Features of formation of grain sorghum yield structure elements in dependence on inter-row spacing and fertilizing

Purpose. Reveal varietal features of formation grain sorghum yield structure elements depending on inter-row spacing and fertilizing doses of nitrogen fertilizers. Methods. Laboratory, field, statistical. Results. Data on features of structural elements formation and productivity of grain sorghum in dependence on varietal characteristics, inter-row spacing and level of mineral nutrition are presen­ted. An important indicator for plant productivity formation is productive tillering, since grain sorghum, like most cereals, has the ability to tiller, which under favourable conditions allows forming up to 25–45% of yield on the side shoots. In our case, sowing of grain sorghum with sowing rate 190 thousand pcs./ha and inter-row spacing 35, 50 and 70 cm, respectively, we got the same plant nutrition area – 526 cm2; the distance between plants in the row is 15, 10.5 and 7.5 cm, respectively. The average number of grains per panicle in the sorghum hybrid ‘Lan 59’ according to the experiment was 866.9 grains, but the maximum values were observed with inter-row spacing 70 cm and fertilizers N60P60K60 + N40 – 1035.1 pcs. In hybrid ‘Brigga F1’, on the average in the experiment was 554.3 pcs. grains/panicle, and with inter-row spacing 70 cm and fertilizing by nitrogen fertilizers N20–60, respectively 595.7 – 602.4 pcs. We obtained similar indicators in hybrid ‘Burggo F1’ and fertilizing rate N60P60K60 + N40 – 961.7, but on average, in the experiment, the hybrid formed 858.6 pcs. grains/panicle. Mass of grain from one plant allows fully evaluate individual productivity of plants of studied hybrids. The best indicators of grain mass per plant were obtained with inter-row spacing 50 cm and fertilizing rates N60P60K60 + N60. So, on average, in the experiment in hybrid ‘Lan 59’, 41.2 g of seeds were formed per one plant, in the hybrid ‘Brigga F1’ – 63.4 g, in the hybrid ‘Burggo F1’ – 64.0 g. The best weight parameters of 1000 seeds were obtained with the inter-row spacing 50 cm and fertilizing rates N60P60K60 + N60, that is, ‘Lan 59’ – 37.3 g, ‘Brigga F1’ – 37.4 g, ‘Burggo F1’ – 30.2 g. Conclusions. Changes in inter-row spacing and level of mine­ral nutrition cause variability in formation of yield structural components of grain sorghum hybrids – productive tillering, number of panicles per hectare, number of grains per panicle, mass of grain per plant, mass of grain per panicle and mass of 1000 seeds, which determine individual productivity of plants.