Phenological traits of red amaranth varieties with a high content of amaranthine cultivated in open fields of Moscow region

The article focuses on phenological features of amaranth varieties grown in open fields as a reaction to variability of weather conditions in the Moscow region. Amaranthine is one of the promising compounds found in red-colored amaranths. It refers to a class of betalain pigments. The study revealed growth stages defined by the highest content of amarantine per plant and analyzed accumulation of the pigment in amaranth leaves and inflorescences. Phenological observations of introduced plant species under new conditions are important and determine their resistance to adverse environmental factors, ability to produce high quality fruits and seeds, and potential for cultivation. During the introduction of new amaranth varieties, the most adapted forms were selected for the conditions of the Non-Chernozem zone of the Russian Federation in 2013-2016. The studied Russian and Ecuador varieties were divided into 4 groups depending on the growth period (from germination to seed maturity). Analysis of phenological traits of plants confirmed that period of amaranth development did not depend on the variety, except the fourth stage of late-ripening cultivars - ‘Don Pedro’ and ‘Eku 17020’, dependent on weather conditions. Being dependent on weather conditions, the vegetative growth period turned to be the most stable. Late cv. ‘Eku 17020’ did not form mature seeds in open ground conditions, which is explained by its origin (Ecuador). In the present study we identified growth stages when plant raw materials had the highest dye content in red-leaved amaranth varieties (‘Valentina’, ‘Don Pedro’ and ‘Fakel’). We also considered the perspective of cultivation of green-leaved varieties with red inflorescences - ‘Pamyati Kovasa’ and ‘Eku-17020’ - as sources of biologically valuable compounds in the Moscow region.