Browsing by study line "Växtproduktionsvetenskap"

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.

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.

Many noble hardwood species of boreal and temperate climate zones will experience increased selection pressure for adaptive traits as climate change proceeds. This will cause shifts in the timing of phenological events such as budburst in spring. Shifts in phenology may disrupt interaction between species and their environment as well as interaction within and between species. Changes in the timing of annual life cycle traits may threaten species’ current fitness and potential to adapt to future climates. The rate and magnitude of phenological shifts will increase along with increasing temperatures. To adapt to changing environmental conditions, species need to possess adaptive variation in life cycle traits. In small and isolated populations at northern margins of species distribution, variation in adaptive traits is threatened by low genetic variation, low gene flow and genetic drift. To preserve the adaptive potential of noble hardwood populations in Finland, ex situ gene conservation collections are established where genetic resources are conserved as living trees. To characterize the adaptive potential currently present in Finnish gene conservation collections of European maple (A. platanoides L.), small-leaved linden (T. cordata Mill.) and European white elm (U. laevis Pall.), the amount of current phenological diversity should be evaluated. For this purpose, budburst progress in the collections was tracked by phenotypic observations on budburst phenological phases in relation to accumulating temperature. The data did not allow for analysis of variance between origin populations; therefore, a more conservative approach was chosen where conserved genetic resources were assessed by examining budburst differentiation between groups of origin populations. The level of differentiation in budburst temperatures is used as an indicator of spring phenological diversity to determine if the conserved origins are adapted to the same spring temperature range. No significant differentiation was found in the timing of budburst between groups of origins. Therefore, the conserved origins are presumed to be adapted to the same spring temperature range within their respective species distribution in Finland. However, low phenological diversity may magnify the threats imposed to these species by climate change. Genetic studies are recommended for deeper understanding of underlying genetic diversity and adaptive potential of the stored genetic resources.

Abstract Background. Faba bean (Vicia faba L.,) is a protein-rich grain crop and a good source of many nutrients. However, the productivity and composition of this crop can be limited by several biotic and abiotic stresses. Acid soil leads to a reduction in water uptake, and influences on major biological and chemical processes. However, some plants can manage stress. Mostly, low pH reduces plant vegetative organs and a has a negative effect on physiological processes such as gas exchange, photosynthesis, chlorophyll concentration, and transpiration. The aim of this study was to find homolog genes in close spp. and o test selected gene response as a factor in resilience to rootzone acidity in Vicia faba L. Methods. Four faba bean genotypes were selected for our experiment based on germplasm screening in aquaponic conditions from a previous study. According to obtained results of morpho-physiological measures from a previous experiment, IG11204 and Bourdon showed tolerance to acid only. DULUC is tolerant to acid and Al treatments. In contrast, Nora38 demonstrated susceptibility to both stresses. Selected genotypes were grown under the same experimental conditions in order to proceed with samples for further analysis (total RNA extraction, cDNA synthesis, RT-PCR, gel-electrophoresis, validation of selected gene by RT-qPCR). Results. Selected genes have been identified as hub genes in A. thaliana (alternative oxidase 1A, glutamate dehydrogenase 1, zinc fingers superfamily protein), which demonstrated an increase in expression levels under acidic pH stress. We have found homolog genes in the Hedin cultivar. Selected homolog gene were used to check its expression in four genotypes under Al3+ and acidic stresses using RT-qPCR. Finally, up-regulation of the GDH1 was detected by acid and also occurred by Al3+ treatments. Discussion. Our analysis of gene expression revealed that GDH1 was expressed differently between control and treated groups. However, its activity was detected for both stresses. The expression of GDH1 transcripts in this study, also concurs with findings where GDH1 in A. thaliana were expressed under Al3+ stress. Furthermore, it was confirmed that they are novel Al3+ resistance genes, which are regulated by the transcription factor STOP1 (sensitive-to-proton-rhizotoxicity1). GDHs are involved in stress tolerance, and pH-regulated metabolic pathways – GABA shunt. It participates in the regulation of cytosolic pH, carbon fluxes into the TCA cycle, nitrogen metabolism, deterrence of insects, protection against oxidative stress, osmoregulation and signaling in plant cells under different stress conditions. The GABA shunt is enhanced by stresses, which cause cytosol acidification. Genes expressed in conditions of low pH partly overlap with those expressed in plants exposed to Al3+ stress. Generally, acidic soil is associated with the co-occurrence of Al3+ and H+ rhizotoxicities.

A well-adjusted regulation of vascular development is crucial for plant growth and development. CLASS III HOMEODOMAIN LEUCINE ZIPPER (HD-ZIP III) genes play a decisive role in cambial stem-cell maintenance, xylem cell fate determination, and ensuring proper patterning of vasculature. LITTLE ZIPPER (ZPR) microproteins are involved in the post-translational regulation of HD-ZIP III via a negative feedback mechanism. The protein-protein docking has predicted that HD-ZIP III and ZPR interact at the b-ZIP domain, which is an evolutionarily conserved region. The expression and mutant phenotype of ZPR in root vasculature haven’t been previously described. In this study, we developed the reporter lines and checked the expression in the Arabidopsis root. ZPR1 and ZPR3 showed a distinct and continuous expression from root tip to elongation and differentiation zone. In the cross-section, the expression was detected in cambium and xylem cells. Unlike ZPR1, ZPR3 showed a stronger expression towards the phloem side. Although ZPR2 didn’t show any endogenous expression, expression was detected in the primary root tip and lateral root initiation site upon xylemin treatment. Exogenous auxin application increased the expression of ZPR3, but it required a longer response time. The expression results suggest that ZPR follows the HD-ZIP III expression pattern, however, each ZPR shows some variation from the others. In the mutant analysis, zpr1 showed increased cellular proliferation in the vasculature, but zpr2 had no difference compared to the wild type. The results suggest that ZPR and HD-ZIP III have their function in a similar region in the root vasculature. However, further empirical evidence is necessary to elucidate the interaction of HD-ZIP III and ZPR, and its role in the regulation of root vascular development.

Indoor gardening is continuously increasing among consumers. Consumers and greenhouse entrepreneurs are looking for ways to optimize growing conditions for their plants to produce high quality and good yield. So far, the effects of LED lights on the plant biomass production and on the composition of volatile aroma compounds have been investigated. However, the effects of different lights on the taste and odor of homegrown herbs is yet to be discovered. The aim of this study was to investigate how different light conditions would affect the composition of compounds that are mainly responsible for the specific flavor of selected model plants. The main goal was to investigate what type of volatile compounds could be obtained in plants grown under different light conditions. The second goal was to investigate how non-volatile saliva soluble compounds could be modified due to the different growing conditions. Coriander and dill were selected as model plants. Coriander is globally utilized herb while dill is one of the most used herbs in the Nordic countries. Due to their strong flavor, both of these herbs divide consumer opinions and therefore investigation of their flavor modification is important. Coriander and dill were grown in domestic smart gardens manufactured by Plantui Oy. Used light conditions included control, green and blue light. Control light composed of a combination of blue, green and red light. Light source was LED lights. The herbs were grown at +22 °C and at humidity of 56.5 %. Used nutrients were ready-made mixtures by Plantui Oy. The composition of artificial saliva was optimized with commercial coriander and dill for the investigation of flavor compounds. Coriander and dill samples were extracted with the developed artificial saliva after which the volatile compounds were analyzed by a combination of gas chromatography and mass spectrometry (GC-MS) and non-volatile compounds by a combination of liquid chromatography and mass spectrometry (LC-MS). Principal component analysis (PCA) was utilized to investigate the composition of volatile compounds while partial least squares-discriminant analysis (PLS-DA) was used to investigate the differences in the non-volatile compounds. Used light conditions altered the chemical composition of herb leaves. Also, light conditions had a visible effect on plant growth. For example, herbs grown in blue light germinated weakly and produced less biomass. The profile of volatile compounds in corianders grown under green and blue light differed from those grown under control light. For dill, the profiles differed only for the samples grown under blue light. Majority of the volatile compounds were components of the essential oils of herbs and compounds that enhance stress tolerance. When looking at saliva soluble non-volatile compounds, coriander grown under blue light was different from the one grown under control light while for dill a difference was observed both under blue and green light. Based on the results, special light recipes can be developed to modify the flavor of coriander and dill. Further research is still needed, especially on the effects of light conditions in plant cell signaling and thereby on the morphological changes in plants and as a consequence on their flavor compounds.

Organic agriculture is growing steadily in Europe. Demand for organic products and pressure from policy changes in the EU have created a need for organic seed material. One of the limiting factors is the lack of organic variety testing. Currently no official organic Value of Cultivation and Use (VCU) trials or standards for organic variety testing excist in the EU. Plant breeding companies like Boreal Plant Breeding want to offer varieties for organic farmers but they lack information on the performance of their varieties in organic conditions. The main objective of this experiment was to determine the most important variety traits in organic agriculture in Finland and which of the Boreal Plant Breeding oat varieties exhibit the most favourable traits for organic growing conditions. Relationships between observed traits were also examined. A wide range of observations and measurements were performed from the trial throughout the growing season. Quality analysis of the yield were performed after harvest. The objects of examination during growing season included growth development, leaf area index (LAI), nutrient status with SPAD (Soil and Plant Analysis Development) measurements, plant height and yield components. Plant height and LAI appeared to be the best indicators for evaluation of performance potential of oat in organic conditions. SPAD value wasn’t found to have a connection to oat yield nor was it an indicator for oat LAI. High LAI increased oat height, yield and yield component shoots/m2 but effected negatively on the yield component panicles/m2 during the end of stem elongation. Plant height was a good indicator of yield level. The number of weeds and LAI value didn’t have a connection in this experiment and neither did weed number and yield. The early and late varieties varied in their reaction to the low-input growing conditions. Early varieties had generally lower yield but better yield quality than the late varieties. ‘Nella’ showed potential to be a variety with good yield quality and high yield in low-input conditions in Southern Finland. Area of cultivation and the end use of the oat are important factors in variety selection.