||Barley is one of the most important crops in the world agriculture. Ukraine belongs to the largest producers and exporters of grains of this crop. Unfortunately, the low level of yield and strong variation of barley production are typical for our country. Therefore, a great scientific and economic importance has the optimization of the elements of the growing technology of new spring barley varieties, in particular, seeding rates. The reaction to the seeding rates varies among different varieties, which causes the necessity of its specification for a particular genotype.
The seed rates of spring barley cannot be permanent and universal, in each case it is necessary to determine it dependent on variety, soil type, moisture, processing, sowing, etc. Barley has the genetic ability to intensive tillering, and according to this indicator exceeds the other spring crops.
Our studies analyzed plant height, number of productive stems and the yield of spring barley variety Beatrix and variety samples 58/18, 62/18, 66/18 and 70/18 at seeding rates of 6; 5 (control); 4 and 3 million/ha.
The height of spring barley plants is considered to be a biometric indicator. It, like any quantitative indicator, is determined by the genotype and considerably depends on environmental conditions. The plant height of the analyzed varieties of spring barley at a seeding rate of 6 million/ha decreased by 6-11% compared to the control, at 4 and 3 million/ha increased by 4 – 9 and 6 – 9%, respectively.
The number of productive stems is one of the indicators that determines the productivity of sowing. In its turn, it depends on the number of plants and their bushiness. The highest number of productive stems was in the variety of spring barley Beatrix and variety samples 62/18 and 70/18 at a seeding rate of 6 million/ha, and selective numbers 58/18 and 66/18 – at 5 million/ha.
At extreme seeding rates (of 3 and 6 million/ha) in the experiment, the yield of the analyzed selective numbers of spring barley was significantly inferior to the control (5 million/ha). There was no significant difference between the yield of Beatrix varieties and 58/18, 62/18 and 70/18 varieties while cultivation at 4 and 5 million/ha.
Changes in seeding rates differently influenced the manifestation of different indicators of selective numbers of spring barley. Thus, the variety sample 58/18 turned out to be highly flexible in plant height and yield, while the number of productive stems — low flexible. Selective number 62/18 was characterized by high flexibility of plant height and number of productive stems, and average yield. The variety sample 66/18 was low flexible at all indicators.