Productivity of stevia agrophytocensosis depending of variety

Abstract

Introduction. In Ukraine, stevia is a relatively new culture - it was introduced in 1984 in the form of a narrow genetic source. The first introduced stevia genotypes in Ukraine were diploids [4]. Meanwhile, the success of growing stevia, as well as other crops, depend primarily on the variety as the most important factor in the intensification of crop production. The origins of this role of the variety are in the very nature of the formation of plant productivity, which is based on the genetically determined and realized by its phenotype its ability to vary degrees of completeness and efficiency of accumulation of organic substances from carbon dioxide of air, water, elements of mineral nutrition due to solar energy.

The main requirements for stevia varieties are: high yields of raw and dry leaves, the content of dry matter in the leaves, the accumulation of diterpenic glycosides in them and their qualitative composition, plant resistance to pests and diseases, and high ecological plasticity [4].

The purpose of research. Methods of creating high-yield stevia varieties with high content of diterpenic glycosides and their ecological evaluation depending on the growing zone.

Materials and methods of research. In order to expand the gene pool of stevia and obtain valuable for selection and source genetics, methods of polyploidy (colchification in culture in vitro) were used, resulting in polyploid forms with a double set of chromosomes (4n = 36). The method of hybridization allows growing of immature embryos in a culture of in vitro complete plants and, at free pollination, to obtain in a sufficient number of different combinations with certain valuable properties [1].

The method of induced morphogenesis [2] was used to obtain samoclonal variants of stevia and to expand its genetic variability. The obtained regenerate plants multiplied microcologically and received microclonal lines, which, after adaptation in the open ground, were tested in field conditions. During vegetation of plants were determined: resistance of plants-regenerants to diseases, the intensity of growth of leaf mass, the content of synthetic pigments and diterpenovyh glycosides.

The Institute for Bioenergetic Cultures and Sugar Beetroots also used methods of experimental mutagenesis by selecting the most effective selections of mutagens (nitrosomethyl urea), their concentrations (0.04%), the specifics of their application in culture in vitro, and the method of non-traditional selection - isolation and cultivation of protoplast and regeneration of these plants [3].

Research results. As a result of selection work at the Institute for Bioenergetic Cultures and Sugar Beet, for the first time in Ukraine, two varieties of stevia were created: "Bereginya" and "Slavutich", which were entered in the Register of Plant Varieties of Ukraine in 1999 and were more productive than the original forms [4] . In the "Bereginya" variety, the yield of raw leaflets was 24,80 t / ha, dry weight - 2,36 t / ha, the content of steviosidium - 7,2%, in the Slavutich variety 21,5 and 2,06 t / ha respectively and 6.6%, which is much higher than control (Table 1).

High levels of raw mass and dry leaves and the content of diterpenic glycosides were noted in tetraploid and hybrid genotypes, as well as "cosmic" numbers (see Table 1). Analyzing the results obtained, it can be stated that, for most of the studied indicators, some of the numbers deserve further attention and the continuation with them of breeding work.

As a result of the continued breeding work with prospective numbers at the Institute of Bioenergetic Cultures and Sugar Beetroot, three varieties of stevia "Galina", "Marina" and "Katerina", which were entered in the Register of Plants of Ukraine in 2017, were created. We give a brief biomechanical description of the varieties of stevia of the new generation.

The variety "Galina" - the state registration number - 171053 dated May 31, 2017. The variety created as a result of the control cross with the parent form Slavutich breeds vegetatively (cuttings, in vitro, Cloning) and is suitable for cultivation in the Polissya, Forest-Steppe, Steppe and in the open ground. The yield of the green mass is 35 t / ha, plant height 110 cm, vegetation period 110 days, 1000 seeds - 0,21 g, perenosporosom damage - absent, stevioside content - 21,0% [5].

The variety "Marina" - the state registration number - 171054 dated May 31, 2017. The grade is created as a result of controlled crossing with the parental form "Bereginya", vegetatively propagated (cuttings, in vitro, Cloning) and is suitable for cultivation in the zone of Polissya, forest steppe, steppe . The yield of the pretreated mass is 40 t / ha, plant height is 105 cm, vegetation period 115 days, weight 1000 seed - 0,24 g, lesion of the perenosporozom - absent