In pea plants, plant height, seed shape, and seed color are governed by three independently assorting genes. The three genes have dominant and recessive alleles, with tall (T) dominant to short (t), round (R) dominant to wrinkled (r), and yellow (G) dominant to green (g).

What proportion of the round, green seeds (regardless of the height of the plant) in the F2 are expected to breed true? Recall that true-breeding plants are defined as a group of genetically identical homozygous organisms that, when self-fertilized or intercrossed, only produce offspring that have a phenotype identical to the parents.