In a Mendelian cross of red and white varieties of the four O"clock plants, the F1 generation expresses incomplete dominance by having flower which are

In a Mendelian cross of red and white varieties of the four O'clock plants, the F1 generation expresses incomplete dominance by having flowers that are pink. Incomplete dominance occurs when neither of the two alleles (versions of the gene) is completely dominant over the other, resulting in a phenotype (observable trait) that is intermediate between the two. In the case of the four O'clock plants, the gene for flower color has two alleles: one for red and one for white. When a red-flowered plant is crossed with a white-flowered plant, the F1 generation inherits one allele from each parent and expresses an intermediate phenotype of pink flowers. This is because the red pigment and the absence of pigment in the white flowers mix together to create a pink color. The F2 generation resulting from the cross of F1 plants can have a ratio of 1:2:1 for red:pink:white flowers, indicating the incomplete dominance inheritance pattern.