Q. In Mendelian dihybrid cross when heterozygous round yellow are self crossed, round green offsprings are represented by the genotype :

Q. In Mendelian dihybrid cross when heterozygous round yellow are self crossed, round green offsprings are represented by the genotype :

(a) RrYy, RrYY, RRYy

(b) Rryy, RRyy, rryy

(c) rrYy, rrYY

(d) Rryy, RRyy

Solution :

Correct option : D The genotype of the F1 plants is RrYy. These plants were self-crossed by Mendel. In his dihybrid cross the F2 plants were obtained in the phenotypic ratio 9 (round yellow):3 (round green) :3 (wrinkled yellow):1 (wrinkled green) as shown in the Punnett square. Round seeds can be represented by the genotype RR or Rr as roundness of the seed is a dominant trait and can be homozygous or heterozygous. The green color is homozygous recessive and can be represented as yy. Thus the correct answer is option D.