Studying the biological characteristics of red feather clover (<i>Trifolium rubens</i> L.), as an object of introduction in the conditions of the Volgo-Vyatka region

The article presents the results of a long-term study (2014-2018) of the biological characteristics of growth and development of plants of the introduced species – red feather clover (Trifolium rubens L.) when growing grass stands for seeds in the soil-and-climatic conditions of the Volga-Vyatka region. The species was assessed for winter hardiness, the duration of the growing season, plant height, structure of seed grass stand, seed productivity and seed quality. Winter hardiness of red feather clover in all years of cultivation was high (more than 80 %). The development of plants took place according to the mid-season type: depending on the conditions of the year of growth, they reached the flowering phase for 61-75 days; ripening phase – for 82-105 days from the beginning of regrowth. The duration of grass stand flowering was 14-40 days, ripening – 15-39 days. During the phases of development, the species is responsive to changes in the meteorological conditions of the year of study. In the first and second years of life, the active formation of the root system of plants took place, therefore, taking into account the structure of the seed grass, the height of the plants, the density of the stalk and the proportion of generative stems in the grass, the number of heads and the weight of seeds per 1 m2 was lower than in subsequent years. Productive in seeds grass stand was formed since the third year of life and reached a plant height in the flowering phase of 49.2-56.2 cm, in the ripening phase – 50.4-63.4 cm. It was characterized by the density of the stems standing of 1019.7-1151.6 pcs/m2 with the proportion of generative stems – 96.0-99.6 %, the number of mature heads – 978.9-1147.0 pcs/m2 and seed productivity – 18.8-55.0 g/m2. Seed production was regular, despite strong fluctuations in yield. The seed material was of high quality: seed germination – 94-100 %, germination energy – 58.3-81.3 %, and was characterized by 1000-seed mass of 2.25-2.38 g, hard seed content – 9.1-20.0 %.