Abstract. The purpose of research is to evaluate Sudan grass cultivars in terms of phenotypic plasticity and yield stability in changing environmental conditions. Research methods. The article presents the data of the research conducted in conditions of the Cis-Ural steppe of the Bashkortostan Republic in 2016–2019. 12 Sudan grass cultivars and hybrid populations, selected in the Bashkir Research Institute of Agriculture, being of varied ripeness, were studied for yielding capacity, stability, and plasticity. Weather conditions in the years of research on temperature and water regimes were different. That made it possible to evaluate the lines in contrasting conditions of cultivation. Results. The most adaptive varieties for forage cultivation were identified: Demskaya variety and populations 285, 318 and 395 with a regression coefficient bi close and equal to one, are characterized as plastic; populations 392, 400, 446/2 are responsive to better growing conditions and characterized as intensive – bi > 1. When cultivated for seeds, population 318 is defined as plastic, while Smena, Demskaya, Chishminskaya rannyaya, Yaktash cultivars, populations 276, 285, 392, 446/2 and 395 are responsive to improved growing conditions and identified as intensive. The best populations according to the comprehensive assessment of varieties for dry matter yield, plasticity and stability are: 400 (yield 69.7 c/ha; plasticity – 1.1; stability – 40.5) and 395 (69.2 c/ha; 1.0; 36.4, respectively). Populations 358 (yield 29.6 c/ha; plasticity – 1.0; stability – 5.2) and 318 (28.1 c/ha; 0.9; 4.2, respectively) were recognized as the best Sudan grass cultivars and populations in terms of seed productivity, plasticity and stability, Scientific novelty. The article collects and presents the materials of many years of the study on Sudan grass phenotypic plasticity and stability.

Inoculation of seeds before sowing of growth-stimulating microorganisms is an effective method for increasing the productivity of crops and forage grasses, in particular. In this work, nine strains of bacteria were tested for their ability to produce the phytohormone indolyl-3-acetic acid (IAA) and stimulate seed germination and elongation of shoots and roots of seedlings of mogar, sudanese grass, awnless brome, alfalfa, and meadow fescue. The highest IAA concentration in the culture liquid was found in the strains Enterobacter ludwigii BLK and Pseudomonas sp. UOM 10 (2001 and 1617 ng/ml, respectively), and the lowest was in Pseudomonas sp. 5GCH and P. koreensis IB-4 (144 and 141 ng/ml, respectively), however, at this stage of research, a direct relationship between the level of phytohormone synthesis and the ability of bacteria to positively affect plant growth was not found. The plants were characterized by the species specificity of the reaction to bacterial treatment, with the exception of the Pseudomonas sp. 5GCH, which in some cases had a positive effect on seed germination, but did not enhance the growth of roots and shoots in the studied herbs. Synchronous stimulation of seed germination and an increase in the length of shoots and roots was observed on mogar plants upon inoculation with E. ludwigii BLK and P. plecoglossicida CH5-2 and on an awnless brome (P. chlororaphis 4CH, B. vietnamiensis 8CH, E. ludwigii BLK, P. laurentiana ANT 17 and P. plecoglossicida CH5-2). None of the strains simultaneously increased the length of shoots and roots in Sudanese grass and meadow fescue, but most microorganisms enhanced seed germination in them. Bacterization did not increase germination in alfalfa, and only Pseudomonas sp. UOM 10 and P. koreensis IB-4 promoted the growth of its shoots and roots.

The current paper has presented the study of productivity, environmental stability and adaptability of 11 Russian grain sorghum varieties of various groups of ripeness in the conditions of the Ural steppe of the Republic of Bashkortostan, conducted in 2015–2019. The purpose of the study was to estimate the grain sorghum varieties according to the parameters of environmental adaptability and stability of productivity in changing environmental conditions. The weather conditions during the years of study were different in temperature and water supply, which made it possible to evaluate the lines in the contrasting cultivation conditions. The index of environmental conditions for grain yield of grain sorghum in 2015 was 0.9, in 2016 it was 1.3, in 2017 it was -1.0, in 2019 it was -1.2. The data completely characterizes the weather conditions of the years of study and their effect on the growth and development of plants. Environmental adaptability (bi) and stability (Ϭ2d) were calculated according to the methods of S.A. Eberchart and W. A. Rassel (1966) interpreted by V. A. Zykin, stress resistance (Ymin–Ymax) was estimated according to the equation of A. A. Rossille, J. Hamblin interpreted by A. A. Goncharenko, productivity range (d) was evaluated according to V. A. Zykin. The varieties ‘Kamelik’, ‘Ogonyok’, ‘Orlovskoe’ turned out to be adaptable (bi was close to 1); the varieties ‘Slavyanka’, ‘Zernyshko’ and ‘Ros’ were responsive to the improvement of growing conditions (bi > 1). Based on a comprehensive estimation of the value of environmental adaptability and stability, the varieties ‘Premiera’, ‘Belochka’, ‘Ogonyok’, ‘Orlovskoe’ were identified as the best ones. These varieties are highly intensive, responsive to the improvement of growing conditions and characterized with high productivity. The paper has collected and presented the material of the long-term study of the environmental adaptability and stability of the grain sorghum productivity in the conditions of the Ural steppe of the Republic of Bashkortostan.

No abstract

Producing high-quality fodder is one of the most urgent priorities in agriculture of the Bashkortostan Republic. The Sudangrass cultivation can address the issue of getting high-quality animal feed in the region. The given paper presents the results of experimental studies on improving the Sudangrass growing technology in the conditions of the Bashkortostan's Cis-Ural steppe, based on the best possible and scientifically proven sowing time, methods and seeding rates. Previous studies have established the way these factors affect the productivity of Sudangrass variety Demskaia. It was found that the Sudangrass variety Demskaia requires a seeding rate of 2.5–3.0 million fertile seeds per 1 ha to realize the productivity potential. The best time for sowing Sudangrass is late May when the soil steadily warms up to +14° - +18°C. The highest crude protein content was observed at earlier sowing with the seeding rate of 2.5-3.0 million fertile seeds per hectare. The higher seeding rate results in the increased leaf area and photosynthetic potential but cuts the net productivity of photosynthesis. The leaf surface area reaches its peak in the "full emergence" phase in the trial with a 15-cm row-width spacing at the seeding rate of 2.5-3.0 million fertile seeds per hectare.