Question

Name the plant Mendel used for his experiment. What type progeny was obtained by Mendel in ${F_1}$ and ${F_2}$ generations when he crossed with tall short plants? Write the ratio he obtained in ${F_2}$ generation plants.

Answer 1

Mendel conducted his experiments on Pisum sativum or pea plant. He took a pure tall plant and crossed it with a dwarf plant. The progeny thus obtained was called ${F_1}$ progeny (First filial progeny) and it was all tall. Then he self pollinated the ${F_1}$ generation progeny to obtain ${F_2}$ generation. In ${F_2}$ generation (second filial generation), he found that $75\%$ plants were tall and $25\%$ were dwarf.

Complete answer:
Mendel used a garden pea plant (Pisum sativum) for his experiments. A cross between two parents that differ in only one heritable character is called monohybrid cross and the resulting hybrid is called monohybrid. When he crossed pure tall and pure short plants, it is also considered a monohybrid cross. In ${F_1}$ generation, all stamens from the flowers of the tall stem plants were removed so that they acted as female plants. On the other hand all the pistols from the flowers of the dwarf stem plants were removed so that they acted as male plants. These plants are called parents and denoted as symbol P. He collected seeds obtained from cross pollination of parent plants and sewed them. All plants obtained from these seeds had tall stems. He marked these plants as ${F_1}$ generation plants. ​
Mendel allowed the plants of ${F_1}$ generation to reproduce by self pollination and their seeds were obtained. When he showed these seeds, they grew into tall stem plants and dwarf stem plants of ${F_2}$ generation, giving nearly a $3:1$ ratio of tall stem and dwarf stem plants. The most significant feature ${F_2}$ generation was that dwarfness disappeared in ${F_1}$ generation but reappeared in about $25\%$ plants of the ${F_2}$ generation.

Note: Mendel used a pea plant for his experiment. When Mendel performed a cross between a tall plant and dwarf plant he found that all the plants in ${F_1}$ generation are tall. In ${F_2}$ generation $75\%$ of plants were tall while $25\%$ of plants were dwarf so the ratio was $3:1$. The ratio obtained in ${F_2}$ generation is $3:1$.