Final answer:
A RRyy plant can only produce gametes with the genotype Ry.
Step-by-step explanation:
The gametes a RRyy plant can produce is Ry. This is under the assumption that the plant is diploid and that each gamete must carry one allele for each gene as per Mendel's law of segregation. Since 'RR' is homozygous, the only possible allele for seed shape that the gametes can carry is 'R'. Similarly, 'yy' is homozygous, so the only possible allele for seed color that the gametes can carry is 'y'. Therefore, the only type of gamete this plant can produce is 'Ry'.