In genetics, a backcross (BC) is a cross between a hybrid and one of its parents or an individual genetically similar to its parent. If two heterozygous (Rr) plants (where R represents the dominant red allele and r represents the recessive white allele) are crossed, the expected phenotypic ratio would be 75% red and 25% white. This is because three out of the four possible combinations (RR, Rr, rR) would result in red flowers, while only one combination (rr) would result in white flowers.