Crop residues are utilized as lignocellulosic biomass for production of energy via biochemical or thermochemical degradation. The conversion efficiency depends on the content of major organic components, but also other elements play a role and are thus considered to be important biomass quality parameters. In the present study, 20 winter wheat (Triticum aestivum L.) genotypes were grown at two different geographical locations and the straw was analyzed for the concentration of elements such as silicon (Si), sulfur (S), nitrogen (N) and the metals potassium (K), calcium (Ca) and magnesium (Mg). The Si concentration ranged between 11.3 g kg−1 and 23.4 g kg−1 straw dry matter and differed significantly among the genotypes and between the locations. Significant differences among genotypes were also observed for S, K and Ca, but not for N. The enzymatic saccharification efficiency differed significantly among the genotypes. Straw concentration of Si did not influence the sugar release during enzymatic saccharification, while total carbon (C) had a positive influence and S and K a negative effect. It is concluded that the quality of straw biomass for bioenergy purposes can be optimized by proper selection of genotype and considerations to growth conditions.