Biology

Genetics and Plant Breeding

1,240 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

Twins that develop from a single zygote are called

  1. heterozygote

  2. identical

  3. non placental

  4. fraternal

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Twins can be either monozygotic ("identical"), meaning that they develop from one zygote, which splits and forms two embryos, or dizygotic ("fraternal"), meaning that they develop from two different eggs. In fraternal twins, each twin is fertilized by its own sperm cell.

Multiple choice

In F2 generation of a dihybrid cross,

  1. 4 phenotypes appear in the ratio 9 : 3 : 3 : 1, if the loci are linked

  2. 4 phenotypes appear in the ratio 9 : 3 : 3 : 1 if the loci are unlinked

  3. 2 phenotypes appear in the ratio 3 : 1 if the loci are unlinked

  4. 3 phenotypes appear in the ratio 1 : 2 : 1 if the loci are unlinked
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

4 phenotypes appear in the ratio 9 : 3 : 3 :1 if the loci are unlinked. It is correct as they have to assort independently.

Multiple choice

In human, the ABO blood groups are determined by a multiple allelic system where IA and IB are co-dominant and dominant to IO. A newborn infant is type A, whose mother is type O. Possible phenotypes of the father are

  1. A, B or AB

  2. A, B or O

  3. O only

  4. A or AB
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Possible genotypes of the father are A or AB, as IA allele is required from one of the parent, as mother does not have IA allele, thus father should have IA allele.

Multiple choice

In the F2 generation of a dihybrid cross,

  1. 4 phenotypes appear in the ratio 9 : 3 : 3 : 1, if the loci are linked

  2. 4 phenotypes appear in the ratio 9 : 3 : 3 : 1, if the loci are unlinked

  3. 2 phenotypes appear in the ratio 3 : 1, if the loci are unlinked

  4. 3 phenotypes appear in the ratio 1 : 2 : 1, if the loci are unlinked
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In the F2 generation of a dihybrid cross, 4 phenotypes appear in the ratio 9 : 3 : 3 :1, if the loci are unlinked.

Multiple choice

Skin colour inheritance in man is

  1. monogenic

  2. polygenic

  3. sex-linked

  4. multiple allelic
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Skin colour inheritance in man is not monogenic, but it is polygenic, controlled by many genes like AABBCC, aabbcc, etc.