Selenium (Se) is a nonmetal that is essential for humans and other animals, and is considered beneficial for plants. The bioavailability of Se strongly influences its content in the food chain. Soils are the main source of Se, and their Se content primarily influences its availability, along with other soil properties. A field survey was conducted on soils of Southeast Europe, specifically in Croatia (Osijek), Bosnia and Herzegovina (Sarajevo, Banja Luka, Mostar, and Prud), and Serbia (Novi Sad). Soil samples were taken from the arable soil layer (0–30 cm depth), and two types of Se availability were measured: Se extracted using pure HNO₃ (Se_Tot) and Se readily extracted in water (SeH₂O). Only soils from the Mostar area had Se concentrations above deficit levels (0.5 mg kg⁻¹), with the highest values of cation exchange capacity (CEC), soil organic matter (SOM) measured as loss of ignition (LOI), total C, total N, Zn_Tot and Cd_Tot. The connections between the chemical characteristics of the soil and SeH₂O were investigated. Principal component analysis (PCA) explained 73.7% of the variance in the data set in the first three principal components (PCs). Using the provided data, we developed a partial least squares (PLS) regression model that predicted the amount of SeH₂O in the soil, with an accuracy ranging from 77% to 90%, depending on the input data. The highest loadings in the model were observed for LOI, CEC, total C, total N, and Se_Tot. Our results indicate the need for biofortification in these key agricultural areas to supplement the essential dietary requirements of humans and livestock. To efficiently and economically implement biofortification measures, we recommend utilizing regression models to accurately predict the availability of Se.

Common buckwheat (Fagopyrum esculentum Moench.) has a long history of cultivation in the large, mountainous regions of Bosnia and Herzegovina (B&H). Its commercial production is mainly based on the regionally bred variety ‘Darja’, but numerous landraces are also being grown on a smaller scale. As part of the SEEDNet (Southeast European Network on Plant Genetic Resources) project, these landraces have been collected and stored at the Gene bank of the Faculty of Agriculture and Food Sciences in Sarajevo (FAFS). To assess their utilization value, it was first important to investigate if they represent distinct landraces and to identify their genetic relationships with the most commonly grown varieties in the region (‘Darja’, ‘Goluba’ and ‘Čebelica’). Therefore, the aim of this study was to assess the genetic relationships and diversity of the common buckwheat accessions maintained at the FAFS Gene bank, as well as the value of these accessions for future breeding programs, using microsatellite markers and seventeen quantitative and fifteen qualitative morphological traits. The FCA (Factorial Correspondence Analysis) and AMOVA (Analysis of Molecular Variance) revealed that several accessions represent completely distinct landraces which clearly differentiated from the most commonly grown cultivars ‘Darja’ and ‘Goluba’. Conducted morphological analyses revealed that several of the analyzed landraces hold similar characteristics to the ones observed in ‘Darja’ and ‘Goluba’, while others possess unique traits potentially useful in breeding programs.