Een onderzoek naar variabiliteit en vererving van het ruw-eiwitgehalte in Engels raaigras

Raising the protein content by breeding of grasses forms a contribution to raising grass quality (in which digestible protein is a valuable nutrient).

A strong correlation proved to exist between time of heading and chemical composition. Protein content as a qualitative property was much influenced by environmental conditions.

A theory of Schwarze and Schwanitz based on physiological considerations existed that selection for higher protein content, combined with high protein yield, should be performed only under such environmental conditions that this combination is physiologically possible.

Genetic differences in protein content among plants with the same physiological rhythm were found. These differences showed a clear interaction with environment. They were heritable. The reaction of genotype on environment was also heritable. Phenotypic variability of a certain genotype was enormous. It many times exceeded differences between genotypes, even if these were extremes. Behind the phenotypic negative correlation between protein and carbohydrates there seemed to be a negative genotypic correlation.

Many protein rich genotypes were less productive and less vigorous.

Cumulative selection was not hopeful.

The theory of Schwarze and Schwanitz based on the theoretical physiological observation tested here did not hold.