The experimental study was conducted during the period of 2008–2010 at the experimental field of the Institute of Forage Crops in Pleven. The hybridization scheme included direct and back crosses...

Cultivars suitable for organic production systems differ in many aspects from those adapted to a conventional one. The present study aimed to evaluate 23 white lupine genotypes for a range of traits: stability, biomass productivity and related parameters, tolerance to Fusarium oxysporum, and nutritional forage value. The goal was to identify white lupine genotypes suitable for organic production conditions in Central Northern Bulgaria. Among the genotypes, Solnechnii, Termis Mestnii, and Tel Keram exhibited the highest dry mass productivity, surpassing 14 t/ha. Solnechnii and Termis Mestnii showed no symptoms of F. oxysporum infection but were unstable in terms of forage yield. On the other hand, the genotypes Bezimenii 1, Barde, 17 Nahrquell, and WAT showed a satisfactory level of stability. Ranking according to basic parameters of biochemical composition, energy, and protein nutritional value determined ranks 1 and 2 for Pink Mutant and Kijewskij Mutant. A genotype with a good balance and complex suitability for organic conditions, considering stability, productivity, and tolerance to F. oxysporum, was identified as Bezimenii 1. This genotype exhibited both stability and productivity while demonstrating high resistance to F. oxysporum (infestation index of 7.18%).

In breeding process of forage pea (Pisum sativum L.) inter variety crosses between two Bulgarian: Pleven 4 (spring form) and Pleven 10 (winter form) and two Russian: Rosacrono (spring form) and Shtambovyi (winter form) varieties are effectuated in field crop experiment during 2011-2013 on the Second experimental field of the IFC, Pleven, Bulgaria. Populations of P 1, P 2, F 2 and F 1 of the crosses Shtambovyi х Pleven 10 and Rosacrono х Pleven 4 are investigated. The aim of this study is to establish the inheritance type of some forage quality parameters as protein, fiber components and digestibility between inter variety hybrids of forage pea. For the hybrids of F1 are estimated changes of heterosis effect. The cross: Shtambovyi х Pleven 10 is characterized with the highest positive real heterosis effect for crude protein content and the cross: Rosacrono х Pleven 4 have the highest rate for crude fiber, Acid-detergent fiber and Aciddetergent lignin. The parameters crude protein and crude fiber for the both crosses are inherited positively over dominantly. Digestibility in vitro dry matter is inherited negatively over dominantly as the qualities of varieties Pleven 10 and Rosacrono are predominated. In the second generation F2 for almost all parameters for Shtambovyi х Pleven 10 a negative depression is estimated. According to the estimated values for the parameter crude protein contents the plants of the two hybrids are depressed most strongly. Because of parameters crude fiber, Neutral-detergent fiber, Acid-detergent fiber and in vitro digestibility of dry matter for the cross Shtambovyi х Pleven 10 a great her percentage of transgressive plants could be anticipated as it counts for crude protein for the cross Rosacrono х Pleven 4. As a result of predominating negative epistatic interaction of cross Shtambovyi х Pleven 10 for crude protein, Neutral-detergent fiber and Aciddetergent lignin a regression of the degree phenotype exhibition of these signs in comparison with the full additive inheritance is anticipated. It is established that there is a high inheritance coefficient in both crosses for the parameters crude protein, crude fiber, Neutral-detergent fiber and in vitro digestibility of dry matter.

This study of a legume’s rhizosphere in tripartite symbiosis focused on the relationships between the symbionts and less on the overall rhizosphere microbiome. We used an experimental model with different garden pea genotypes inoculated with AM fungi (Rhizophagus irregularis and with a mix of AM species) to study their influence on the population levels of main trophic groups of soil microorganisms as well as their structure and functional relationships in the rhizosphere microbial community. The experiments were carried out at two phenological cycles of the plants. Analyzes were performed according to classical methods: microbial population density defined as CUF/g a.d.s. and root colonization rate with AMF (%). We found a proven dominant effect of AMF on the densities of micromycetes and actinomycetes in the direction of reduction, suggesting antagonism, and on ammonifying, phosphate-solubilizing and free-living diazotrophic Azotobacter bacteria in the direction of stimulation, an indicator of mutualistic relationships. We determined that the genotype was decisive for the formation of populations of bacteria immobilizing mineral NH₄⁺-N and bacteria Rhizobium. We reported significant two-way relationships between trophic groups related associated with soil nitrogen and phosphorus ions availability. The preserved proportions between trophic groups in the microbial communities were indicative of structural and functional stability.

Collecting, exploring and using a suitable, genetically diverse source material with different ecological-geographical origin is a determining prerequisite for the breeding success. The present study was conducted during the 2014-2016 period at theInstituteofForage Crops(Pleven,Bulgaria) with 23 cultivars of white lupine originatingPoland,RussiaandUkraine. It was found a significant genetic diversity among the studied cultivars, which was a good prerequisite for starting a breeding program within the crop. The most favorable combination of a high seed productivity and crude protein content had cultivars ‘Tel Keram’, ‘Pflugs Ultra’, ‘WAT’, ‘Solnechnii’ and ‘Pink Mutant’, whose plants were also characterized by a mass of 1,000 seeds between 15 and 21 g. Genetically, the most distant from each other were ‘Bezimenii 1’ and ‘Pflugs Ultra’ compared to ‘Termis Mestnii’ and ‘Solnechnii’ as well as to ‘Tel Keram’. These cultivars are suitable as genitors for the development of high-yielding white lupine cultivars. Studied traits of pod length, number of seeds in a pod and seeds per plant showed a high positive phenotypic and genotypic correlation with the seed productivity in white lupine. Regarding productivity, it can be rely upon the mass of 1,000 seeds, plant height and number of seeds per plant due to their high total effect on the seed weight per plant.

The experimental activity was conducted at the Institute of Forage Crops (Pleven) during the period 2016 – 2018. The adaptive ability of 10 broad bean accessions was determined with respect to main quantitative traits based on parametric and nonparametric analysis. The environment influences to the highest degree the traits of 1 ^st pod height, pods number and seed weight per plant. The plant height and seeds number were strongly influenced by the genotype, and the mass of 100 seeds was determined by the genotype × environment interaction. The broad bean accessions can be distributed as follows: Fb 1929 has a high value of the 1 ^st pod height (34 cm) and is characterized by high plasticity and stability; BGE 029055 and Fb 1896 are stable and form a large number of pods per plant (11 – 15); Fb 1896 and Fb 2486 are distinguished with good adaptability and stability, increased seed weight (28.01 and 30.28 g, respectively) and 100 seeds mass (105.48 g and 91.31 g). Accessions BGE 032012 and Fb 2481 represent a selection value in terms of plant height (61.36 and 65.83 cm); Fb 1929 – in 1 ^st pod height (32.46 cm); and BGE 029055, Fb 1896 and Fb 2486 – in pods number (10.59, 9.67 and 11.89). Fb 1896, Fb 2486 and BGE 041470 can be used to develop a new genetic diversity in breeding aimed at increasing the mass of 100 seeds and seed productivity.