A homozygous plant having round (R) and yellow (Y) seed is crossed with the homozygous plant having wrinkled (r) and green (y) seeds. Answer the following questions based on observation.
i) Give the scientific name of the plant on which Mendel conducted his hybridization experiments.
ii) Give the genotype of the $F_{1}$ generation.
iii) Give the dihybrid phenotypic ratio and the phenotype of the offspring of the $F_{2}$ generation when two plants of $F_{1}$ generation are crossed.
iv) Name and state the law which explains the dihybrid ratio.
v) Give the possible combinations of gametes that can be obtained from $F_{1}$ hybrid.

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Solution

i) Pisum sativum is the scientific name of a pea plant.
ii) The genotype of the F $_{1}$ generation is RrYy.
iii) The phenotypic ratio of F $_{2}$ generation is 9:3:3:1 where phenotypes of offsprings are - Round and Yellow, Round and green, Wrinkled and yellow and Wrinkled and green.
iv) According to Mendel's law of independent assortment, during the inheritance of two or more characters, the assortment of individual traits takes place independently during gamete formation. Thus each allele of a pair segregates independently and each gamete formed contains one allele of that trait.
v) F $_{1}$ genotype is RrYy. So, the possible gamete combinations are
1. RY= Round yellow
2. rY = Wrinkled yellow
3. Ry= Round green
4. ry = Wrinkled green

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