Browsing by study line "Kasvintuotantotieteet"

Legume cultivation is of growing interest in Finland, but legume viruses have been mapped and studied relatively little in our country. The changing climate also creates new types of threats to legume production. Studies around the world provide an opportunity to assume that there are still undetected virus species and genera around Finnish legume production that pose a potential threat to legume production in Finland now and in the future. The aim of this study was to map the viruses present in Finnish legumes. Detected legume viruses from wild plants were characterized by deep sequencing and test plants were inoculated for virus detection. In addition, viruses from experimentally cultivated pea samples as well as faba bean, pea and fodder galega samples collected from Helsinki area were studied by deep sequencing. Soybean dwarf virus (SbDV) was detected in a wild plant sample by deep sequencing. The aim was to ensure the first occurrence of SbDV in Finland by PCR and sequencing. Another aim was to sequence the genome of a possible novel closterovirus detected in a wild plant sample. To identify the closterovirus genome, we utilized the deep sequenced information and designed PCR primers tailored to the virus. To detect closterovirus infectivity, pea and soybean samples were experimentally cultured and inoculated with the closterovirus using the original plant sample. The SbDV detected in deep sequencing and possible novel closterovirus allowed the hypothesis that there are viruses present in Finnish legumes that had not been previously detected or studied.

Viime vuosina Suomessa on havaittu tummia, pyöreitä ja pieniä kuoppia varastoidulla perunalla. Kuopat ovat pinnallisia, ja ne voivat olla yhdistyneet suuremmiksi kuopiksi. Perunan kuoppataudiksi kutsuttu oire heikentää varastoidun perunan laatua. Tutkimuksen tavoitteena oli selvittää, mitkä sienipatogeenit aiheuttavat pinnallisia kuoppaoireita perunassa. Kuoppaoireisista perunoista eristetystä DNA:sta tunnistettiin sieniä PCR-menetelmän ja ITS-sekvensoinnin avulla. Perunoista eristettiin myös viljelymenetelmällä sieniä, jotka tunnistettiin samalla tavalla. Tartutuskokeisiin valittiin viisi niistä sieni-isolaateista, jotka oli tunnistettu ITS-sekvenssin perusteella. Tehtiin haavainokulointikoe, jossa terveitä perunoita haavoitettiin ja tartutettiin valituilla sienillä. Tehtiin myös toinen inokulointikoe, jossa haavoittamattomia emoperunoita tartutettiin sienillä. Emoperunoina käytettiin tavallisia ruokaperunoita ja minimukuloita. Perunoiden tuottamia tytärmukuloita tarkasteltiin kuoppaoireiden varalta, ja taimien korkeus ja tytärmukuloiden yhteispaino mitattiin taimettumisen ja sadontuoton analysoimiseksi. Kuoppaoireisista perunoista eristetyt sienet tunnistettiin ITS-sekvensoinnin avulla lajeiksi Fusarium acuminatum, Ilyonectria crassa, Juxtiphoma eupyrena, Plectosphaerella cucumerina ja Plectosphaerella plurivora. Haavainokulointikokeessa käytetyt sienet aiheuttivat tilastollisesti merkitsevät oireet kontrollikäsittelyyn verrattuna ensimmäisessä mittauspisteessä. Haavoittamattomien emoperunoiden tytärmukuloissa ei havaittu kuoppaoireita. Sienet I. crassa, P. cucumerina, P. plurivora ja Ilyonectria-isolaatti LO3 lisäsivät ruokaperunoiden tytärmukulasatoa. Käsittelyillä ei ollut vaikutusta minimukuloiden sadontuottoon. Käsittelyt edistivät ruokaperunoiden taimettumista. Minimukuloiden taimettumista edisti I. crassa-käsittely, ja taimettumista hidasti P. cucumerina-käsittely. Tulosten perusteella voidaan todeta, että F. acuminatum, I. crassa, P. cucumerina ja P. plurivora ovat perunalle patogeenisia sieniä. Sienet voivat myös edistää perunan taimettumista ja sadonmuodostusta perunalajikkeesta riippuen. Kokeissa ei kuitenkaan saatu aikaiseksi samanlaista kuoppaoiretta kuin alkuperäisissä kuoppaoireisissa perunoissa oli havaittavissa, joten lisää tutkimusta tarvitaan osoittamaan, ovatko kyseiset sienet kuoppaoireen aiheuttajia.

Maatalouden vaikutus vesistöjen rehevöitymiseen on ollut pinnalla useita vuosia. Kalkitus on ikivanha metodi, mutta se on pitänyt pintansa maanparannuskeinona erityisesti Suomessa, jossa peltomaat ovat luontaisesti happamia. Kalkituksen päätarkoitus onkin neutraloida peltomaan happamuutta ja näin parantaa ravinteiden saatavuutta sekä vähentää haitallisten aineiden liukoisuutta viljelykasveille, mikä nostaa viljelykasvin satoa. Kuitenkin erityisesti rakennekalkkien on havaittu stabiloivan savimaan rakennetta tehokkaasti, mikä vähentää mahdollisesti pintamaasta eroosion kautta tapahtuvaa fosforikuormitusta vesistöihin. Rakennekalkituksen vaikutuksista viljelykasvien satoihin puuttuu vielä yksityiskohtaista tieteellistä tietoa viljelykasveittain ja maalajeittain erityisesti Suomen olosuhteissa. Esimerkiksi Ruotsissa tehdyissä rakennekalkituskokeissa on saatu ristiriitaisia tuloksia sen vaikutuksista viljelykasveihin eri pelto-olosuhteissa, eri vuosina. Tämän tutkielman tavoitteena oli selvittää eri rakennekalkitustasojen (0, 8 ja 12 Mg ha-1) vaikutusta vehnän Triticum aestivum L. ’Amaretto’ sadonmuodostukseen korkean (pH(H2O)=6,5) ja matalan (pH(H2O=5.2)) lähtö-pH:n omaavilla savipelloilla. Tutkimus toteutettiin peltokokeina kasvukautena 2020 Sokerijuurikkaan Tutkimuskeskuksella, Hevonpäässä, Varsinais-Suomessa. Koeasetelmana oli sovellettu osaruutukoe, jossa pääruudun osatekijä oli pellon pH ja osaruutuina rakennekalkkikäsittely. Rakennekalkkina käytettiin kalsiumoksidia 19,5 %:a sisältävää tuotetta ja se levitettiin syksyllä 2019. Korkean pH:n lohkolle vehnä kylvettiin 1.5.2020 ja matalan pH:n lohkolle se kylvettiin 26.5.2020. Rakennekalkitusta seuraavana vuotena, etenkin alemman pH:n olosuhteissa, rakennekalkitus paransi vehnän satoja vain hyvin suureella 12 Mg ha-1 käsittelyllä. Päinvastoin korkeamman pH:n olosuhteissa rakennekalkitus ei lisännyt vehnän satoa, vaan aiheutti jopa sadon laskua. Jyvien kokonaistypenotto selitti sadon kasvua, sillä se lisääntyi myös erityisesti alhaisen pH:n sekä suurimman kalkkikäsittelyn olosuhteissa. Rakennekalkitus vaikutti myös ravinteiden kuten kaliumin sekä mangaanin pitoisuuksiin lehdissä ja korsissa sekä tähkien magnesiuminpitoisuuteen molemmilla lohkoilla. Toisaalta rakennekalkituksella ei ollut juurikaan vaikutusta satokomponentteihin eikä sadon laatuun. Kesäkuu 2020 oli kuiva ja aikaisemmin kylvetty lohko kärsi todennäköisesti kuivuudesta, mikä vaikutti todennäköisesti satotuloksiin etenkin korkeamman lähtö-pH:n omaavalla lohkolla, joka kylvettiin aikaisemmin. Tulosten perusteella ei voida tehdä vielä laajempia johtopäätöksiä rakennekalkin vaikutuksista vehnän satoon, vaan tarvitaan myös pitkän aikavälin tutkimusta sekä liittyen satoon, että maaperän ominaisuuksiin.

Plant production and especially food production faces constantly challenges due to plant pathogens. Plant pathogens, such as different kinds of pathogenic fungi, are controlled throughout the production chain. Several vegetables, including carrot (Daucus carota), can get damaged during long storage periods. For example, temperature and moisture of the storage environment in addition to microbes, affect the quality. The crop losses caused by harmful microbes might be reduced by using biological control methods. The aim of this study was to evaluate if fungal pathogens could be suppressed in stored carrots by biological control. The biological control agent used in this study contains Clonostachys rosea J1446 fungus, which has been tested to be effective against many fungal plant pathogens. Three carrot batches were sprayed with C. rosea J1446 suspension. The carrots were stored in cold storage (0.5 °C) from four to six months. After the storage period, the number of infected carrots was counted and the amount of crop loss was measured. In addition, the survival of C. rosea J1446 fungus on the carrots was examined during the storage period. Pathogenic fungi were identified by molecular biology methods and by morphological features. Some of the fungi were selected for dual culture test examining antagonistic effects of three Clonostachys strains. In this study, the amount of diseased carrots was approximately 33 % of the untreated carrots. Symptom in the tip of the carrot was the most common indication of a disease. Treatment with C. rosea J1446 suspension reduced the amount of diseased carrots by 23 % on average and the treated carrots had less weight loss after the storage period. Viable C. rosea J1446 fungus was isolated from the carrots after six months. Most common pathogens found from the disease symptoms were Botrytis cinerea, Cylindrocarpon spp., Fusarium spp. and Mycocentrospora acerina. The results of the antagonism test showed that the three Clonostachys strains reduced the growth of these pathogens. The results of this research indicate that the C. rosea J1446 product could be used as a biological control agent against fungal pathogens on storage carrots.

More than 75% of global food production benefits from insect pollinators. As the number of pollinators is declining, food security may be at risk. Bees are commonly considered as the most efficient pollinators, and this is reflected in the number of studies on crop pollination by bees. However, other taxa also visit crop flowers and may have a significant role in pollination. Ants are known to visit flowers for many different reasons, but their contribution to pollination is not clear. Raspberry is an economically important crop which highly benefits from animal pollination. The aim of this study was to examine the potential contribution of ants to raspberry pollination, in Coffs Harbour, Australia. The contribution of ants to pollination was evaluated in a bagging experiment comparing fruits from open pollination, ant-only visitation pollination, and exclusion of all pollinators, by recording ants’ abundance and diversity on raspberry flowers by transect walks and examining pollen carried on their bodies by inspecting swab samples under the microscope. The open pollination treatment had significantly higher numbers of drupelets and fruit weight than the pollinator exclusion treatment. The ant pollination treatment resulted in higher numbers of drupelets and fruit weight compared to the pollinator exclusion treatment. The abundance of ants varied considerably in different locations. Ants were the most abundant visitors in half of the studied locations. Ants were more active in the morning, while the proportion of honey bees and stingless bees increased after 11 a.m. compared to ants. Ten different ant species were found to visit raspberry flowers and raspberry pollen was found on ants’ bodies. This study shows the importance of ants in the pollination of raspberry flowers and their influence on raspberry fruit formation. All flower visitors should be studied to establish their relative contribution to crop pollination to ensure growers can plan the pollinator management for each crop and environment separately. This study shows that the role of the ants in crop pollination may have been underestimated.

Weed management is a challenge in organic agriculture and consequently investigation for developing mechanical weed control methods is needed. The aim is to decrease competition between weeds and crop to prevent reduction of the crop yield. Weed control aims at preventing seedbank of the weeds increasing in the fields and weed pressure in the future as well. The effect of the different weed harrowing methods for crop yield and controlling annual weeds in the spring cereal fields were examined in the Mustiala farm as a part of the project “Luomussa vara parempi” for three years. The weed harrowing methods were single post emergence harrowing and combination of pre-emergence and post emergence harrowing. Different weed harrowing treatments were compared with each other and the untreated control treatment. Pre-emergence harrowing was carried out after sowing before emerging of the crop and post emergence harrowing at 2–4 leaf stage of the crop. The most abundant annual weed species was fat hen (Chenopodium album L.) and number of other weed species were proved to be minor during the years of the field experiment. Therefore, the effects of the weed harrowing treatments were concentrated to examine for fat hen. The occurence of fat hen was assessed three times from the experimental plots: before post emergence weed harrowing treatments, after weed harrowing treatments and before harvest. Biomasses of fat hen and yields of the crop were determined in August. Combination of pre-emergence and post emergence harrowing was proved to be the most effective and reliable treatment. Fat hen was controlled substantially by single post emergence harrowing as well. None of the weed harrowing treatments affected significantly crop yield. The smallest crop yield was in the experimental plots of the combination treatment where soil compaction was the greatest due to the weed harrowing. The infestation of fat hen was most effectively decreased by a combination of pre-emergence and post emergence harrowing as well as single post emergence treatment during the next successive years of cereals. Annual reductions in the number of weeds could reduce the yield of the crop in the long term.

Soil acidity limits the growth and development of crops. Yield of plants decreases due to not only low pH conditions in acid soils but also dissolution of detrimental elements affecting the availability of essential nutrients. Aluminum toxicity have been one major cause of decline in yield due to the stunting of the primary root and inhibition of lateral root formation. Plants have ways to mitigate aluminum toxicity which includes Al exclusion mechanisms as a first defense to external Al ions and Al detoxifying mechanisms where Al ions are transported and sequestered inside the plant cells. Vicia faba, commonly known as faba or broad bean is one of the oldest crops grown for being a cheap but excellent foundation of protein in human diets, a good fodder and a forage crop for animals, and one of the most powerful nitrogen fixers. The crop is well adapted to low temperatures but moderately susceptible to hostile subsoils and has very low exchangeable Aluminum tolerance. Responsive varieties were previously identified but mechanisms to counteract with the conditions are still to be realized hence the study aimed to understanding the molecular mechanisms of rootzone aluminum toxicity tolerance in faba bean which was realized by using RNA-Seq technique to analyze the transcriptome of roots of faba bean exposed to acidic and aluminum stressed environment and by then, Al responsive genes were identified. The administration of stress was done in a aquaponics set-up. Results revealed that although gene directly interacting with Al was not identified, faba bean have a variety of well-adapted mechanisms to encounter with the Al stressed condition and mitigate the adverse effects to the plant growth and development which includes (1)transporter activity, (2)signaling(ROS), and (3)ubiquitination. The findings will provide valuable information for designing future crop breeding programs.

Tiivistelmä  Referat  Abstract Lettuce (Lactuca sativa L.) may accumulate high amounts of nitrate in the hydroponic NFT-cultivation system. Accumulation is known to increase under low light conditions, and thus high nitrate content causes problems in year-round lettuce production in Finland. Nitrate is classified as a harmful food additive, and the regulation (194/97) of the European Commission requires the Member States to monitor the nitrate content of commercial lettuce. Hence, to control the nitrate content, farmers have requested an efficient method that does not shorten the shelf-life or negatively affect the quality of lettuce. In the earlier studies, root-applied glycinebetaine (GB) was shown to reduce lettuce nitrate content and increase the contents of amino acids and minerals. The present study aimed to investigate, whether glycinebetaine can serve as a precise method to control lettuce nitrate content in commercial-scale greenhouse production. Glycinebetaine 10 mM was applied into the nutrient solution twice at three days intervals, and lettuce was exposed to treatment during the last six growing days before the harvest. Plant samples were collected every second day for 14 days after the first GB application, and samples from nutrient solution were collected simultaneously. The reduction of GB from the nutrient solution was monitored. The fresh weight of the plants was weighed during the harvest, and contents of nitrate, dry matter, minerals, amino acids, and GB in the plant samples were analyzed. Root-applied GB reduced lettuce nitrate content by over 29 % in comparison to control plants. The total contents of hydrolyzed- and free amino acids were increased. The total content of essential amino acids was increased up to 14 % following the GB treatment. Also, the contents of minerals in the lettuce leaves were altered. The potassium (K+) content in lettuce was reduced by over 40 % after GB application. Lettuce accumulated the applied GB and leaf GB content was 7 mg kg-1 fresh lettuce at the highest. Root-applied GB reduced the fresh weight of the harvested lettuce, but all plants reached the commercial size (>100 g) during the typical commercial growing period of 41–43 days. The result of the present study proved that GB is a practical method to control nitrate content and the quality of lettuce on commercial-scale lettuce production. Glycinebetaine was detectable in the nutrient solution for three days after application and thus, continuously maintained lower nitrate content in plants requires continuous GB application in the commercial lettuce production. The reduction of the nitrate content was significant six days after the first GB application, which indicates that a six-day treatment period is required.

The global demand for berries has grown recently, which is why the berry plants are now being cultivated in the greenhouse during the winter. In Finland, availability of natural light in the winter season is limited, and the light conditions in greenhouses are typically improved with HPS lights, but their spectrum is limited in blue light which is required by plants. LEDs are the first energy-efficient light source that enables the spectrum to be optimized to match the wavelengths absorbed by plant photoreceptors. This study compared the effect of two different light treatments on the primocane raspberry plant (Rubus idaeus L. 'Shani') in winter season. The aim was to study how blue and red LED light in addition to HPS light affect the growth, morphology, yield and berry quality of primocanes in greenhouse conditions during winter in Finland. The experiment was carried out at the University of Helsinki's greenhouses in Viikki between August 2018 and February 2019. In the vegetative stage, amount of vegetative growth, flavonoid, anthocyanin, chlorophyll content and leaf photosynthesis were measured. In the generative stage, the timing of harvest, the number of inflorescences, yield, and the berry quality (soluble solids, titratable acids, total phenolic and anthocyanin content) were measured. Increasing blue and red light in the spectrum (HPS+LED) affected both the vegetative growth and the berry quality compared to HPS light alone. Differences were observed in leaf temperature, photosynthetic activity, leaf chlorophyll and flavonoid content, growth of lateral shoots and berry anthocyanin content. In the vegetative growth phase, the HPS+LED light, contrary to the hypothesis, did not reduce the length of the main shoot, but on the other hand strongly reduced the length of the lateral shoots. HPS+LED light increased the flavonoid and anthocyanin concentration in leaves and berries, respectively, while the anthocyanin concentration in leaves and the total phenolic concentration in berries were not affected. The total yield was less than one kilogram per plant, and not affected by the light treatment. From an economic point of view the marketable yield, along with the berry quality are the key factors when producing raspberries indoor in winter because the plants were grown in completely controlled environment with additional energy. Ultimately, different wavelengths seem to interact, and their mutual relationships change the already known effects of a single wavelength.

Tomatoes (Solanum lycopersicum) are one of the most important food crops in the world. Long supply chains force producers to harvest the fruit before ripening. Ripening then happens in super markets or at the end–consumer. Partly due to the early harvest, tomatoes are perceived flavorless, especially in the wintertime. In addition to a demand for more flavorful produce, consumers are also increasingly interested in healthy food and are looking at the nutritional value of their food before the price tag. As tomatoes are a major crop, they could potentially also contribute to the daily nutrient intake of consumers, such as lycopene, which is i.e. suggested to have preventative qualities towards cancer. Several studies have been conducted to find out how light emitting diodes (LED –lights) could influence the plant and its compounds during growth, but post-harvest research to a lesser extent. Research on post-harvest LED–lighting suggests that quality attributes could also be influenced post-harvest. Important parameters to look at are color and firmness, as they are what buying decisions are primarily based on. Further, lycopene, but also total soluble sugars (TSS) and titratable acidity (TA), and especially their ratio, which defines how tomato flavor is perceived, are worth studying. Therefore, this study aimed to find out, how LED–light treatments could be used to steer the post-harvest quality of tomatoes. Three continuous light treatments were used; Blue, far-red, a standard growing light with high red to far-red ratio and dark as control. The study was done on two cultivars by measuring TSS, TA, lycopene, vitamin C and firmness of the tomatoes every fourth day for 12 and 15 days. Additionally, a set of tomatoes was analyzed for changes in weight and color. The results suggest that LED-lights do influence the quality characteristics of tomato fruit. Blue light seemed to decrease firmness, but to increase lycopene. Lycopene accumulation was also enhanced by a high red to far-red ratio, whereas far-red had a reversing effect. Both blue and high red to far-red ratio treatments increased the chroma values, making the tomatoes brighter in color. Far-red seemed to enhance red color development and to retain firmness, but to decrease lycopene accumulation and to make the color duller. Tomatoes kept in the dark had low lycopene content and a dull coloration. Results on TSS and TA indicate differences in genotype responses, which further underlines the need for further research on the topic and especially the effect of cultivar. The results of the study indicate that tomatoes should not be kept in the dark during storage, as then the full potential of their external and internal quality will not be reached. High red:far-red ratio lighting increases lycopene and brightens the coloration, and could be considered to be used during storage. However, other external factors affecting quality, such as ethylene and temperature, should be included in the future research to study their effect and correlation with light in regard to tomato fruit quality.