THE EFFECT OF FOLIAR APPLICATION OF AMINO ACIDS ON THEIR CONTENT AND COMPOSITION IN WINTER WHEAT GRAIN

Field experiments were carried out at the Experimental Station of Vytautas Magnus University (54º52′ N, 23º49′ E) in Lithuania. Winter wheat was grown on the background of N150P90K90 mineral fertilization and was additionally foliar-fertilized with different concentrations of amino acid solutions (0.5-3.0%) at stem elongation and heading stages. The study was aimed to establish protein content as well as quantitative and qualitative distribution of amino acids in winter wheat grain as influenced by fertilization with different concentrations of amino acids. Experimental evidence showed that solutions with different concentrations of amino acids applied at winter wheat stem elongation and heading stages increased grain protein content and total amino acids contents. Plants, fertilized with amino acids solutions at stem elongation stage accumulated higher protein content by on average 4.8%, at heading stage by 4.5% compared with the grain protein content of plants that had not received amino acids fertilization. The total amino acids content in winter wheat grain in response to amino acids applied at stem elongation stage increased by on average 2.0 g kg-1, at heading stage by 5.3 g kg-1. Nonessential and essential amino acids content in winter wheat grain was significantly increased by 2.5 and 3.0% amino acids solutions, applied at stem elongation stage by 0.5, 1.0, 1.5% amino acids solutions applied at heading stage. Winter wheat fertilization with amino acids solutions at stem elongation stage mostly increased the content of glutamic acid, at heading stage mostly increased the contents of glutamic, aspartic, valine, isoleucine, leucine, phenylalanine, methionine, threonine and lysine acids.