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Assessment of new citrus hybrid rootstocks to salinity at the early seedling stage under greenhouse conditions
(Estonian University of Life Sciences, 2024) Majji, M.; Chetto, O.; Talha, A.; Bouaaza, G.; Beniken, L.; Benkirane, R.; Benyahia, H.
The citrus industry in arid areas is largely constrained by the salinity of irrigation water and soil. This study was conducted to determine how six novel citrus hybrid rootstocks will respond to salinity at the seedling stage. Three different NaCl concentrations, 0, 2, and 5 g L-1, were added to the half-concentrated Hoagland solution (corresponding to 1.3 (control), 4 and 9 dS m-1, respectively). Three-month-old seedlings grown in greenhouse conditions and transplanted in plastic pots were used. After two months of stress, different responses from the rootstocks and salt levels were observed. The addition of NaCl to the irrigation solution considerably decreased the fresh and dry weight and leaf chlorophyll content. Additionally, the proline content, soluble sugar, and the leaf chloride content increase with the increase in salinity. Our findings demonstrated that the hybrid Poncirus Trifoliata× Citrus reshni Hort. ex Tan. (V5) H6 is salt-sensitive, accumulating a high leaf chloride level of 46.92 mg g-1 of dry matter and a low chlorophyll content of 1.12 mg g-1 of fresh matter associated with signs of leaf toxicity, leading to poor fresh and dry weight. Although hybrid Poncirus Trifoliata× Citrus reshni Hort. ex Tan. (V1) H2 is thought to be salt-tolerant, it accumulates 38.88 mg g-1 of dry-matter leaf chloride and 1.72 mg g-1 of fresh-matter chlorophyll content.
Evaluation of grain morphometry and gliadin diversity among twenty accessions of the genus Aegilops from the National collection of Bulgaria
(Estonian University of Life Sciences, 2025) Desheva, G.; Petrović, G.; Valchinova, E.; Deshev, M.; Kyosev, B.; Pencheva, A.
The objective of the study was to evaluate the genetic diversity in twenty Aegilops accessions belonging to five plant species with respect to specific grain morphometric parameters and gliadin proteins, employing digital image analysis and A-PAGE electrophoresis. The considerable variation was observed among accessions for grain morphometric traits - area, perimeter, length, width and colour of grain. A total of 96 gliadin polymorphic bands were identified, with the number of bands varying between 13 and 22 per accession. The overall genetic diversity in the samples based on the patterns observed for each of the four gliadin regions showed that the ω, γ and β regions had high genetic variation index (H = 0.950), while α regions (H = 0.938), respectively. The mean genetic diversity estimate was high (H = 0.947). The average genetic similarity between all 20 genotypes ranges from 0.14 to 0.93 with a mean of 0.56, indicating that the studied accessions exhibited considerable genetic variability. The study found that the clustering of Aegilops genotypes was not linked to their geographic origin. Two-dimensional Principal Coordinates Analysis (PCoA) based on the gliadin and morphometric analyses revealed wide genetic dissimilarity between most of the genotypes, explaining 97.16% of the variations, with the model explaining 97.16% of the observed variation. Of this, PCo1 accounted for 93.65% and PCo2 for 3.51%. Genotypes with analogous genomes were grouped in close proximity within the phylogenetic tree, indicating that their evolutionary relationships may have originated from the same parental lineage.
The impact of straw application on growth dynamics and proline accumulation in drought-stressed rice
(Estonian University of Life Sciences, 2025) Ria, R.P.; Kartika, K.; Lakitan, B.; Sulaiman, F.; Meihana, M.
The frequent occurrence of unpredictable extreme droughts necessitates investigating measures to mitigate their impacts, as drought may occur at any growth phase of rice. This study evaluated the efficiency of straw applications to conserve soil moisture and mitigate the negative effect of drought stress on rice in tropical riparian wetlands. Rice straw was applied as organic matter (S1) and as mulch (S2) and then subjected to drought stress during early vegetative (D1), late vegetative (D2), and generative (D3) phases. The result of this study showed that the utilization of straw slowed down the water loss through evaporation as indicated by soil moisture. However, both rice straw applications, organic matter and mulch, were inefficient in maintaining the optimum plant growth when the soil moisture declined to < 10%. Drought stress at the early vegetative phase reduced the number of leaves by 63.68%, the number of tillers by 50.58%, and the total leaf area by 72.36%. Drought stress at the early vegetative phase also delayed flowering time for 11 days. Meanwhile, drought stress during the generative phase reduced the number of filled spikelets by 45.18% and increased sterile spikelets to 247.05%, which significantly reduced the yield. Plants that experienced drought stress during the vegetative and generative phases eventually increased the proline content by about 10 times (18.47 mmol g-1) compared to unstressed plants (1.62 mmol g-1). Straw mulching is recommended for mild to moderate droughts, but additional methods are needed to maintain soil moisture below 10%.
Insight on the impacts of brassinosteroid- and seaweed-based biostimulants on glyphosate-resistant commercial crop growth, yield and soil microorganisms: A scoping review
(Estonian University of Life Sciences, 2025) Tandathu, T.E.; Van Der Watt, E.; Kotzé, E.; Khetsha, Z.P.
Globally, compliance with the chemical regulations on the use of herbicides, particularly glyphosate, remains a challenge. Glyphosate controls various broadleaf, annual, and perennial grasses in the agricultural and non-agricultural sectors. Although glyphosate targets weeds, it can also influence non-target soil microorganisms and high-value plants through earlyseason broadcast, pre-plant application, or indirectly via foliar application by droplets falling to the ground. In plants, glyphosate impacts various physiological and physiochemical processes, inhibits auxin transport, and enhances auxin oxidation in plants. Hence, biostimulants serve as a gateway in alleviating such problems. Biostimulants are agricultural products manufactured from natural materials that contain active compounds, which stimulate growth when applied in minute volumes under different growth conditions. In the past, a major focus was directed toward biostimulants' effects on commercial crops under abiotic stress conditions such as drought, heat, and salinity. However, less emphasis has been placed on the stress caused by herbicide applications. Therefore, this review focuses on future studies to explore brassinosteroid and seaweed-based biostimulants' impact on glyphosate-resistant commercial crop growth and soil microorganisms. Conclusions and recommendations could be reached using the pool of research material, which consists of research articles, reviews, book chapters, theses, research short communications, and industrial short communications from at least the last ten years.
Preliminary study of microplastics in bottled and tap water in Estonia
(Estonian University of Life Sciences, 2024) Meitern, Annika Joy; Neilant, Keith; Raamets, Jane
Microplastics (MPs) are a growing environmental concern due to their widespread occurrence and potential harmful impacts on ecosystems and public health. This preliminary study -assesses the prevalence of MPs in bottled and tap water in Estonia and reviews related research in the field. The study aimed to evaluate the occurrence of MPs and understand the potential influence of the water source and packaging material on water properties. The study encompassed 12 different bottled water products from 9 Estonian brands and tap water samples from Tallinn and Tartu. All the tested water samples contained MPs, predominantly fibers, with blue and transparent being the most common colors. The packaging material, bottle caps, or the water source did not influence the number of MPs found in bottled water. Interestingly, water packaged in glass bottles contained a higher count of MPs than in plastic bottles and tap water. The study underscores the need for further research to determine the sources of contamination.
Productive and biochemical responses of Marandu grass under fertilization protocols
(Estonian University of Life Sciences, 2025) Dutra, I.C.; Pires, A.J.V.; Jardim, R.R.; Silva, H.S.; Santos, B.E.F.; Silva, N.V.; Ribeiro, A.S.; Dutra, G.C.; Filho, C.A.A.O.; Publio, P.P.P.; Silva, A.P.G.; Nogueira, M.S.
The aim of this study was to evaluate the effects of liming and chemical fertilization protocols, containing different combinations of nitrogen (N), phosphorus (P) and potassium (K), on the photosynthetic pigments, productive characteristics and carbohydrate concentration of Urochloa brizantha cv. Marandu. Five fertilization protocols were evaluated (PK fertilizer combination; NP fertilizer combination; NK fertilizer combination; NPK fertilizer combination; and without fertilizer - control), associated or not with soil correction via liming, in a completely randomized design, with four replicates. The experimental units consisted of plastic pots with a capacity of 12 liters, which were filled with 10 dm³ of sandy clay loam soil. Seeds of Urochloa brizantha cv. Marandu, with 80% cultural value were used. With the corrected soil, the NP protocol provided greater production of dry mass of residue (PMSRE), root volume, leaf area, leaf area index, total sugar content (AST) and starch in the root, compared to the other protocols. Without liming, the NP protocol provided greater production of aerial part dry mass (PMSPA), root volume, leaf aerial volume, leaf aerial index and AST content in leaves, roots and residue. The NPK protocol, with liming, was 73% higher in chlorophyll a content, 50% in carotenoid content, 90% in PMSPA, 78% in leaf area and 76.2% in leaf area index, compared to the soil without correction. The use of NP fertilization with liming is recommended as it provides positive responses on the photosynthetic pigments, productive characteristics and total sugar content of Marandu grass.
Toxicity of insecticides for adults of Diceraeus melacanthus Dallas, 1851 (Hemiptera: Pentatomidae) in three exposure modes
(Estonian University of Life Sciences, 2025) Vieira, E.C.S.; Ávila, C.J.; Vieira, M.C.S.; Silva, P.G.
Phytophagous stink bugs are considered the important pest in second-crop corn cultivation in Brazil, especially when they occur during the early stage of plant development. This study aimed to evaluate the efficiency of insecticides in controlling adults of the Diceraeus melacanthus (Dallas, 1851) stink bug when applied separately in three different modes of exposure. The treatments were evaluated in three modes of exposure of insecticides to D. melacanthus adults as described below: direct contact (direct application of the insecticide to the insects); tarsal contact (exposure through their walking on the treated surface) and ingestion (contact through their feeding on previously treated fresh bean pods). Mortality was assessed at 1, 5, 24 and 48 hours post-exposure. We observed that the percentage of accumulated mortality of D. melacanthus adults was significant through direct contact with chemical treatments. However, if the target insect does not receive direct spraying on its body, indirect contact through its tarsus walking on the treated surface can guarantee a significant final mortality of the stink bugs. In addition, although the mode of exposure through ingestion has shown low mortality, it may also contribute to the final mortality of stink bugs in the field depending on the chemical treatment applied to the crop.

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