannon-Weiner diversity index, species richness, evenness, and species dominance were found in crop stands at 24 DAS and 66 DAS. There was a positive correlation between weed evenness and crop biomass. The study proved that mixed crop stands (50% and 33% mixes) have effective weed control ability, indicating low weed biomasses compared to sole cropping systems. Weed diversity indices fluctuated at 24 DAS and 66 DAS, indicating that sampling time influences weed diversity. The positive correlation between weed evenness and crop biomass indicates the impact on species dominance and intraspecific competition. The study suggests that mixed cropping systems are effective at controlling weeds and highlights the importance of understanding temporal dynamics and weed-crop interactions in cropping systems to enhance crop yield. Future research should focus on understanding the fundamental mechanisms behind weed-crop interactions across cropping systems.
  • Qin, Kaiyue Jr (2020)
    Strawberries (Fragaria sp.) are perennial plants that belong to Rosaceae family. According to flowering habit, strawberries are classified as seasonal flowering and perpetual flowering strawberries. Environmental factors regulate flowering in plants. Among them, photoperiod and temperature are two important cues to affect flowering in strawberries. Besides, FT is a general flowering activator in many plant species. This thesis explored the flowering habits and FT expression level of two diploid strawberries F. bucharica and F. nilgerrensis under short and long day at cool temperature at 11 °C. The results were compared with F. vesca which has been studied earlier. After 2, 4 and 6 weeks of cool temperature (11 °C) treatment, all F. vesca and the majority of F. bucharica flowered regardless of photoperiod. As for F. nilgerrensis, there was no floral induction under SD and 20 % flowering rate after 6 weeks of LD treatment. After 4 weeks of the treatment, the expression of FT was down-regulated in F. vesca and F. bucharica compared with control groups under long day at 20 °C. In conclusion, the cool temperature at 11 °C induced flowering both in F. vesca and F. bucharica. The photoperiod affected flowering in F. vesca, while not in F. bucharica. As for F. nilgerrensis, the treatments were not strongly inductive for flowering. It may need more time for floral induction. The FT1 expression was down regulated after 4-week cool temperature treatments in F. vesca and F. bucharica, which was negatively correlated with flower induction. The photoperiod and temperature significantly affect branch crown formation in F. nilgerrensis, while the temperature had significant effects on runner formation and leaf formation in these three species.
  • Huhdanmäki, Tuukka (2021)
    CRISPR-Cas9 is one variant of newly emerging technologies utilizing targeted mutagenesis based on Cas family proteins and guide RNA that enable binding and modifying selected target sequence. The aim of the master’s thesis was to compare different methods of CRISPR-Cas9 induced gene editing in the genus Nicotiana and other secondary protocols necessary to identify successful mutations. PDS1 and PDS2 genes coding phytoene desaturase in plants were selected as target genes as mutant genotype produce visually identifiable photobleaching phenotype. CRISPR-Cas9 ribonucleoprotein complex mediated transformation uses separately produced Cas9 protein and guide RNA that when combined perform transient gene editing in cell. This method was planned to be used but Cas9 protein was challenging to produce in soluble form and final transformation was not achieved. This study suggests that acquiring ready-to-use Cas9 protein might be preferable choice when targeting only few transformations with CRISPR-Cas9 RNP-complex. Agrotransformation is well established method for genus Nicotiana and using Single Transcriptional Unit CRISPR-Cas9 system it is straightforward procedure from plasmid design to transformation. Successfully transformed plants were redeemed from transient agroinfiltration and stable agrotransformation experiments. Off-target mutations are possible and selective outbreeding may be needed. This method lacks the several advantages of CRISPR-Cas9 RNP-complex such as instant gene editing in cell, avoiding RNA interference and transformation over species boundaries, but is simple and functional in genus Nicotiana. Successful mutations were detected using commercial T7E1 and with natural CEL I endonuclease from celery extract. Celery extract can be used as cost-effective alternative to T7E1 for verifying or replicating previously confirmed results.
  • Mosalam, Mohamed (2021)
    The objectives of the study were to assess the efficiency of transient expression of sgRNA/Cas9 construct in Petunia V26, where sgRNA targeted a cytosine deaminase gene (CodA) that converts 5-fluorocytosine into the toxic compound 5-fluorouracil. Disrupting CodA by transient expression of sgRNA/Cas9 introduced a conditional negative selection system that allowed plants with mutated CodA to regenerate on media containing 5-fluorocytosine. The single transcriptional unit vector pMOH2 was designed to carry two amplified sgRNAs guiding Cas9 targeting at HinfI cutting sites. The expression vector was transformed into Petunia V26 using Agrobacterium tumefaciens (pGV2260). Successful mutations were detected on 62.5 mg/L 5-fluorocytosine. Large numbers of in vitro shoots were regenerated from the transformed leaves on a modified MS-media containing 1 mg/L zeatin. The study revealed that transient expression of the sgRNA/Cas9 construct is efficient and can be used to target other genes in Petunia V26. pMOH2 targeted its sites successfully, and proved that CodA can be used as a conditional negative selection marker to detect cells with an edited genome.