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Perennial grasses have got greater attention in the past decade due to their potential to be productive over several years and their positive impacts on the environment. A great resource in this regard are the native species, which are well adapted to the specific conditions of the environment, but are often underestimated and irrationally used. The objects of study in the present research were 8 grasses (Festuca rubra, Lolium perenne, Dactilis glomerata, Arrhenatherum elatius, Festuca arundinacea, Briza maxima, Trisetum flavescens, Agrostis alba), typical for the Middle Balkan Mountains region, in order to assess their productivity and stability. The two-factor analysis of variance in terms of dry mass yield revealed significant influence of the factors of species, environment, and their interaction. During the 9-year experimental period, the highest yield was demonstrated by F. rubra (5.75 t ha-1), followed by F. arundinacea (5.54 t ha-1) and A. elatius (5.43 t ha-1). The stability parameters, calculated by the methods of regression analysis defined as stable the species of A. elatius and A. alba, and those, calculated by variance and non-parametric analyzes - F. rubra, D. glomerata and F. arundinacea. Differences in the stability assessment of the individual parameters are due to the fact that the different methods are based on different concepts of stability. The GGE biplot analysis, which integratedly assesses the species for their productivity and stability, identified F. arundinacea and A. elatius as the most favorable combining of these indicators. Trisetum flavescens was also characterized by good stability and average productivity. These species are suitable for cultivation in a wide range of environmental conditions. [ABSTRACT FROM AUTHOR]

During the period of 2016-2019 in the experimental field at Research Institute of Mountain Stockbreeding and Agriculture - Troyan was conducted a field experiment. It was traced the adaptability and productivity on perennial forage grasses (Lolium perenne L. - cv. K-11; Lolium multiflorum L. - cv. K-13; Lolium multiflorum L. - cv. K-29t; Festuca arundinaceae Scherb. - cv. K-20; Festuca pratensis Huds. - cv. K-21; Dactylis glomerata L. - cv. K-24 and Bromus inermis Leyss - cv. BV-1 exp.) in the conditions of the Central Balkan Mountain, Bulgaria. The highest average fresh mass productivity in the first (1740.7 kg/da) and second (629.6 kg/da) regrowth, and the highest average dry mass yield in the second regrowth (226.7 kg/da) were found in tall fescue (cv. K-20). Smooth brome (cv. BV-1exp.) achieves maximum yield of dry mass in the first regrowth (487.8 kg/da). Compared to the other types of forage grasses included in the experiment, the Italian ryegrass (cv. K-29t) gave (P <0.05 - P <0.001) the highest grass cover in spring (84.1 cm) and summer (59.8 cm) regrowths. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine and compare the sensitivity of new high yield Bulgarian varieties of perennial ryegrass (Lolium perenne L.) - Harmoniya, Tetrany and Tetramis to glyphosate in laboratory conditions. The effect of three doses of glyphosate - 360, 720 and 1440 g a.i./ha applied in the growth stage tillering (BBCH - 22-23) on perennial ryegrass on the dynamics of plant growth and formed fresh biomass in g per plant was studied. Genotypic differences were observed between the studied varieties of perennial ryegrass to glyphosate. With a relatively high sensitivity to glyphosate conditionally can be determined diploid variety Harmoniya in which the depression coefficients (B) on the dynamics of growth and accumulation of fresh biomass are in the range from -5.7 to - 4.7, while for tetraploids Tetrany (B) (average) is in the range of -3.3 to -3.9 and for Tetramis (B) (average) is within limits from -3.2 to -3.9, they have relatively high tolerance to glyphosate and can be used as components in future programs. [ABSTRACT FROM AUTHOR]

During the period 2014-2016 on the experimental field of the Institute of Forage Crops - Pleven a study was conducted with the purpose to determine the selectivity of some herbicides to Bulgarian variety of perennial ryegrass (Lolium perenne L.) IFK Harmoniya during stand establishment and seed production. It was found that herbicides Accurate 60 WG (600 g/kg of metsulfuron-methyl) - 10 g/ha, Ally Max (143 g/kg tribenuron methyl + 143 g/kg metsulfuron methyl) - 35 g/ha and Eagle 75 WG (750 g/kg chlorsulfuron) - 20 g/ha showed high selectivity to perennial ryegrass (Lolium perenne L.) and can be applied at the growth stage BBCH 12-14 on the crop, during establishing year of the stand for control of broadleaf weeds. Accurate 60 WG - 10g/ha and Ally Max - 35 g/ha applied at the growth stage (BBCH 28-30) in the year of seed production had a high selectivity to perennial ryegrass and can be applied for control of broadleaf weeds. Applied low dose of Axial One (45 g/l pinoxadene + 5 g/l florasulam) - 350 ml/ha had hormesis effect to perennial ryegrass and can be used for stimulation the accumulation of fresh and dry biomass during the year of stand establishment and, as well as in the years of seed formation. The herbicide tolerance of perennial ryegrass to key herbicides with complex action (for weed control against annual monocotyledonous and dicotyledonous weeds) has been determined, which could serve as a means of increasing the efficiency of the breeding process. [ABSTRACT FROM AUTHOR]

The aim of the study is to determine the variability of morphological characters for the vegetative development of perennial ryegrass collection and to make a selection of genotypes for different directions of use - for fodder and ornamental purposes. During the period 2015-2018 in the Institute of Forage crops - Pleven a collection nursery was studied in fi eld non-irrigated conditions on leached black soil, in block method, in 2 replications of a total of 21 accessions of perennial ryegrass, with 50 individual plants each (15 varieties and 6 ecotypes, 11 tetraploid and 10 diploid, from Bulgaria, Belgium, Romania and China). Mean, minimum, maximum values, standard deviations and variation coefficients for plant height, tuft width at base and top, habitus, number of leaves, leaf length and width, stem thickness, stem number were present. A great genetic diversity was found in the morphological features of the perennial ryegrass collection accessions, both between them and within population. Highest values of variation coefficients (CV) were obtained for plant stems - 43.05%, habitus - 33.85%, leaf length and width - 25.43% and 26.16%, respectively. In the collection the tetraploid varieties have higher plants, longer and broader leaves and more upright habitus, which ensures higher productivity of fodder and for ornamental and amenity purposes are suitable diploid varieties and ecotypes, with lower plants, short and narrow leaves. [ABSTRACT FROM AUTHOR]