Quiz on heterosis: Plant genetics multiple choice objective questions

Read MCQ on heterosis. This quiz includes multiple choice objective questions from genetics and plant breeding. Topics: Introduction to heterosis, dominance hypothesis, overdominance hypothesis, plant breeding, interspecific cross,

MCQ on heterosis

Question 01. Who used the term heterosis for the first time?

(a). Shull.
(b). Keith Downey.
(c). Thomas Andrew Knight.
(d). Niels Ebbesen Hansen.

Question 02. Which is true about heterosis?

(a). Superiority of an F1 hybrid over its male parent.
(b). Superiority of an F1 hybrid over its female parent
(c). Superiority of an F1 hybrid over both of its parents.
(d). None of the above mentioned.

Question 03. By what name is it also known as?

(a). Hybrid vigor.
(b). Outbreeding enhancement.
(c). Both a and b.
(d). None of the above.

Question 04. Who developed the dominance hypothesis?

(a). James Crow.
(b). Charles Davenport.
(c). Koelreuteris.
(d). None of the above.

Question 05. What is dominance hypothesis?

01: It is the suppression of undesirable recessive alleles from one parent by dominant alleles from the other.
02: It is the suppression of desirable recessive alleles from one parent by dominant alleles from the other.
03: It is the suppression of undesirable dominant alleles from one parent by recessive alleles from the other.
04: It is the suppression of desirable dominant alleles from one parent by dominant alleles from the other.

(a). Only 1 is true.
(b). Either 1 or 2 is true.
(c). Only 3 is true.
(d). Either 3 or 4 is true.

Question 06. Which one of the following is the genetic basis of heterosis?

(a). Hybridization.
(b). Dominance theory.
(c). Mutation.
(d). None of the above.

Question 07. Developed the overdominance hypothesis?

(a). Edward M. East.
(b). George Shull.
(c). Both a and b.
(d). James Crow.

Question 08. How is heterosis different from inbreeding?

Inbreeding results from matings between closely related individuals.

Heterosis results from crossing between unrelated strains.

2. It is decline in fitness and vigour with decreased heterozygous.

In heterosis the unfavourable recessive genes of one line (parent) are covered by favourable dominant genes of other parent.

3. It results due to fixation of unfavourable recessive genes in F2.

In this case unfavourable recessive genes of one lien (parent) are covered by favourable dominant genes of other parent.

(a).
(b).
(c).
(d).

Question 09. There are three parents, parent A, Mid parent, and parent B.The mean value of parent A is 10, and the mean value of F1 is also 10. What will be the phenomenon?

(a). Complete dominance.
(b). Partial dominance.
(c). No dominance.
(d). Heterosis.

Question 10. There are three parents, parent A, Mid parent, and parent B.The mean value of parent B is <8 but >6, and the mean value of F1 is <6 What will be the phenomenon?

(a). No dominance.
(b). Heterosis.
(c). No dominance.
(d). Complete dominance.

Question 11. Which is true statement?

(a). Interspecific crosses show lesser heterosis than intraspecific crosses.
(b). Interspecific crosses show greater heterosis than intraspecific crosses.
(c). Interspecific crosses show same degree of heterosis than intraspecific crosses.
(d). None of the above.

Question 12. According to Karpechenko (1927), what type of heterosis will be exhibited due to cross between Raphanus sativus and Brassica oleracea?

(a). Biomass.
(b). Colour.
(c). Shape and size.
(d). None of the above.

Question 13. Which is also known as single gene heterosisor super dominance theory?

(a). Dominance hypothesis.
(b). Overdominance hypothesis.
(c). Both a and b.
(d). None of the above.

Question 14. What is dominance of linked gene hypothesis?

(a). Where quantitative characters are governed by few genes.
(b). Where qualitative characters are governed by many genes.
(c). Where quantitative characters are governed by many genes.
(d). Where qualitative characters are governed by few genes.

Question 15. Which is a similarity between dominance and overdominance?

(a). Reduced vigour and fertility due to inbreeding.
(b). Heterosis due to inbreeding.
(c). Both a and b.
(d). Genetic diversity in parents due to inbreeding.

Question 16: Considering ‘inbreds as vigorous as the F1 hybrids’, which is a difference between dominance and overdominance?

(a). Dominance: Can be isolated.
(b). Overdominance: Can’t be isolated.
(c). Both a and b.
(d). None of the above.

Question 17: How would you fix heterosis?

(a). Vegetative propagation.
(b). Apomixis.
(c). Balanced lethal system.
(d). All of the above.

Question 18: Which one of the following factor does not affect heterosis?

(a). Genetic base of parents.
(b). Mode of pollination.
(c). Genetic diversity of parents.
(d). Adaptability of F1.

Answer key

1.	a	6.	b
2.	c	7.	c
3.	c	8.
4.	b	9.	a
5.	a	10.	b

11.	b	16.	c
12.	a	17.	d
13.	b	18.	d
14.	c	19.
15.	c	20.

Explanations

01: The term heterosis was used by Shull in 1914 for the first time.

02: Heterosis is defined as the superiority of an F1 hybrid over both of its parents in terms of yield and some other characters.

03: It is also known as hybrid vigor and outbreeding enhancement.

04: Charles Davenport developed the dominance hypothesis in 1908.

05: This hypothesis attributes to the suppression of undesirable recessive alleles from one parent by dominant alleles from the other.

06: Dominance theory is the genetic basis of heterosis.

07: Edward M. East in 1908, and George Shull in 1908, have developed the overdominance hypothesis independently.