Answer:
1 : 1
Step-by-step explanation:
According to the question, the parents are heterozygous (RrYy) and each would produce four types of gametes: RY, Ry, rY, ry.
Random mating between gametes of two parents gives phenotype ratio 9 round yellow: 3 round green : 3 wrinkled yellow : 1 wrinkled green.
Hence, ratio of round seeds ( 9 + 3 ) to yellow seeds color (9 + 3) is 12:12 = 1:1.