Arta Kronberga

This review paper examines the importance of apple tree architecture parameters in breeding programmes, focussing on the roles of canopy volume, tree shape, and fruit-bearing habits in optimising orchard management and breeding efficiency. Canopy volume is a critical indicator of tree growth and productivity, often measured using advanced methods such as LiDAR and UAVs, which provide high-resolution 3D data, especially useful in dense orchards. Tree shape, including branching patterns, angles, and overall structure, plays a key role in optimizing light capture, airflow, space utilization, and tree vigour, which can be efficiently assessed through remote sensing technologies. Early selection of desirable branching traits, such as internode length and branch angle, enables optimisation of tree architecture and improved fruit production in high-density orchards. Fruit-bearing habits, including the timing and position of flowering and fruiting, significantly influence yield regularity and fruit quality and can be analysed using technologies such as photogrammetry, multispectral imaging, and RGB cameras. These tools enable automated identification of key tree characteristics, allowing for better management of tree health, pruning, and fruit-bearing zones. Despite advances in these technologies, further research is needed to better understand the relationship between tree shape, productivity, and longevity, to refine orchard management strategies and improve the efficiency of breeding programmes. This article emphasises the growing role of smart technologies in improving phenotyping and accelerating apple tree breeding processes.

Galium odoratum, commonly known as sweet woodruff, is a perennial herbaceous plant that contains coumarin and is recognized for its medicinal properties. In this study, the influence of sunlight exposure on the phytochemical composition and anti-inflammatory potential of G. odoratum extracts is assessed. The extracts from cultivated and wild-grown plants were analyzed via chromatographic and mass spectrometric methods. In addition, the total phenolic content, antioxidant activity, and effects on macrophage polarization were assessed. The results revealed that while coumarin levels remain stable regardless of environmental conditions, phenolic content and antioxidant activity increase significantly under sun-grown conditions, with chlorogenic acid and rutin identified as major contributing compounds. Additionally, the extracts exhibited anti-inflammatory activity, effectively reducing the M1 macrophage population involved in inflammatory responses. These findings suggest that controlled sunlight exposure can enhance the bioactive profile of G. odoratum. This research highlights the critical role of environmental management in optimizing the medicinal properties of G. odoratum, providing a foundation for its future use in natural therapeutic applications.

The extensive application of synthetic insecticides and herbicides over the past 50 years has led to a number of problems, including negative effects on non-target organisms and the evolution of pesticide-resistant pests. As an alternative means of pest control, plant-based biopesticides have emerged. While developing a new bioinsecticide, allelopathy on both target pests and target crops must be evaluated. We evaluated volatile organic compounds (VOCs), total phenolic content (TPC), total sugars and antiradical activity (ARA), as well as 18 photosynthetic apparatus characterizing functional parameters as stress signaling response to aqueous caraway seed distillation by-product-based extracts. VOCs were detected by headspace gas chromatography mass spectrometry (HS-GC-MS). The caraway extract application decreased “green leaf volatile” C4, C5 and C6 alcohol content in the cucumber leaves. Total phenolic content (TPC), total sugars and antiradical activity (ARA) using high-throughput 96-well plate spectrophotometric methods were tested in dried leaves. No significant changes in these parameters were detected in cucumber leaves after the application of extracts. The caraway extract application did not cause changes in the functioning of the photosynthesis apparatus. Aqueous caraway seed distillation by-product-based extracts can be considered non-phytotoxic to cucumber plants; however, they modify the VOC emissions even ten days after treatment.

The endangered medicinal plant Eryngium maritimum L. faces significant natural and anthropogenic threats. Therefore, in vitro propagation is recommended for both conservation and commercial purposes. The aim of the study was to develop a series of protocols for seed disinfection, in vitro multiplication and rooting, and ex vitro and field adaptation. For explant disinfection, the length and temperature of three consecutive disinfectants were investigated. Macrosalt modifications of MS medium and plant growth regulator addition to media effect on axillary bud propagation rate and rooting was studied. Survival and leaf growth during ex vitro and field adaptation in response to potting media, pot cell diameter, and light spectrum were tested. Seeds treated with diluted detergent at 40 °C for 180 min, followed by 0.01% KMnO₄ for 3 h and commercial bleach for 11 min, achieved a lower rate of contamination and high germination rate. Axillary bud proliferation and rooting were enhanced by reducing nitrogen content in media and adding plant growth regulators. Potting media and pot size affect survival and growth ex vitro. Timely transplantation to field conditions before overwintering increases plantlet survival. In the present work, a suitable foundation is laid to scaleup the production of E. maritimum by micropropagation.

The common dandelion (Taraxacum campylodes G.E.Haglund) is known for its medicinal properties and as a non-toxic, highly nutritious edible plant. Even though the herb is mostly collected in the wild, the food and pharmaceutical industries prefer cultivated plant material. Cultivation offers the possibility to achieve predictable yields, ensure the botanical identity of the plants and products can be certified according to organic or biodynamic standards; therefore the interest in domestication is growing. Due to the scarcity of research on dandelion cultivation in agricultural systems, the current study focused on determining the quantitative and qualitative characteristics of 13 wild populations from Latvia in an organic farming system. Populations collected at Gluda, Priekuli, Mundigciems, Marupe as well as variety TA008 had the highest dry root weight (>100 g per plant) and exceeded the root weight of variety Nouvelle more than two-fold. The highest concentration of chlorogenic acid (CHA) (0.12%) and chicoric acid (CCA) (0.15%) was found in the wild population collected in Turaida. The wild populations from Marupe and Mundigciems had a high average root weight as well as a relatively high CHA and CCA content, making them suitable for commercial growing. The present study examined the feasibility of cultivating wild dandelion populations in an organic farming system. The results revealed a high degree of variation within and between populations; therefore, dandelion wild populations can be used for domestication, breeding and selection of accessions most suitable for the pharmaceutical or food industries.

Glechoma hederacea L. is a medicinal plant that is known in traditional medicine for its anti-inflammatory, antibacterial, antiviral, and anticancer properties. This study evaluated the potential for commercial production of G. hederacea and compared the chemical composition and activity of 70% ethanol extracts and steam-distilled essential oils from wild-grown and cultivated G. hederacea collected in different harvesting periods. The main compounds identified in the 70% ethanol extracts were phenolic acids (chlorogenic and rosmarinic acids) and flavonoid O-glycosides. The essential oil varied in the three accessions in the range of 0.32–2.98 mL/kg⁻¹ of dry weight. The extracts possessed potent antioxidant and anti-inflammatory properties in LPS-treated bone-marrow-derived macrophages. The results of flow cytometry show that extracts from different vegetation periods reduced the conversion of macrophages to the proinflammatory phenotype M1. The chemical composition varied the most with the different harvesting periods, and the most suitable periods were the flowering and vegetative phases for the polyphenolic compounds and essential oils, respectively. G. hederacea can be successfully grown under organic farming conditions, and cultivation does not significantly affect the chemical composition and biological activity compared to wild-grown plants.

The effect of cultivation practises on both the phytochemical profile and biological activity of aqueous ethanol extracts of Chelidonium majus L. was studied. Extracts were prepared from aerial parts of the same plant population collected in the wild and grown under organic farming conditions. Both qualitative and quantitative analyses of alkaloids and flavonoid derivatives were performed by LC/MS methods, and the cytotoxicity of lyophilised extracts was studied in B16-F10, HepG2, and CaCo-2 cells. Coptisine was the dominant alkaloid of extracts prepared from wild-grown plants, whereas after cultivation, chelidonine was the most abundant alkaloid. The total alkaloid content was significantly increased by cultivation. Ten flavonol glycoconjugates were identified in C. majus extracts, and quantitative analysis did not reveal significant differences between extracts prepared from wild-grown and cultivated specimens. Treatment with C. majus extracts resulted in a dose-dependent increase in cytotoxicity in all three cell lines. The extracts prepared from cultivated specimens showed higher cytotoxicity than the extracts prepared from wild-grown plants. The strongest cytotoxic effect of cultivated C. majus was observed in B16-F10 cells (IC₅₀ = 174.98 ± 1.12 µg/mL). Cultivation-induced differences in the phytochemical composition of C. majus extracts resulted in significant increases in the cytotoxic activities of the preparations.

The objectives of the investigation were to identify competitive traits in cereal species in order to contribute to development of a methodology for evaluation of cereal genotypes for their competitive capacity against weeds, which is important for organic breeding aims. The investigation was carried out with spring barley, spring oat, winter triticale and winter wheat genotypes in organic crop rotations in two different locations. Relations between crop traits and weed dry weight were evaluated by Pearson correlation coefficients. The results stressed the significance of some crop traits for cereal competitiveness against weeds for organic breeding purposes: (i) growth habit, canopy height, and crop development rate for spring barley; (ii) crop development rate for spring oats; (iii) winter hardiness and the coefficient of tillering for winter triticale, and (iv) winterhardiness, the coefficient of tillering, the number of productive stems, crop canopy and plant height for winter wheat. It coud be useful to include measurements of crop ground cover for estimating competitiveness of cereal species against weeds