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

What will be the number of phenotypes in polygenic inheritance in case of human skin color?

  1. 7

  2. 11

  3. 3

  4. 5

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

Number of phenotypes in polygenic inheritance is calculated by = ( 2 x n ) + 1, where n is number of pairs of polygene. As human skin color is controlled by 3 pairs of polygenes, thus number of phenotypes = ( 2 x 3 ) + 1 = 7. Also, phenotypic ratio for human skin color is 1 : 6 : 15 : 20 : 15 : 6 : 1. So, if counted, the answer is 7.

Multiple choice

In capsicum, genotype aabbcc produces 200 gm capsicum and genotype AABBCC produces 260 gm. What will be the contribution of each gene, and what will be the weight of capsicum in progeny, if AAbbcc x aaBBcc?

  1. 20 and 240

  2. 10 and 220

  3. 20 and 280

  4. 10 and 180

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

Contribution of each gene = (maximum wt - minimum wt ) / number of polygene: (260 - 200 ) / 6 = 10, weight of progeny = ( number of dominant gene x contribution of each gene ) + minimum value. Thus, number of dominant gene in progeny = 2 (AaBbcc), weight of progeny = ( 2 x 10) + 200 = 220.

Multiple choice

What are Siamese twins?

  1. Dizygotic twins

  2. Non-identical twins

  3. Monozygotic twins

  4. Identical twins

  5. United twins
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Siamese twins are joined in small area and are called united twins. They can be separated by modern surgical techniques.

Multiple choice

Which of the following statements is/are incorrect? (a) Darwin in 1906, coined the term Genetics. (b) Punnett Square is the chart that shows all the possible combinations of alleles that can result from a genetic cross. (c) The sum of all the genes shared by a population is called as Gene Pool.

  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
A Correct answer
Explanation

Statement (a) is incorrect. William Bateson, not Darwin, in 1906, coined the term Genetics.

Multiple choice

Consider the following statements. (a) Pure breeding plants make up the generation P2. (b) One of the numbers of different forms of a gene is called allele. (c) The probability that F1 plant will be TALL is 70%. (d) The probability that F2 plant will be TALL is 50%. 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
B Correct answer
Explanation

Statement (b) is correct. One of the numbers of different forms of a gene is called allele.

Multiple choice

Consider the following statements. (a) Mendel selected 16 different varieties of the pea and grouped them into eight pairs. (b) The gene responsible for the condition known as sickle-cell anemia demonstrates multiple allele inheritance. (c) When both parents are homozygous for a recessive trait, they run a one-in-four chance that the recessive trait will be expressed in their children. (d) The genotype of the F1 generation is heterozygous. 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. The genotype of the F1 generation is heterozygous.

Multiple choice

Consider the following statements. (a) Thomas Morgan worked on drosophila. (b) Emasculation is the process in which anthers are removed from flowers before maturity. (c) Law of segregation is also called law of splitting of hybrids. (d) Davenport introduced the terms genotype and phenotype. 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
D Correct answer
Explanation

Statement (d) is incorrect. W. L. Johannsen, not Davenport, introduced the terms genotype and phenotype.