Sources of Variation for Long‐Flow Experimental Milling

Flour milling quality of new wheat cultivars routinely is measured on long‐flow experimental flour mills with multiple break and reduction rolls that produce many mill streams. Virginia State wheat trials were evaluated to determine the relative contributions of genotypes, production years, and error to the variation in long‐flow milling traits using the Allis‐Chalmers long‐flow flour mill at the USDA Soft Wheat Quality Laboratory. In one study, 11 cultivars were evaluated for five years. Variation due to error, which was based on the cultivar × year interactions, was half the size of genotypic variance for straight‐grade and break‐flour yield. In the second study, 27 cultivars were evaluated for two years. Genotype was a more important source of variance for milling traits than error. Error variances were approximately one‐half of the genotype variances for straight‐grade flour yield and break‐flour yield. One paired evaluation between an experimental line and a standard cultivar may be sufficient to detect large differences in milling performance between an experimental and a check cultivar. However other milling and flour characteristics tended to have smaller ratios of genotype to error variance, suggesting that greater levels of replication may be required than for straight‐grade flour yield.