The shape of summer squash is classified as either long, spherical, or disk-shaped. Disk-shaped fruits are produced when dominant alleles are present at two gene loci, A and B. Spherical-shaped fruits are produced when a dominant allele is present at either the A or B gene loci. Long-shaped fruits are produced when the plant is homozygous recessive for both genes A and B. Two pure breeding plants that produce spherical-shaped fruits are crossed, and all the resultant F₁ progeny plants produce disk-shaped fruits. If the F₁ progeny was self-fertilized, determine the phenotypic ratio of the F₂ progeny.