Correction of wheat grain yield for test weight

Abstract

Commercialization of wheat in Brazil takes into consideration two variables: grain yield weight and test weight. The minimum price for the commodity yearly fixed by the Federal Government refers to wheat with standard test weight, fixed at 78 kg. Oscilations in the value of this variable causes the increase or decrease in the value of the minimum price. Wheat research in Southern Brazil has considered these two variables separately, emphasizing the grain yield weight in its decisions and, generally, using the data on test weight as additional Information. This paper suggests that appropriate correction of grain weight related to the test weight be considered in the evaluation of wheat trails results. The suggested procedure uses the method of weighted least squares.