Avena fatua is an economically detrimental weed found in cereal growing areas worldwide. Knowledge about the variation of dormancy and germination characteristics, as well as of the genetic diversity and structure can provide additional information about different populations within a region. Identification and development of potential indicators or markers of seed germination behavior, would be useful for modelling emergence and seed bank dynamics. This study aimed to describe the initial germination, dormancy, and morphological characteristics of seeds from different Latvian populations of A. fatua and to investigate the genetic structure of local populations. Seed samples from 26 to 41 locations in different regions of Latvia were collected over three years. Seed morphology, initial germination, and the effect of dormancy-breaking treatments were determined. Seeds from 18 Latvian populations with contrasting seed dormancy characteristics were genotyped. Although morphological differences between seeds from different regions were revealed, genetic analysis of the selected populations indicated that the population structure was not related to geographical location, which probably reflects the impact of anthropogenic dispersal of A. fatua seeds. The effect of dormancy-breaking treatments varied between years, between climatic zones and between populations, indicating environmental influences as well as inherited dormancy.

Accurate and robust methods are needed to monitor crop growth and predict grain yield and quality in breeding programs, particularly under variable agrometeorological conditions. Field experiments were conducted during two successive cropping seasons (2021, 2022) at four trial locations (Estonia, Latvia, Lithuania, Norway). The focus was on assessment of the grain yield (GY), grain protein content (GPC), and UAV-derived NDVI measured at different plant growth stages. The performance and stability of 16 selected spring wheat genotypes were assessed under two N application rates (75, 150 kg N ha⁻¹) and across different agrometeorological conditions. Quantitative relationships between agronomic traits and UAV-derived variables were determined. None of the traits exhibited a significant (p < 0.05) genotype-by-nitrogen interaction. High-yielding and high-protein genotypes were detected with a high WAASB stability, specifically under high and low N rates. This study highlights the significant effect of an NDVI analysis at GS55 and GS75 as key linear predictors, especially concerning spring wheat GYs. However, the effectiveness of these indices depends on the specific growing conditions in different, geospatially distant locations, limiting their universal utility.

The objectives of this study were to identify stable and high-yielding genotypes grown in organically managed fields in Latvia and Estonia and to determine their canopy parameters and susceptibility to seed-borne diseases. Field trials with barley (Hordeum vulgare L.) were conducted using 26 varieties and breeding lines including 20 covered and six hulless genotypes at three locations over three growing seasons. Estonian breeding line 4533.4.3.6 yielded significantly above the average (3.99 t ha^–1; LSD = 0.230 t ha^–1) and showed wide adaptability as indicated by the coefficient of regression (b_i = 1.05), relatively small deviation from regression (s²d = 0.04) and one of the lowest value of ecovalence (W_i = 1.41%). There were significant differences between genotypes according to the canopy parameters measured, such as growth type, early vigour, crop ground cover and canopy height. High-yielding barley genotypes were characterized by more planophile growth habit and shorter canopy height, thus providing good ground cover in the early stages of plant growth. Rasa was the only variety found to have no plants infected with loose smut or leaf stripe, in either of the locations.

Diversity within a crop of self-pollinating species can provide advantages in sustainable farming, including the ability to adapt to environments. However, few results proving the benefits in various species and climatic conditions are available. Our aim was to find the differences between heterogeneous and homogeneous materials and determine if crossing has advantage over mixing. We compared essential traits of twelve heterogeneous spring barley composite cross populations (CCPs) to those of seven mixtures representing similar genetic backgrounds and five homogeneous varieties in nine organic and three conventional environments over the course of three years. We found significant advantages for heterogeneous materials, particularly CCPs, for yield in organic and stress environments as well as yield stability, N utilisation efficiency, protein content, 1000-grain weight, and net blotch severity and observed positive trends for N uptake efficiency and weed competitiveness. CCPs’ advantages over mixtures were for protein content and 1000-grain weight, a nonsignificant yield gain in low-yield and stress environments, higher yield stability, and minor positive trends for net blotch, NUE, and weed competitiveness. We suggest heterogeneous populations as valuable alternatives to uniform varieties for organic and poor cultivation environments. Although multi-component mixtures could provide a performance similar to CCPs, considering the adaptation potential, populations would be more advantageous overall.

This study aimed to evaluate the performance and stability of agronomic and grain quality traits of 11 spring barley varieties from the Latvian breeding programme grown in two locations for four years. The study was carried out on 11 Latvian spring barley varieties: nine covered varieties ‘Abava’, ‘Ansis’, ‘Austris’, ‘Didzis’, ‘Gāte’, ‘Idumeja’, ‘Jumara’, ‘Kristaps’, and ‘Saule PR’ and two hull-less varieties ‘Irbe’ and ‘Kornelija’. Plants of the varieties were grown in field trials of the Institute of Agricultural Resources and Economics, at two sites (Priekuïi and Stende) during 2014–2017. Varieties ‘Didzis’, ‘Jumara’, and ‘Ansis’ yielded significantly above the grand mean in eight environments (5.70 t·ha ⁻¹ ; LSD = 0.476 t·ha ⁻¹ ). ‘Didzis’ showed relatively high dynamic yield stability and broad adaptability to all environments (b _i = 0.90; b = 1; s ² _d = 0.07). Grain yield for varieties ‘Jumara’ and ‘Ansis’ showed specific adaptability to unfavourable environments (b _i = 0.48 and 0.55, respectively; b _i < 1). Some covered spring barley varieties were considered to be the best in eight environments with stable and high 1000 grain weight (‘Austris’, ‘Idumeja’), test weight (‘Gāte’, ‘Jumara’, ‘Austris’), lodging resistance (‘Austris’, ‘Jumara’, ‘Didzis’), resistance to Pyrenophora teres (‘Didzis’, ‘Saule PR’) and Blumeria graminis (‘Saule PR’, ‘Didzis’). Both hull-less barley varieties ‘Irbe’ and ‘Kornelija’ were distinguished for high crude protein and ß-glucan content.