Explain the inheritance of one gene with reference to stem height of Garden Pea plant.

Explanation

Monohybrid cross: Mendel selected two polants. One with tall and the other with dwarf to get `F_(1)` generation. To his surprise, he got all tall plants in the `F_(1)` generation.
Parents: Tall plant`xx`Dwarf plant
`F_(1):to` All tall plants
Thus, the tall character appeared in the `F_(1)` generation but dwarf character did not appear. He self crossed the `F_(1)` plants and raised the `F_(2)` generation. Suprisingly, he got both tall and dwarf plants in the ratio of 3:1 respectively. this ratio is called phenotypic ratio. he repeated the experiment by taking other contrasting characters and got the same result.
`F_(1) to` Tall plant`xxF_(1)` Tall plant
`F_(2) to ` Tall plants: Dwarf plants.
3:1
Based on these results, he concluded that the tall character is dominant and the dwaf character is recessive. then he used appropriate symbols to designate the dominant for dominant factors and small letters of the same type of denote the recessive alleles. the monohybrid cross ca be represented as below.
.
Number of plants of alleles involved -1 pair
Base Number=4
Phenotypic ratio=3:1 (3 tall: 1 dwarf)
Genotypic ratio: 1:2:1
Phenotypic classes-Two (tall and dwarf only)
Genotypic classes -3
(1 homozygous tall, 2 heterozygous tall and 3 homozygous dwarf).