Question
Question: Mendel for his studies chose pea plants and considered many contrasting characteristics present in t...
Mendel for his studies chose pea plants and considered many contrasting characteristics present in the pea plants. One of the characteristics not considered by him was
A: Plant height
B: Plant colour
C: Pod shape
D: Pod colour
Solution
Mendel for his studies chose the garden pea plant scientific name of pea is Pisum sativum (2n=14). He did his experiment for 7 years and chose 7 contrasting characters which are mainly related to pod, seed, height, and position.
Complete answer: Mendel selected Pisum sativum the edible pea for his experiment which has a pure breeding variety. He took two years to check that his experimental materials are pure breeding. Pisum sativum is ideal for controlled breeding, normally it undergoes self-breeding and is cross-bred manually. Pure varieties of peas were easily available. Pea plants show a number of contrasting characters. There were seven pairs of contrasting traits in Pisum sativum which were studied by Mendel. Pea plant is an annual plant whose lifespan is very short and gives results within 3 months. A large number of seeds are produced per plant.
The following table represents the 7 contrasting characters selected by Mendel:
| Character | Dominant Trait | Recessive Trait |
|---|---|---|
| Seed shape | Round(R) | Wrinkled(r) |
| Seed colour | Yellow(Y) | Green(y) |
| Flower colour | Violet(V) | White(v) |
| Pod colour | Green(G) | Yellow(g) |
| Flower position | Axial(A) | Terminal(a) |
| Pod shape | Inflated(I) | Constricted(i) |
| Stem height | Tall(T) | Dwarf(t) |
The term character is basically used for a feature of an individual such as flower colour that varies among individuals. Traits that appear always in two opposing conditions, is dominant and the other one is recessive are called contrasting characters. Monohybrid crosses, dihybrid crosses, trihybrid crosses were performed by Mendel separately involving traits of one character, two characters, three characters.
Hence, the correct option is (B).
Note: 2 shapes (seed shape, pod shape), 3 colour (seed colour, flower colour, pod colour), flower position and stem height were the 7 contrasting traits selected by Mendel. Initially, Mendel selected 32 varieties for his experiment after self breeding to obtain pure varieties, the number was reduced to 22 and finally, Mendel selected 7 pairs.