Formation of yield components in sugar sorghum as affected by certain components of the cultivation technology

Abstract

Purpose. To study yield components in sugar sorghum hybrids ‘Dovista’ and ‘Tsukrove 1’, varieties ‘Nektarnyi’ and ‘Favoryt’ sown with row spacing of 45 and 70 cm and to determine the crop productivity under the conditions of the Central Forest-Steppe of Ukraine.Methods. Field, visual, measuring and weight, mathematical and statistical.Results. Increasing the number of plants per hectare leads to a decrease in the total sowing density. The plants tiller the best when growing at a row spacing of 70 cm and the density of 150 000 pts/ha: hybrid ‘Tsukrove 1’ had 2 and 3 tillers, varieties ‘Nektarnyi’ and ‘Favoryt’ 2,5 and 2,4 tillers per plant, respectively. The lowest bushiness was in ‘Dovista’ hybrid – 1.7 tillers per plant that can be explained by its genetic features. By increasing the plant density to 250 000 pts/ha, the bushiness decreases by 13% in hybrid ‘Tsukrove 1’ and by 4%, in the varieties, respectively. Maximum indices of leaf coverage (10–12 leaves/plant) were observed in hybrids at the widths between rows of 45 and 70 cm and plant density of 150 000 pts/ha. At the density of 250 000 pts/ha, the number of leaves per plant somewhat reduced. Leaf coverage of sugar sorghum varieties at the row width of 45 cm and the plant density of 150 000–250 000 pts/ha ranged between 8 and 9 leaves per plant. The highest sorghum plants were grown at 45 and 70-cm row spacing and plant density of 150000 pts/ha: in hybrids ‘Dovista’ and ‘Tsukrove 1’ 298–316 cm and 280–297 cm, respectively; in varieties ‘Nektarnyi’ and ‘Favoryt’ 281–310 cm and 292–302 cm, respectively. With an increase in the plant density to 250000 pts/ha plant height decreases by an average of 7–23 cm in hybrids, and by 6–22 cm in varieties. A significant difference in stem diameter as affected by row spacing was not found: it ranged from 1.2 to 2.0 cm in hybrids and from 1.3 to 1.9 cm in varieties. The weight of panicle varied depending on plant density. In hybrids ‘Dovista’ and ‘Tsukrove 1’, at the 70-cm row spacing and plant density 150 000 pts/ha it ranged between 50.2–65.1 g with grain yield of 90.1–90.6%; at 45-cm row spacing the range was 51.0–47.4 g and grain yield 87.7–75.5%, respectively. With the increase in the plant density to 250 000 pts/ha, the weight of panicle and grain yield decreased by 7–14% and 5.7–23%, respectively. The varieties ‘Nektarnyi’ and ‘Favoryt’ showed lower values. In the sowings with 70-cm row spacing and plant density 150 000 pts/ha, the panicles had lower weight ranged from 36.4 to 41.3 g and 85.4–82.3% grain yield. By increasing the plant density to 250 000 pts/ha, these indicators decreased by 3.5–12.4 and 4.9–11.8%, respectively.Conclusions. The most productive was the hybrid ‘Tsukrove 1’ and the varieties ‘Nektarnyi’ and ‘Favoryt’. During the years of research, they formed not only a significant harvest of green mass (‘Tsukrove 1’89.5 t/ha, ‘Nektarnyi’ and ‘Favoryt’80.5 to 86.4 t/has) but also a sufficient yield of seeds, where the percentage of panicles with grain was within 18.2% in the hybrid and 15.9–16.1% in the varieties.