Genotypic differences in the response of spring barley leaf pigment complex to foliar nitrogen application

The purpose of the work is to identify varietal differences in the response of the pigment complex of barley plant leaves to top-dressing with nitrogen-containing preparations. The research was carried out in 2020–2023 in the field experiment on sod-podzolic medium-loamy soil in the conditions of the Kirov region. The effect of nitrogen-containing preparations CAS 28 (N 360 g/l) and Polydon Amino Start (N 130 g/l) on the accumulation of pigments in two upper leaves of plants of ‘Novichok’, ‘Rodnik Prikamya’, and ‘Pamyaty Rodinoy’ cultivars was studied. It was found that foliar treatments with the studied preparations can significantly change the content of green and yellow leaf pigments depending on the growing conditions and specific plant genotype (Chl a – 67–111%; Chl b – 83–118 %; carotenoids – 80–128 % relative to the control without treatment). Of 72 test variants (3 cultivars, 2 treatments, 4 years, 3 types of pigments), changes were noted in 56 variants for the flag leaf, but only in 19 variants for the second leaf. With the significant difference in the nitrogen content of the preparations used, the difference in their effect on the chlorophyll content was only a few percent. So, in 2020 for the ‘Novichok’ cultivar the content of Chl a in a flag leaf increased by 8 % under the use of CAS 28 and by 6 % with Amino Start. In 2022 CAS 28 increased the Chl a content in the flag leaf of the ‘Rodnik Prikamya’ cultivar by 8 %, but Amino Start decreased it by 4 % relative to the control. For ‘Pamyaty Rodinoy’ cultivar in 2020, a negative effect of CAS 28 (-6 % of the control) and a positive effect for Amino Start (+5 % of the control) were noted. The conditions of one and the same year can increase the effect of preparations on the accumulation of pigments for one cultivar, but reduce it for another. In 2020 and 2022 CAS 28 increased the content of Chl a in flag leaves of the cv. ‘Novichok’ (by 8.3–10.4 %) and ‘Rodnik Prikamya’ (by 7.9–9.1 %), but reduced in cv. ‘Pamyaty Rodinoy’ (by 6.2–10.5 %); Amino Start in 2020 increased the content of Chl b in flag leaves of the cv. ‘Novichok’ and ‘Pamyaty Rodinoy’ (by 10.7–11.7 %), but reduced it the cv. ‘Rodnik Prikamya’ (by 9.6 %). In general, the effect of foliar treatment with nitrogen-containing preparations on the content of flag leaf pigments was determined both by the weather conditions of vegetation (from 14.5 to 41.7 %) and by the genotype of the cultivar (from 1.5 to 14.0 %). With regard to the accumulation of photosynthetic pigments for the cv. ‘Novichok’, the use of top-dressing with both preparations is effective (especially in adverse weather conditions at the flowering phase), with CAS 28 for cv. ‘Rodnik Prikamya’, with Amino Start for cv. ‘Pamyaty Rodinoy’.