Question

In the first step of the monohybrid cross experiment, Mendel selected pea plants which were
(a) Pure tall as male and the pure dwarf as female
(b) Pure tall as female and the pure dwarf as male
(c) Heterozygous tall as male and the pure dwarf as female
(d) Heterozygous tall as female and the pure dwarf as male

Answer 1

Hint: For hybridization, Mendel began with a pair of pea plants with two contrasting traits, i.e., one tall and another dwarf. He called this as a primary hybrid generation (${ F }_{ 1 }$) and offspring were called Filial1 or ${ F }_{ 1 }$ progeny.

Complete Step by Step answer:
Mendel performed cross-breeding experiments on the garden green pea (Pisum sativum). He studied the inheritance of seven different pairs of contrasting characters in this plant but considered only one pair at a time. He crossed two pea plants having contrasting characters (for example tall and dwarf pea plants) by artificial pollination and obtained the hybrids. The resulting hybrid plants were then crossed with one another. He obtained the data from these crosses and analysed the results carefully.
In the first cross, a pure tall female (TT) was crossed with a pure dwarf male (tt).
So, the correct answer is 'Pure tall as female and the pure dwarf as male.'

Additional Information: The seven traits taken by the Mendel for his experiments are:
- Seed shape
- Seed colour
- Flower colour
- Flower position
- Plant height
- Pod shape
- Pod colour
- The dominant and recessive traits were taken of the above characters which are mentioned in the diagram below.

A dominant gene overrides and masks the effect of the recessive gene present on the other copy of the chromosome.

Note: Mendel is known as the father of genetics. He used the pea plant for his cultivation because of the following reasons,
- It can be grown and cultivated very easily. It has many visible distinguishing characteristics like length, the colour of the flower, the colour of seeds. The characters were contrasting.
- The process of self- pollination for getting pure plant was also easily possible as the flowers were bisexual.
- Along with this controlled pollination was also easy to do.
- The life span of the pea plant is also small and it produces a large number of seeds. They had the ideal survival rate and resistance to diseases.
- They are herbaceous and annual plants, and therefore can be grown two to three times in a year.
By the help of pea plant, Mendel came to the conclusion and gave three laws –
- Law of dominance
- Law of segregation
- Law of Independent Assortment.