Institute of Forage Crops

The identification of wheat genotypes with balanced grain yield, stability, and antioxidant response to abiotic stress is crucial for creating adaptable varieties in changing climates. The research was conducted as a multi-environment trial (MET) across six environments (three localities over two seasons), and included 15 wheat genotypes (bread wheat lines, standard varieties and two spelt wheat lines). This study integrates AMMI and GGE biplot analyses with antioxidant profiling across growth stages to identify genotypes combining yield stability and stress tolerance. Lines KG-4/1, KG-11/1 and the variety Pobeda were identified as high-yielding and stable genotypes, with KG-11/1 ranked as an “ideal genotype” and KG-4/1 achieving the highest grain yield on MET level (6.48 t ha–1). Specific adaptation of genotypes KG-40/1 and Renesansa indicates their potential for targeted breeding in particular environments. Antioxidant parameters (TPC and DPPH• scavenging activity) at early growth stages were positively correlated with grain yield, indicating that they can serve as suitable biochemical markers for selecting stress-tolerant, high-yielding wheat genotypes. This comprehensive approach, which includes the analysis of grain yield stability/adaptability and antioxidant parameters, is adequate for the evaluation of promising lines that may be suitable genetic resources in climate-resilient wheat breeding programs.

Mixed cultivation of grass-legume forage crops, such as lupine (Lupinus albus L.) and barley (Hordeum vulgare L.), offers significant advantages in terms of nitrogen utilization, stress resistance and a balanced diet for ruminants. This study explored the symbiotic effects of these crops on photosynthesis and stress tolerance via measuring key physiological and biochemical parameters. Measurements were performed on the photosynthetic activity, chlorophyll and carotenoid content, glycolate oxidase activity, antioxidant capacity, and total phenolic content. The varying temperatures during May, allowed the effects of mixed cultivation on the response to chilling to be analyzed. Notably, barley monoculture was the most affected by the decreased temperatures. In general, mixed culture showed mitigation of the effects from chilling, as compared with both lupine and barley monocultures alone. These results suggest an adaptive synergy between lupine and barley, highlighting the potential advantages of mixed cultivation for improving stress tolerance and overall crop performance.

Abstract Sorghum bicolor (L.) Moench is a resilient cereal crop that thrives in arid conditions and produces substantial yields following periods of drought. However, sorghum crop productivity is threatened by insect pests, such as Sitobion avenae Fabricius, a common aphid species on sorghum. The research included seven sorghum hybrid lines between 2021 and 2023. The study aimed to evaluate the cyanogenic glycoside content in these lines, their sensitivity to aphid infestation, and the effect of S. avenae attack on the integrity of plastid pigments and the alteration of leaf chlorophyll fluorescence parameters. Aphid infestation occurred under natural field conditions. The study revealed the classified very low‐sensitive hybrids (L №305 and Whiteseed) exhibited a significantly lower density of S. avenae , attributable to a substantially more elevated concentration of cyanogenic glycosides in non‐infested plants and a significant decrease in glycosides in infested plants. Changes in carotenoid and chlorophyll contents and chlorophyll fluorescence parameters in infested hybrids showed a slight reduction. This led to a stronger protective and antibiotic effect on the host plants and weaker aphid performance. The medium‐sensitive hybrids (L №302 and L №256) exhibited a significantly higher aphid density because of a lower cyanogenic glycoside content in non‐infested hybrids and a considerably more violent decrease in glycosides in infested hybrids. Aphid infestation resulted in a considerable reduction in chlorophyll and carotenoid levels and a pronounced decrease in photosynthetic parameters. This showed the sensitive plants' stress response to aphid invasion. The study's findings enhance the understanding of how aphid infestation levels impact sorghum plants. This understanding is essential for identifying and selecting resistant sorghum varieties. These traits are pivotal in determining crop yield, thus serving as crucial indicators for future research endeavours concerning aphid resistance in sorghum.

This study analyzes the impact of different nitrogen fertilization levels, in the form of UREA, on the growth and yield of spinach (Spinacia oleracea L.) under greenhouse conditions in Raška during the 2022 and 2023 growing seasons. The experiment was set up using a Randomized Complete Block Design with three replications, on a 12 m² plot. UREA (46% N) was applied in various rates (0, 40, 80, 120, and 140 kg ha⁻¹) to evaluate its effect on spinach growth and productivity. Key parameters such as plant height, days taken to first cutting, number of leaves per plant, leaf length, fresh weight of leaves, and yield per pot and hectare were measured. The results showed significant differences in most of the analyzed parameters. As the N rate increased, plant height, number of leaves per plant, leaf length, and yield increased, with the highest values recorded at 140 kg ha⁻¹. However, excessive doses showed diminishing returns, particularly between 120 kg ha⁻¹ and 140 kg ha⁻¹. The control group exhibited the lowest values for all parameters. Additionally, earlier flowering and potentially reduced quality with higher nitrogen doses were observed. The study concludes that optimal nitrogen levels are crucial for spinach yield and quality, and a balanced approach to fertilization is necessary to achieve sustainable production while minimizing environmental risks.

The study aimed at analyze the quantitative traits of pea genotypes through the values of genetic parameters and to identify the traits that determine the productivity of F1 and F2 hybrid plants. Three year field experiment was conducted in the Institute of Forage Crops - Pleven, Bulgaria. The crosses (CA1P ? L020140; CA1P ? Wt6803 and their reciprocal) between pea varieties L020140 - Pisum sativum ssp. arvense, Wt6803 - Pisum sativum var. hiemale and CA1P - Pisum sativum ssp. sativum were studied. Positive true heterosis was detected at crosses L020140 ? CA1P and CA1P ? L020140 by fresh root weight and nodule weight; CA1P ? Wt6803 by root length and nodule weight and CA1P ? L020140 by plant height at both limits of the environment. It is evident that the root weight and number of nodules per plant at CA1P ? Wt6803 and the weight of fresh biomass at CA1P ? L020140 are inherited with a clear positive dominance or over-dominance. The dominance or over-dominance of Wt6803 ? CA1P by root length and fresh root weight, number and weight of plant nodules; at CA1P ? L020140 by number of nodules and at L020140 ? CA1P by weight of nodules per plant were found negative. In more favorable growing conditions, epistatic gene interactions play a greater role in the inheritance of traits and the number of nodules in CA1P ? Wt6803 and L020140 ? CA1P, and for dense sowing at L020140 ? CA1P and CA1P ? L020140 by fresh aboveground biomass weight and nodule weight. Dominant gene actions were of greater importance for the number of nodules per plant at Wt6803 ? CA1P. High inheritance rates in both environments are characterized by hybrids Wt6803 ? CA1P and L020140 ? CA1P by fresh root weight and number of nodules per plant, and all hybrids by number of nodules. For almost all crosses, the efficiency of the team is negative and at both limits of the environment, which implies that the mass team will be more effective if it starts early in F4-F5 and is based on plant height, fresh weight of aboveground biomass and fresh weight of roots.

There is a need for comprehensive research on the species structure and the population dynamics of the most common aphidophagous species. A critical factor of the effectiveness of aphid biocontrol is the ratio of beneficial polyphagous (generalist) to oligo- or monophagous (specialist) species within the various trophic groups. Aphids' population density and environmental conditions influence the development and potential feeding of useful insects. The present study aimed to determine the community structure, relationships and diversity between aphids and their aphidophagous species in alfalfa fields using the following methods: sweeping with an entomological net, the quadratic method, coloured sticky board method, route survey method and visual observations. Research on the structure of the aphid-aphidophagous community revealed that aphidophagous species belong to three groups: (1) polyphagous predatory bugs from the families Anthocoridae and Nabidae, (2) oligophagous and polyphagous predators from the families Coccinellidae, Syrphidae and Chrysopidae; and (3) monophagous and oligophagous parasitoids, primarily from the families Aphidiidae and Ichneumonidae. From mid-May to June, there was a sufficiently large potential for aphidophagous species (Coccinellidae, Syrphidae, Chrysopidae, Anthocoridae and Nabidae) to control aphids, while in September, predatory ladybirds from the Coccinellidae family were the main biological control agents. Coccinellidae (Coleoptera) exhibited the highest values of diversity, dominance and richness indices among insect groups in the aphid-aphidophagous community. The existence of diverse aphidophagous species in alfalfa fields suggests that these predators can complement each other, leading to effective biological control of aphids. The synergy among different predator species holds promise for enhancing the overall efficacy of integrated pest management strategies.

The present study aimed to determine the influence of rearing method on behaviour and welfare in Assaf lambs during the first two weeks of the neonatal period, in an intensive rearing system. The experiment was conducted with 24 Assaf lambs, in which two methods of management were applied – natural rearing (NR) and artificial rearing (AR). Forced separation of lambs from their mothers caused 74% fewer suckling attempts during the first three days of the neonatal period, which reduced suckling time by 57%. The lambs reared under NR, spent more time moving and less time standing and lying. Overall, it was found that the type of rearing affects the suckling time. Artificial rearing decreased lying and playing time, which is indicative of the improved welfare of NR lambs. The two rearing methods (NR and AR) did not affect blood total protein or albumin, indicating no significant effect of different rearing methods on these haematological variables. Artificial rearing does not disturb the welfare and behaviour of the animals when it is done correctly and stress appears transient and animals quickly adapt with similar growth rates.

Protocol for the determination of free and protein-bound DA and NE, 5HT and Ach and their metabolites and oxidation products by UPLC-MS/MS method

The experiment was carried out on an experimental field of Institute of Plant Genetic Resources “K. Malkov”, Sadovo during the period 2016 - 2018. Nineteen common winter wheat lines and variety Sadovo 1 were studied, under the controlled trial conditions. The purpose of the research is technological evaluation and determination of the stability of traits in breeding materials in the early generations. The analyzes were carried out in a laboratory to assess the technological qualities of the grain. For the characterization of the studied lines, the following traits were taken into account: sedimentation value (SV) - using a 2% solution of glacial acetic acid (Pumpyanskiy, 1971); fermentation number FN - Pelshenke test (PT) by mixing a sample with live yeast in two repetitions (Pelshenke et al., 1953). The traits stability of breeding material was evaluated by the stability variances σi2 and Si2 according to Shukla (1972), the equivalency Wi according to Wricke (1962) and the criterion of phenotypic stability (Ysi) according to Kang (1993). The program product IPCSSVKYSI (Interactive program for calculating Shukla’s stability index (Ysi), developed by Kang & Magari (1995) was used to determine the stability index. The highest value for the trait sedimentation value was reported for line RU 32/2072.73.74, followed by line RU 47/3504. With a high value of the trait fermentation number are the lines RU 32/2072.73.74, RU 91/1729; RU 93/1895 and RU 128/2900. The influence of the factors genotype, environment and their interaction on the phenotypic appearance of the studied traits has been significant. The following lines can be highlighted as valuable breeding materials: RU 32/2072,73,74 and RU 47/3504 (high value and stability of the traits of sedimentation value and fermentation number). RU 49/2300 (high value and stability of the trait sedimentation value). RU 91/1729 (high value and stability of the trait fermentation number) The listed genotypes can be successfully used in breeding and improvement work to create new and high-quality common winter wheat varieties.

With a very diverse structure and small molecules, phytohormones are regulators of plant growth and development. Despite the fact that they are synthesized by plants in small quantities, they are highly active physiologically. According to their action, phytohormones can be divided into two categories, as either activators of plant growth and development or as inhibitors, with auxins and cytokinins belonging to the former group. Auxins are synthesized by plants in the apical meristems of shoots, but also in young leaves, seeds, and fruits. They stimulate the elongation growth of shoots and initiate the production of adventitious and lateral roots. Cytokinins, in turn, are formed in root tips and in unripe fruits and seeds. These hormones are responsible for stimulating the growth of lateral shoots, they also stimulate cytokinesis and, consequently, cell division. The aim of this review paper is to present the progress of the research on the effect of selected auxins and cytokinins on crops, considering the prospect of using them in plant growing methods.