The yield of amaranth depending on the variety and sowing rate in conditions of sufficient moisture

Abstract

In order to establish the optimal sowing rate of amaranth varieties in conditions of sufficient moisture, field studies were conducted on dark-gray podzolized soil. The weather conditions during the research years were quite contrasting and differed from the average multi-year data both in the amount of precipitation and in terms of temperature. Hydrothermal conditions differed from the average long-term data. It was warmer and more rain fell. In 2020 and 2022, the average temperature during the growing season was 15.3 °C, which is 0.5 °C higher than the long-term data. In 2021, it (14.8 °С) corresponded to the average long-term data. In 2020, 129 mm more fell during the growing season, in 2021 – 73 mm more, in 2022 – 28 mm more than normal. Six sowing rates were studied: 0.2; 0.4; 0.6; 0.8; 1.0; 1.2 million similar seeds per hectare for six varieties Kharkivskyi 1, Aztec, Lera, Sem, Studentskyi, Ultra.

The research established that the density of plants depended little on the variety and was within 25‒28 plants/m². Seeding rate had a significantly greater effect on plant density before harvest. At the sowing rate of 0.2 million/ha, it was
14 plants/m², and at the sowing rate of 1.2 million/ha, it increased only to
32 plants/m², or by 18 plants/m². Among the varieties of amaranth, the Kharkivskyi 1 was characterized by the highest individual productivity (12.5‒34.0 g) at all sowing rates. The mass of seeds per plant was the highest (17.6‒34.0 g) in all varieties at the sowing rates of 0.2 million/ha. The optimal combination of elements of the crop structure for the formation of the highest productivity in the variety Kharkivskyi 1 was 20 plants/m² and the weight of seeds per plant was 23.1 g. With the same density of plants and a slightly lower weight of seeds per plant (19.7 g), the highest yield was obtained in Lera variety. The highest weight of 1.000 amaranth seeds was in the most productive variety Kharkivskyi 1, which, depending on the sowing rate, varied between 0.86 and 0.92 g. It changed more under the influence of the variety (0.14 g) than under the influence of the sowing rate (0.04 g). An increase in the seeding rate to 1.2 million/ha led to a decrease in the weight of 1.000 seeds to 0.79 g, while at a seeding rate of 0.2 million/ha it was 0.83 g. The highest yield on average over three years was obtained in amaranth variety Kharkivsky 1 with a sowing rate of 0.4 million/ha ‒ 4.63 t/ha. the lowest yield on average over three years, according to sowing rates, was in amaranth of the Ultra variety. Aztec and Studentskyi varieties provided an increase in yield compared to Ultra, respectively by 0.21 t/ha (8.0 %) and 0.41 t/ha (15.5 %). In the Sem variety, the yield increase was 0.82 t/ha (31.1 %). Varieties Kharkivskyi 1 and Lera prevailed over the Ultra variety by 1.76 t/ha (66.7 %) and 1.13 t/ha (42.8 %), respectively.

The lowest yield on average for all studied varieties was at the maximum sowing rate. On the option with sowing 1.0 million/ha, the yield increased to
3.35 t/ha, which is higher than the norm of sowing 1.2 million/ha by 0.11 t/ha
(3.4 %). At the sowing rate of 0.8 million/ha, the yield increased by 0.19 t/ha
(5.7 %). The largest increase was obtained for sowing rates of 0.6 million/ha ‒
0.22 t/ha (6.8 %). The optimal sowing rates for amaranth varieties are as follows: Kharkivskyi 1, Lera and Studentskyi ‒ 0.4‒0.6 million/ha, Sem variety ‒ 0.6‒0.8, Aztec variety ‒ 0.6‒1.0, Ultra variety ‒ 0.8‒1.2 million/ha.