Chhattisgarh Board Solutions for Chapter: Heredity: from Parents to Offsprings, Exercise 5: Assessment

Some people can roll their tongue (roller represented by RR/Rr) and this is an autosomal dominant character. Those who cannot roll have the recessive factors (Non-roller represented by rr).

A child is capable of rolling her tongue. Her brother fails to roll the tongue while two of her sisters can roll their tongues. If both of the parents can roll their tongue, what do you think would be the combinations of factor in them?

When a blue flowered plant (Bb) is crossed with a white flowered plant (bb) what are the combinations possible in offspring generation?

A variety of cow named “Zeba” is adapted to survive in hot conditions. Another variety “sahiwal” gives 20,000 litres of milk every year. The variety “Angush” has a well built body. If we want to acquire maximum milk from a variety of cow here in Chhattisgarh, which verities of cows do you think must be crossed? Give reasons for your answer.   

How will our knowledge of heredity help in improving our crop plants to acquire maximum production?

How can we choose suitable characters to obtain new varieties of plants?

A farmer sowed seeds of purple flowered pea plants and claimed that all plants in the following generation would have purple flowers. Was he right? Why/why not?

We have been able to successfully obtain pink-flowered rose plants by crossing white and red coloured rose plants respectively. Do you think that some characters do intermix? Why? Site some other examples of this type, that are related to agriculture.

Can we develop high yielding variety seeds by hybridisation? Can such seeds be developed only by crossing pure varieties?