To determine the frequencies of the genotypes, you first find their probabilities from the Punnett square (e.g., 2/16 for Ppqq). Multiplying by 1000, the total number of seeds, converts these probabilities into actual counts. For example, (2/16) * 1000 = 125 seeds with the Ppqq genotype. This approach ensures you have the correct number of seeds for each genotype, reflecting their expected proportions in a large sample.