Grain hardness is one of the most important quality characteristics of wheat (Triticum aestivum L.). It is a significant property of wheat grains and relates to milling quality and end product quality. Grain hardness is caused by the presence of puroindoline genes (Pina and Pinb). A collection of 25 genotypes of wheat with unusual grain colour (blue aleurone, purple and white pericarp, yellow endosperm) was studied by polymerase chain reaction (PCR) for the diversity within Pina and Pinb (alleles: Pina-D1a, Pina-D1b, Pinb-D1a, Pinb- -D1b, Pinb-D1c and Pinb-D1d). The endosperm structure was determined by a non-destructive method using light transflectance meter and grain hardness by a texture analyser. Genotype Novosibirskaya 67 and isogenic ANK lines revealed hitherto unknown alleles at the locus for the annealing of primers of Pinb-D1. Allele Pinb-D1c was found to be absent from each genotype. The mealy endosperm ranged from 0 to 100% and grain hardness from 15.10 to 26.87 N per sample.