Biology

Genetics and Plant Breeding

1,177 Questions

Genetics and Plant Breeding explores the principles of heredity, chromosomal inheritance, and hybridization techniques. It includes key concepts like Mendelian genetics, gene linkage, and polygenic inheritance. This topic is essential for students tackling advanced biology or botany sections in competitive examinations.

Mendelian InheritanceChromosome TheoryGene LinkagePolygenic InheritancePlant HybridizationPopulation Genetics Equilibrium

Genetics and Plant Breeding Questions

Multiple choice

Consider the following sentences. (a) A dominant factor or allele expresses itself in the presence or absence of a recessive trait. (b) Darwin proposed that every part of the body produces very small invisible particles called pangenes. (c) A recessive trait is able to express itself only in the absence of a dominant trait. Which of the above statements is/are correct?

  1. Only (a)

  2. Only (b)

  3. Only (c)

  4. All of the above

  5. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

All the statements are correct.

Multiple choice

Consider the following statements. (a) Mendel used peas to explain a monohybrid cross where two traits were crossed. (b) AB blood group is an example of multiple allele inheritance. (c) Mendel proposed law of independent assortment based on the results of the monohybrid cross. Which of the above statements is/are correct?

  1. Only (a)

  2. Only (b)

  3. Only (c)

  4. None of these

  5. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Neither of the above statements is correct.

Multiple choice

Consider the following sentences. (a) Test cross is the cross between progeny in F2 generation with its recessive parent. (b) Test cross is done to know the genotype of parents along with the progeny. (c) All test cross are back cross. Which of the above statements is/are correct?

  1. Only (a)

  2. Only (b)

  3. Only (c)

  4. All of the above

  5. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Statement (c) is correct. All test cross are back cross, which is a form of recurrent hybridization (repeated crossing to a single variety) where a superior characteristic may be added to an otherwise desirable variety..

Multiple choice

Consider the following statements. (a) Mendel's law of Independent Assortment is supported by a 1:1:1:1 test cross ratio. (b) Mendel's law of Segregation is supported by a 1:1:1:1:1 test cross ratio. (c) Assuming complete dominance, a 3:1 phenotypic ratio is expected from mono-hybrid self cross. Which of the above statements is/are incorrect?

  1. Only (a)

  2. Only (b)

  3. Only (c)

  4. All of the above

  5. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Statement (b) is incorrect. Mendel's law of Segregation is supported by a 1:1 test cross ratio.

Multiple choice

Consider the following statements. (a) The heterozygote's phenotype is intermediate between those of the two homozygotes. (b) The heterozygote fully expresses two different and equally expressed alleles. (c) One gene has multiple phenotypic expressions. (d) One gene affects the expression of another gene. Which of the above statements is/are incorrect?

  1. Only (a)

  2. Only (b)

  3. Only (c)

  4. Only (d)

  5. None of the above
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

All the statements are correct.

Multiple choice

Consider the following statements. (a) Tendency of two or more genes of the same chromosomes to remain together during the process of inheritance is known as crossing over. (b) Homo-gametic is the condition in which there are two different types of gametes formed. (c) In the process of crossing over, the crossing over occurs at two points in the same chromosome pair. (d) Allele frequency is a measure of the relative frequency of an allele on a genetic locus in a population. Which of the above statements is/are correct?

  1. Only (a)

  2. Only (b)

  3. Only (c)

  4. Only (d)

  5. None of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Statement (d) is correct. Allele frequency is a measure of the relative frequency of an allele on a genetic locus in a population.

Multiple choice

Consider the following statements. (a) All the genes, which can inherit together from one generation to another generation constitute a linkage group. (b) Genes that are linked but never cross over is known as incomplete linkage. (c) Mutual exchange of blocks of homologous genes between a pair of homologous chromosomes is known as crossing over. (d) The chromosomes in an organism that determine the sex of an individual, are called sex chromosomes. Which of the above statements is/are incorrect?

  1. Only (a)

  2. Only (b)

  3. Only (c)

  4. Only (d)

  5. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Statement (b) is incorrect. Genes that are linked but never cross over is known as complete linkage, not incomplete linkage.

Multiple choice

Consider the following statements. (a) Genetical basis for blood types in human beings is due to the presence of three types of alleles IA, IB, IC. (b) Mendel initially concentrated on the results of two traits at a time. (c) When the inheritance of two traits is considered, they are inherited independently of each other. (d) If parents differing in only one trait were crossed, it is called dihybrid cross. Which of the above statements is/are correct?

  1. Only (a)

  2. Only (b)

  3. Only (c)

  4. Only (d)

  5. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Statement (c) is correct. When the inheritance of two traits is considered, they are inherited independently of each other.

Multiple choice

Dee-geo-woo-gen is a dwarfing gene of

  1. rice

  2. sugarcane

  3. wheat

  4. maize
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Dee-geo-woo-gen is a well-known dwarfing gene from rice (Oryza sativa). It was identified in Taiwanese rice varieties in the 1950s and contributed to the development of semi-dwarf rice varieties during the Green Revolution. The name appears to be a transliteration from Chinese.

Multiple choice

Which of the following statements is/are correct?

a. Genes are thread-like structures in the nucleus of a cell formed of DNA which carry the chromosomes. b. The dominant gene decides the appearance of an organism even in the presence of an alternative gene. c. The recessive gene decides the appearance of a person in the absence of the dominant gene.

  1. a only

  2. b only

  3. c only

  4. b and c

  5. a and c
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This is the correct answer as this statement is correct. The dominant gene decides the appearance of an organism even in the presence of an alternative gene.

Multiple choice

Which of the following statements is/are correct?

a. George Mendel is known as the father of genetics. b. He studied the pattern of inheritance. c. His experiments showed that inherited traits blended in F1 generation.

  1. a and b

  2. a and c

  3. b and c

  4. a only

  5. b only
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This is the correct answer as both the statements are correct. George Mendel is known as the father of genetics and he studied the pattern of inheritance.

Multiple choice

In order to ensure that he had pure breeding plants for his experiments, Mendel

  1. cross-fertilised each variety with each other

  2. did not allow any cross-fertilisation

  3. let each variety self-fertilise for several generations

  4. removed the female parts of the plants

  5. removed the male parts of the plants
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In order to ensure that he had pure breeding plants for his experiments, Mendel let each variety self-fertilise for several generations. Thus, this is the correct answer.