THE RELATIONSHIPS BETWEEN THE CONCENTRATIONS OF INDIVIDUAL AMINO-ACIDS AND PROTEIN IN WHEAT AND BARLEY-GRAIN GROWN AT SELECTED LOCATIONS THROUGHOUT MANITOBA

The concentrations of protein and individual amino acids were determin ed in the grain from three cultivars of wheat and three cultivars of b arley, each grown at 12 locations throughout Manitoba over 3 consecuti ve years. Protein concentration differed (P < 0.05) among the cultivar s of wheat but not (P > 0.05) among cultivars of barley. Although the concentrations of several amino acids differed (P < 0.05) among cultiv ars of wheat or barley the differences among cultivars of each grain w ere not considered to be critical in relation to the requirements for indispensable amino acids for swine or poultry. The percentage of an a mino acid in the DM of wheat and barley increased (P < 0.05) linearly with an increase in percentage of protein in the grain. The wide range of r(2) (0.29 to 0.88) obtained for this amino acid-protein relations hip may be due to the different effect of environment (location and ye ar of growth) on the concentration of individual amino acids, compared to protein, among cultivars of wheat or barley. The percentage of tot al variance due to an interaction between cultivar and environment was low for protein but was several fold higher for individual amino acid s. The error in the prediction of amino acid concentrations with regre ssion equations may be no different than the error associated with pre dicting the mean concentrations of amino acids in the protein of wheat or barley as g (100 g protein)(-1), and obtained from tabulations of analyses. However, regression equations for lysine in wheat and barley did account for the significant (P < 0.05) decrease in concentration of lysine in the protein as the percentage of protein in these grains increased.