Productivity of sugar beet seed plants depending on the quality of mother root crops

In the intensive arable farming the productivity of sugar beets depends on many factors: soil-climatic conditions, introduction of highly productive hybrids, quality pre-sowing seed treatment, use of updated machinery and technologies, fertilizers, reliable plant protection, high technological processing at sugar mills and others. All the mentioned factors can reduce the productivity of sugar beets considerably, but it is not possible to reach a maximum potential of crop productivity without the use of good-quality seeds of the latest hybrids. The quality of sugar beet seeds is formed during the growth, and it depends on several factors, and first of all on the quality of mother root crops – their mass, sizes, turgor, disease damage and others. Laboratory trials were carried out at the Institute of bio-energy crops and sugar beets of Ukraine’s NAAS, field trials were carried out in the conditions of Ivanivka research-breeding station in the years of 2016–2018. The trial scheme envisaged the planting of root crops, which were not damaged with root rot and damaged with root rot, a focal point of rot being removed before planting. During vegetation, seed plants were treated with fungicides at a bud stage (one–time treatment) and at a bud stage and the beginning of flowering (two–time treatment). Fungicides were not used in the control. Mother root crops, seed plants and seeds of a sugar beet hybrid, developed on the basis of cytoplasm male sterility Romul, were the object of the research. In the field trials the following was determined: viability of the root crops (the number of the emerged crops as to the number of the panted root crops) and the seed plant density at a full emergence stage and before harvesting. Agro-biological evaluation of the seed plant condition was made before harvesting – the number of non-productive seed plants (dried, infertile ones and others), the number of disease-damaged plants and the degree of their development. A record plot area of one replication was 20 m2 in field trials, a fourfold replication. The technology of seed plant cultivation is conventional, in accordance with the recommendations of the Institute of bio-energy crops and sugar beets of Ukraine’s NAAS. The paper covered some peculiarities of the yield formation and the quality of sugar beet seeds, depending on the quality of mother root crops. It was proved that the use of the root crops, partially damaged with rot during storage, and even when a focal point of rot was removed before harvesting, had an effect on the root crop viability (which was by 4.4 % lower), the formation of more non-productive plants – by 1.6–1.8 times – due to the increase of prematurely dried plants and infertile ones, which resulted in a serious yield decease – by 0.09-0.13 t/ha and seed quality – viability by 4 % and emergence by 6 %, as compared with the variants where health root crops were planted. Two-time spraying of the seed plants with fungicides resulted in the increase of the yield capacity and the seed quality in the variants where only partially rot-damaged root crops were planted. A tendency to the increase of the mentioned indicators, both in the variants with healthy root crops planted and with partially damaged root crops planted, was recorded under one-time spraying of the seed plants with fungicides. The research of the seeds gathered from the seed plants, which were grown from the root crops, disease-damaged and healthy ones, confirmed the results of the field trials. The viability of the seeds, received from the healthy (not disease-damaged) root crops was higher by 9 %, emergence – by 5 %, as compared with the root crops, partially rot-damaged, focal points of which were removed before planting. Key words: mother root crops, rot, productive seed plants, yield capacity, viability, germination.