Influence of growth regulators on the formation of main indicators of photosynthetic activity in amaranth (Amaranthus tricolor) varieties

Three year field experiments were carried out at a location with a temperate semi-arid climate condition on the comparative productivity of Amaranth cultivars Kizlyarets (standard variety), Valentina, Iriston on moderately saline meadow-chestnut soils of the Terek-Sulak sub-province of Dagestan, against the background of presowing treatment with growth regulators Albit and Potassium Humate. The studied cultivars provided sufficiently high indicators of the leaf surface area and net productivity of photosynthesis in the variant with the Albit-regulator, 47.6, 49.6 and 51.4 thousand m²/ha and 1.91, 1.97 and 2.01 g/m² per day, respectively. Compared with the control data and the variant with the potassium humate regulator, they increased the productivity of photosynthesis by 2.6, 4.2, 4.0, 0.8, 1.0, 1.4 and 29.9, 31.3, 32.2, 1.0, 1.5, 1.0%, respectively. The maximum data of photosynthetic activity were observed on crops of the Iriston variety. So on an average, according to the variants with growth regulators, the leaf area was at the level of 50.5 thousand m²/ha, with 47.1 and 48.8 thousand m ² /ha in plots with varieties Kizlyarets and Valentina, respectively. The net productivity of the Iriston variety was 1.52 g/m² per day, in the control (non treated), 2.01 g/m ² per day - against the background of the use of the regulator Albit and 1.99 g/m² per day -when treated with the potassium humate regulator. Low values, in the range of 1.47 to 1.91 g/m² per day, were recorded for the standard variety. The data for Valentina occupies an intermediate position. Higher photosynthetic potential was attained by the Iriston variety when the growth regulator Albit was applied.