The effect of growth regulators for wintering of Ussuri plum seedlings in the conditions of the Angaria region

The purpose of the study was to assess the suitability of growth regulators, such as "Krezacin", "Epin-Extra", "Mival-Agro" as the stimulants to increase the winter hardiness of biennial plants of Ussuri plum in soil and climatic conditions within the Angara Region. Pilot studies were performed in 2009-2012 by carrying out field experiment on the territory of the production nursery of the Educational Botanical Garden FSBEI HPE "Irkutsk State University" (BS ISU). The layout of plants in the plots was 0.9 × 0.2 m. As biological objects for the study annual seedlings of Ussuri plum were taken in the amount of 30 pieces for each stimulator. Plant height measurements were made from the base to the top weekly, from the beginning of the first treatment with growth regulators to the end of vegetation season. The instrumental error made 0.1 cm. The introduction of growth regulators was extra root (7 treatments per a season). In the course of experimental studies the most and least favorable seasonal periods for overwintering Ussuri plum seedlings were identified. The winter conditions of 2009/2010 were extremely severe for overwintering drupaceous trees compared with the long-term and subsequent years of the study Three-years results of the test of the influence of growth regulators on rewintering of biennial seedlings of Ussuri plum were presented. Statistical processing of the measurements of growth indicators was carried out. As a result of the research statistical assessment of the height of seedlings of Ussuri plum upon termination of rewintering depending on processing by physiologically active agents (PAA) during vegetation was carried out. It was established that overwintered plants treated with Сrezacin had had the lowest percentage of freezing of aerial parts (in 2010 - 80.6 ± 2.1; in 2011 - 84.6 ± 1.4; in 2012 - 93.2 ± 1.3 %). A small reliable correlation was established between the degree of damage to plants after wintering and the using growth regulators during vegetation season: rb = 0.4 ± 0.9 ("Crezacin") and rb = 0.6 ± 0.9 ("Mival-Agro"), i. e. the lower the degree of damage to the plant, the higher were stimulating properties of the test substance.