Еffect of sowing rate on seed productivity of amaranth varieties and mutant lines

Abstract

Purpose. The aim of our study was to determine the effect of different sowing rates on the seed productivity of amaranth varieties and mutant lines, taking into account varietal characteristics and structural elements of the crop. Methods. Six sowing rates (0.2; 0.4; 0.6; 0.8; 1.0; and 1.2 million viable seeds/ha) were tested for two varieties – Kharkiv 1 and Student – and four mutant lines (LMH150, LMH150RV, LMSt150CR, LMSt150CH). Winter wheat was used as the preceding crop. Sowing was carried out in the first decade of May at a depth of 1 cm with 45 cm row spacing. Harvesting was conducted at full seed maturity. Key productivity indicators – seed mass per plant, 1000-seed weight, and plant density – were determined according to DSTU standards. Results. The longest panicles were observed at a density of 1.0–1.2 million seeds/ha, while the optimal sowing rate for forming maximum panicle length was 0.6–0.8 million seeds/ha. The longest panicles were formed by the mutant lines LMH150 and LMSt150CR, and the shortest by the Student variety. Seed mass per plant decreased with increasing sowing density, reaching a maximum at 0.2–0.4 million seeds/ha (up to 34.0 g in Kharkiv 1) and a minimum at 1.2 million seeds/ha (7.7–12.5 g). The 1000-seed weight remained relatively stable (0.75–0.92 g) and was primarily determined by varietal genetic traits. Seed yield largely depended on genotype: the highest yield was observed in Kharkiv 1 (2.5–3.0 t/ha), while the mutant lines LMH150 and LMH150RV yielded 2.25 and 1.7 t/ha, respectively. Conclusions. Seed productivity of amaranth is largely determined by varietal characteristics and to a lesser extent by sowing rate. The highest values were recorded for Kharkiv 1 (2.5–3.0 t/ha, 1000-seed weight 0.86–0.92 g). The mutant line LMH150 also showed high productivity (2.25 t/ha), whereas less productive varieties yielded 1.6–2.05 t/ha.