The objective of this study was to evaluate the influence of two organic nanofertilizers, Lithovit and Nagro, on in vitro germination, pollen tube elongation and pollen grain viability of Pisum sativum L cv. Pleven 4. The effect of their application was high and exceeded data for the untreated control (44.2 and 47.23 % regarding pollen germination and pollen tube elongation, respectively), as well as the effect of the control organic algal fertilizer Biofa (17.5 and 27.9 %, respectively). Pollen grains were inoculated in four culture media. A medium containing 15% sucrose and 1% agar had the most stimulating impact on pea pollen grains. Pollen viability, evaluated by staining with 1% carmine, was within limits of 74.72-87.97%. The highest viability of pollen grains was demonstrated after the application of Nagro organic nano-fertlizer.

The choice of appropriate cultivars is crucial for a well-functioning system in organic farming. Based on a three-year study (2012–2014) and comprehensive assessments of five cultivars (Pleven 4, Glyans, Svit, Kamerton, Modus) of forage pea, it was concluded that Pleven 4 showed the complex of features that defined it as suitable for growing in organic farming conditions. This cultivar was distinguished by a greater height, total biomass, average daily growth rate; parameters that provide good competitiveness against weeds as well as uptake and use of nutrients. In addition, Pleven 4 had a high yield of fodder (4050.7 kg ha⁻¹) combined with an average ecological stability (bi = 0.93), medium resistance to downy mildew (mean disease score = 2.7) and a high nitrogen content of the forage biomass (31.8 g kg⁻¹ dm). Kamerton also showed to have good qualities for most of the above-mentioned characteristics, but this cultivar was found to be ecologically unstable and moderately sensitive to downy mildew. Modus could be used as a donor for resistance to downy mildew.

OPTIMAL PARAMETERS OF MODEL BROAD BEAN CULTIVAR FOR THE CENTRAL PART OF THE DANUBE PLAIN, BULGARIA N. Georgieva, V. Kosev

During the period 2012 -2014 was conducted a field trial with seven vetch cultivars: six Moldavian cultivars Liya, Lorina, Vilena, Moldovskaya (belonging to Vicia sativa L.), Violeta and Viola (belonging to Vicia villosa Roth.) and one Bulgarian cultivar Obrazets 666 (belonging to Vicia sativa L.). The performance, adaptability and stability of the tested cultivars were determined in relation to plant height (cm), stem (mm) and length (cm) of the pod, number seeds and pods per plant, number seeds per pod, 1000 seed weight (g), seed weight per plant (g) and seed yield (kg da-1). Traits such as plant height, pods per plant, seeds per plant, 1000 seed weight and seed yield showed a significant genotype × environment interaction which shows the participation of different gene systems in their control. In regard of these traits were calculated parameters of phenotypic stability and selection-valuable genotypes were determined. The cultivar Moldovskaya could be considered close to the ideal type (bi ≈ 1.0), suitable for growing over a wide range of environment. Liya and Obrazets 666 were determined as unstable (bi > 1) but with good responsiveness, providing them high yields at moderate environmental conditions. Cultivars Liya and Obrazets 666 could be defined as stable and with good responsiveness (bi = 1.07 - 1.11), but because of lower yields they do not have priority over others. From viewpoint of selection, cultivars Moldovskaya, Liya and Obrazets 666 are suitable for including in breeding programmes and developing new vetch lines with high and stable yields