If a heterozygous red flowered plant, (Rr) was self-fertilized, the offspring would be expected to be

If a heterozygous red flowered plant (Rr) was self-fertilized, the offspring would be expected to be a mix of red and white flowered plants in a 3:1 ratio. This is because the R allele is dominant over the r allele, so the heterozygous plant will express the red flowered phenotype. However, during meiosis, the alleles segregate, and each gamete (pollen or egg) only carries one allele. So, half of the gametes will carry the R allele and the other half will carry the r allele. When these gametes combine, the resulting offspring will have different combinations of the R and r alleles, resulting in a 3:1 ratio of red to white flowered plants.