Dependence of pigment content in meadow clover leaves on soil phosphorus level

In 2018-2019, the effect of different levels of soil phosphorus on the pigment complex of the clover (Trifolium pratense L.) leaves was assessed. Total chlorophyll content was 15.34-19.05 and 11.47-14.10 mg g- 1 dry matter, of which Chl a accounted for 9.64-11.36 and 6.67-7.98 mg g-1 (2018 and 2019 respectively). Carotenoids content varied within 2.69-3.12 and 1.52-1.88 mg g-1 in 2018 and 2019 respectively. Weight ratio of total chlorophyll/carotinoids (5.7-6.7 in 2018 and 6.8-9.6 in 2019) gives the grounds to consider that there was not disorders in structure of the pigment complexes of leaves in both year. There were statistically significant linkage of level of soil phosphorus with Chl a (r = 0.536-0.743) and Chl b (r = 0.725-0.748) in cooler conditions of 2019. In wormer 2018, these links were insignificant (Chl a = -0.146 to -0.286 and Chl b = -0.257 to -0.275). Correlation between phosphorus content in soil and carotenoids content in leaves was insignificant in all cases. Chl pigments showed a polynomial second order relationship with level of soil phosphorus. In 2019, these relations was statistically significant at p ≤ 0.05 (R2 = 0.68-0.76) for both chlorophylls. Under conditions of 2018 these relations was insignificant (R2 = 0.10-0.43).</jats:p

Dependence of pigment content in meadow clover leaves on soil phosphorus level

In 2018-2019, the effect of different levels of soil phosphorus on the pigment complex of the clover (Trifolium pratense L.) leaves was assessed. Total chlorophyll content was 15.34-19.05 and 11.47-14.10 mg g- 1 dry matter, of which Chl a accounted for 9.64-11.36 and 6.67-7.98 mg g-1 (2018 and 2019 respectively). Carotenoids content varied within 2.69-3.12 and 1.52-1.88 mg g-1 in 2018 and 2019 respectively. Weight ratio of total chlorophyll/carotinoids (5.7-6.7 in 2018 and 6.8-9.6 in 2019) gives the grounds to consider that there was not disorders in structure of the pigment complexes of leaves in both year. There were statistically significant linkage of level of soil phosphorus with Chl a (r = 0.536-0.743) and Chl b (r = 0.725-0.748) in cooler conditions of 2019. In wormer 2018, these links were insignificant (Chl a = -0.146 to -0.286 and Chl b = -0.257 to -0.275). Correlation between phosphorus content in soil and carotenoids content in leaves was insignificant in all cases. Chl pigments showed a polynomial second order relationship with level of soil phosphorus. In 2019, these relations was statistically significant at p ≤ 0.05 (R2 = 0.68-0.76) for both chlorophylls. Under conditions of 2018 these relations was insignificant (R2 = 0.10-0.43)

Genotypic differences in reaction of barley root system on Mn and Fe toxicity

The study was performed to determine genotypic differences in spring barley cultivars on resistance to 1.1 mM manganese and 1.2 mM iron at early stage of growth. Resistance level was estimated by morphologic (root length) and physiological (level of antioxidant activity, accumulation coefficient) parameters. Morphologic trait was less sensitive for cultivar differentiation in compare with physiological one. Based on relative root length index all cultivars were classified as resistant having resistance index about 80-94% for Mn and 67-76% for Fe. Reaction to Mn by change in antioxidant activity was uniform: it was increased from 4% in cv. Bionic up to 28% in cv. Farmer. According to reactions to Fe, studied cultivars were divided into three groups: high resistant (cv. Belgorodsky 100 and Farmer; increase in antioxidant activity 2 and 18% accordingly), weak resistant (cv. Forward, Bionic, and 29-11; changes were insignificant) and sensitive one (cv. 346-09; 8%-decrease in activity). For manganese accumulation coefficient is higher than for iron. The maximum accumulation coefficient for manganese was characteristic of cv. 29-11 (190), for iron - cv. Bionic (120). The genotypic specificity for root antioxidant activity can be used as a rapid test of resistance to manganese or iron in initial breeding material

Genotypic differences in reaction of barley root system on Mn and Fe toxicity

The study was performed to determine genotypic differences in spring barley cultivars on resistance to 1.1 mM manganese and 1.2 mM iron at early stage of growth. Resistance level was estimated by morphologic (root length) and physiological (level of antioxidant activity, accumulation coefficient) parameters. Morphologic trait was less sensitive for cultivar differentiation in compare with physiological one. Based on relative root length index all cultivars were classified as resistant having resistance index about 80-94% for Mn and 67-76% for Fe. Reaction to Mn by change in antioxidant activity was uniform: it was increased from 4% in cv. Bionic up to 28% in cv. Farmer. According to reactions to Fe, studied cultivars were divided into three groups: high resistant (cv. Belgorodsky 100 and Farmer; increase in antioxidant activity 2 and 18% accordingly), weak resistant (cv. Forward, Bionic, and 29-11; changes were insignificant) and sensitive one (cv. 346-09; 8%-decrease in activity). For manganese accumulation coefficient is higher than for iron. The maximum accumulation coefficient for manganese was characteristic of cv. 29-11 (190), for iron - cv. Bionic (120). The genotypic specificity for root antioxidant activity can be used as a rapid test of resistance to manganese or iron in initial breeding material.</jats:p

EFFECT OF TIMING AND DOSAGE OF “KAS 28” APPLICATION ON OAT PLANTS DEVELOPMENT

To determine the optimal options for using fertilizer “KAS 28” when growing hulled (covered) oat cv. ‘Kirovsky 2’, the following options were investigated: 1 – control (no fertilizer); 2 – “KAS 28” in the recommended dose (35 l/ha) at the tillering stage; 3 – crops treatment with “KAS 28” – 60 % of the recommended dose (21 l/ha) at the tillering stage; 4 – “KAS 28” in the recommended dose at the beginning of stem elongation stage; 5 – crops treatment with “KAS 28” – 60% of the recommended dose at the beginning of stem elongation stage. The studies were carried out in 2019-2020. Over the year of research, the average yield varied from 5.52 t/ha in option 3 (at control level) to 6.59 t/ha in option 5 (16.0 % over control). Variants 2 and 4 exceeded control by 0.49 and 0.50 t/ha (8.8 %), respectively. Treatment with a reduced dose of fertilizer in the tillering stage reduced yield by 0.65 t/ha (10.6 %), at the beginning of stem elongation stage, on the contrary, increased it by 0.41 t/ha (6.6 %). “KAS 28” application led to an increase in the panicle length by 3.5–5.3 % compared to control (16.9 cm), the number of grains per panicle by 5.3-12.0 % (48 pcs in the control variant), the grain weight per panicle by 5.6-23.4 % (control – 1.78 g). Generally, the application of a reduced dose of fertilizer was less efficient. However, fertilizer dose decrease led to a statistically significant increase in 1000-grain weight indicator (by 0.55–1.61 g or 1.4–4.1 %). To increase the yield of oat cv. ‘Kirovsky 2’ and reduce the anthropogenic load on the agroecosystem, we offer to carry out topdressing at the stem elongation stage with the fertilizer “KAS 28” at a dose of 21 l/ha.</jats:p