In a dihybrid cross, Mendel took a pair of contradicting traits together for crossing; for example color and the shape of seeds at a time. He picked the wrinkled-green seed and round-yellow seed and crossed them. He obtained only round-yellow seeds in the F1 generation. This indicated that round shape and yellow color of seeds are dominant in nature. While the wrinkled shape and green color of seeds are recessive traits. Then, F1 progeny was self-pollinated. This resulted in four different combinations of seeds in F2 generation. They were wrinkled-yellow, round-yellow, wrinkled-green seeds and round-green in the phenotypic ratio of 9:3:3:1.