Explain the law of independent assortment with reference to seed shape and seed colour in garden tea plant.

Explanation

In a dihybrid cross, Mendel selected two pairs of contrasting characters. He selected the shape and colour of the seed as two characters, for his cross. He recongnished round and wrinkled shape of the seeds as one pair of contrasting characters and yellow and green colour as another pair of contrasting characters.
he crossed a plant having yellow and round seeds with a plant having green and Wrinkled seeds and got `F_(1)` generation. in the `F_(1)`, he got all the plants producing round and yellow seeds. thus he found that yellow and round traits were dominant over green and wrinkled, respectively. Later, he self-crossed the `F_(1) `hybrids and raised `F_(2)` generation. in this generation, he got four types of plants producing Yellow-round, seed yellow-wrinkled seed, green-round seed, and green-wrinkled seed. thus he got two new characters yellow wrinkled seed and green-round seed, in addition to the parental characters.
By using appropriate letters to denote dominant and recessive genes, the dihybrid cross is represented as shown below:


thus in the `F_(2)` generation, he got yellow round, yellow-rinkled, green-round and green wrinkled in the ration of 9:3:3:1, respectively.
Number of pairs of alleles
involved=two pairs
base number=16
phenotypic ratio=9:3:3:1
Genotypic ratio=4:2:2:2:1:1:1:1
Phenotypic classes=Four (Yellow round, yellow wrinkled, green round,g reen wrinkled)
Genotypic lasses=09
Based on the result of dihybrid cross, he came to the conclusion that the four genes for two of contrasting characters are separated independently in the `F_(1) `hybrids because the genes were present on different chromosomes and combined in the `F_(2)` generation to produce four characters.
BAsed on the results of the dihybrid cross, he formulated the second law of heredity namely, the law of independent assortment. it states that "when genes or alleles for two or more separate pairs of contrasting characters are brought together in a hybrid, they separate independent of each other.