Bulgarian varieties of perennial forage grasses developed at the Institute of Forage crops Pleven

Aneliya Katova

Abstract: To obtain sustainable agriculture and adaptive forage production, it is necessary to develop new varieties of forage crops, combining high productivity and ecological stability. The indirect benefit of genetic improvement from plant breeding is substantial through yield and quality improvements and increased resilience to changing climatic conditions. Plant breeding is a particularly dynamic and research intensive activity with long lag times between investment and returns, which emerge in the form of varietal seed stock with particular traits or characteristics that are attractive to Bulgarian cropping and forage producers. Commercial plant breeding follows a number of stages and producing a marketable variety can be the product of 20 years development. Perennial grass breeding in Bulgaria has now a strong 56 year-long tradition, especially in the Institute of Forage Crops in Pleven. The objective of breeding program was to develop new perennial grass varieties with high forage and seed productivity, high forage quality and high adaptive potential for pasture, hay and landscape improvement use. A great amount of initial breeding materials (local native populations and introduced varieties) of perennial forage grasses of cool and warm climate was collected and studied in the Institute of Forage Crops, Pleven during the period 1966–2022. Biodiversity of new plant forms and varieties was developed by complex applying conventional and modern breeding methods – purposeful efficient selection by productivity and adaptivity, ecologogenetic analysis of quantitative traits, polyploidization, hybridization, including interspecific one. The ploidy level was determined in the Institute of Genetics and Breeding, Melle, Belgium in 2007. The samples were analyzed by Partec Cell Analyzer CA–II and software DPAC (Münster, Germany). The intensity of fluorescent emission correlated linearly with DNA quantity. The results were obtained as histograms. During these years eight varieties of 6 perennial grass species were developed as follows: cocksfoot (Dactylis glomerata L.) Dabrava – tetraploid, smooth brome, (Bromus inermis Leyss.) Nika – octoploid, tall fescue (Festuca arundinacea Schreb.) Albena – hexaploid, perennial ryegrass (Lolium perenne L.) IFK Harmoniya – dipolid, Tetrany and Tetramis – tetraploids, crested wheatgrass (Agropyron cristatum Gaerth.) Svejina – diploid and standard wheatgrass (Agropyron desertorum (Fich.) Schultes.) Morava – tetraploid. Variety description was made according CPVO (2011, 2015, 2021) and UPOV (2006) technical guidelines for different species. The perennial grass varieties have valuable characteristics, such as high forage and seed productivity, persistency, stress tolerance, forage quality, different direction of use (hay, pasture, silage, erosion control, amenity, phytoremediation of polluted urban soils), different ploidy level and earliness. In last years study they confirmed useful characteristics and stability. They are registered on the National List, and entered on the EU Common Catalogue and becomes freely marketable across the EU, and also in OECD list. The Institute of Forage Crops maintains the registered varieties and produces Breeder’s, Prebasic and Basic seeds. Original seed samples from each perennial grass variety are presented and entered long storage at the Bulgarian National Plant Genetic Bank in Sadovo.

Keywords: Bulgarian varieties; forage quality; forage yield; perennial grasses; ploidy level

Date published: 2023-10-23