The use of crude protein content to predict concentrations of lysine and methionine in grain harvested from selected cultivars of wheat, barley and triticale grown in the Western Cape region of South Africa
Correlations were determined between the crude protein (CP) and lysine or methionine concentrations of grain from wheat (cultivar: palmiet), barley (cultivar: clipper) and triticale (cultivar: usgen 19) grown in the Western Cape region of South Africa. Twenty samples of varying CP content were collected for each grain type from different areas within the winter-rainfall sub-region. The relationships between CP content (x; percentage on an air-dry basis) and lysine concentration (y; percentage of CP) were as follows: (wheat) y = 6.380 - 0.198 x, (r2 = 0.85); (barley) y = 6.003 - 0.167 x, (r2 = 0.92); (triticale) y = 5.538 - 0.156 x, (r2 = 0.75). The relationships between CP content (x; percentage on an air-dry basis) and methionine concentration (y; percentage of CP) were as follows: (wheat) y = 2.115 - 0.025x, (r2 = 0.39); (barley) y = 1.527 - 0.030x, (r2 = 0.59); (triticale) y = 1.581 - 0.022x, (r2 = 0.31). It was concluded mat the regression equations may be used as a rapid screening method for predicting the lysine and methionine content of South African wheat, barley and triticale grain from CP content.