In genetics, alleles may prove dominance over each other, where alleles have the capability to exclude each other from showing in the phenotype. In such an occasion the allele that shows in phenotype is called dominant. By crossbreeding plants of different colors and noting what color the offspring present, it is possible to make statements on which of those two colors is dominant based on the frequency by which each parental color is expressed in the offspring. This study explores the dominance of colors expressed in flowering plants Streptocarpus sp., by crossbreeding different colors in the parental generation. Crossbreeding has been performed occasionally in spring for approximately three years. A total of 124 crosspollinations were performed, which yielded 41 flowering offspring. All offspring came from crosses where the parental plant had flowers of either purple or pink color and all offspring presented flowers of either one color. In this study, at least two alleles were determined to exist: one for the purple color and one for the pink color. The allele for purple color was determined as dominant over the allele for pink color. Due to intermediate colors of parental colors appearing in offspring it is also theorized that flower color may be determined by more than one diploid locus. The base color of the flower seems to be determined by a gene different from the pattern of the flower.
Key words: crosspollination, inheritance, dominance, allele, phenotype.