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

Heritability for milk production in dairy cattle is:

  1. 50%

  2. 5%

  3. 80%

  4. 30%
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Heritability for milk production is generally considered to be around 0.25 to 0.30 (25-30 percent). This means that about 30 percent of the variation in milk production is due to genetics.

Multiple choice botany pollination and fertilization types of pollination cross pollination pollination and its types

Cross-pollination is preferred over self-pollination because it?

  1. Produces better offspring

  2. Forms new varieties

  3. Induces parthenogenesis

  4. Is economical
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • Cross-pollination can be defined as the transfer of pollen grains from the male reproductive organ (an anther or a male cone) of one plant to the female reproductive organ (a stigma or a female cone) of another plant. 
  • Insects and wind act as the agents of cross-pollination.
  • Cross-pollination helps to produce varieties in species by recombinant genes while self-pollination maintains homozygosity. 
  • So the correct option is 'forms new varieties'. 
Multiple choice botany pollination and fertilization types of pollination cross pollination pollination and its types

Despite high level of heterozygosity, the progeny derived from seed of a cross pollination plant was found to be completely uniform. One reason for this may the phenomenon of 

  1. Parthenocarpy

  2. Apomixis

  3. Induced mutation

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

Because apomixis is a abnormal kind of sexual reproduction in which egg or other cells associated with egg (synergids, antipodals etc) develop into embryo without fertilization and with or without meiosis.

Multiple choice botany pollination and fertilization types of pollination cross pollination pollination and its types

Allogamy is favoured by

  1. Homogamy

  2. Cleistogamy

  3. Monocliny

  4. Dicliny
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Allogamy, also known as cross pollination, is the transfer of pollen grains from the anther of one flower to the stigma of another flower borne on a separate plant.
Dicliny is the presence of only one kind of reproductive whorl in a flower. It is also called unisexuality.
A plant may be monoecious i.e. male and female flowers are present on the same plant. In such cases, both cross pollination and self pollination can occur.
Or the plant may be dioecious i.e. male and female flowers are present on different plants. In such cases, only cross pollination can occur. Thus, dicliny favours allogamy or cross pollination.
So, the correct answer is D.
Multiple choice botany pollination and fertilization types of pollination cross pollination pollination and its types

With reference to mass selection of crop plants, consider the following statements.
a. Mass selection has been more commonly used for the improvement of cross-pollinated crops than the single plant selection.
b. The purpose of mass selection is to increase the frequency of superior genotypes in the population.
c. This method of breeding has been very effective in improving characters governed by many genes.
Which of the statements given are correct?

  1. $1, 2$ and $3$
  2. $1$ and $2$
  3. $1$ and $3$
  4. $2$ and $3$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Mass selection is effective for cross-pollinated crops, aims to increase the frequency of favorable alleles, and is useful for traits controlled by multiple genes (polygenic traits). All three statements are standard principles of plant breeding.

Multiple choice botany pollination and fertilization types of pollination cross pollination pollination and its types

Allogamy is best favoured by ...............

  1. Cleistogamy

  2. Dicliny

  3. Homogamy

  4. None above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In plants, allogamy is used specifically to mean the use of pollen from one plant to fertilize the flower of another plant and are usually synonymous with the term cross fertilization , though the latter can be used more specifically to mean pollen exchange between different plant strains or even different individuals. Allogamy is best favoured by Dicliny. Dicliny refers to unisexual flowers. This is of two types: monoecy and dioecy.

Multiple choice botany pollination and fertilization types of pollination cross pollination pollination and its types

Outbreeding devices which is/are strcturally bisexual but functionally unisexual

  1. Dichogamy

  2. Herkogamy

  3. Dicliny

  4. Both A and B
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Continous self-pollination or inbreeding leads to inbreeding depression, a condition where the decrease in genetic vigor and vitality results in reduced fitness in offsprings.
Dichogamy is the condition in some flowering plants where the pistils and stamens mature at different times, thus preventing self-pollination.
It is of two types: protandry and protogyny.

So, the correct answer is 'Dichogamy'.

Multiple choice

What is the term for the genetic makeup of an individual?

  1. Genome

  2. Genotype

  3. Phenotype

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

Genotype refers to the genetic makeup of an individual, including all of the alleles they carry for a particular gene or set of genes.

Multiple choice

What is the term for the observable characteristics of an individual?

  1. Genome

  2. Genotype

  3. Phenotype

  4. Karyotype
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Phenotype refers to the observable characteristics of an individual, such as their physical appearance, behavior, and physiological traits.

Multiple choice

Which of the following is NOT a type of genetic inheritance?

  1. Autosomal dominant

  2. Autosomal recessive

  3. X-linked dominant

  4. Mitochondrial inheritance
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Mitochondrial inheritance is not a type of genetic inheritance in the same way as autosomal and X-linked inheritance, as it involves the transmission of genetic material from the mother to her offspring through the mitochondria.

Multiple choice

What is the difference between a dominant allele and a recessive allele?

  1. A dominant allele is an allele that is expressed in the phenotype of an organism, while a recessive allele is an allele that is not expressed in the phenotype of an organism

  2. A dominant allele is an allele that is expressed in the genotype of an organism, while a recessive allele is an allele that is not expressed in the genotype of an organism

  3. A dominant allele is an allele that is expressed in the phenotype of an organism, while a recessive allele is an allele that is expressed in the genotype of an organism

  4. A dominant allele is an allele that is expressed in the genotype of an organism, while a recessive allele is an allele that is not expressed in the genotype of an organism
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A dominant allele is an allele that is expressed in the phenotype of an organism. This means that the allele is visible in the organism's physical appearance or behavior. A recessive allele is an allele that is not expressed in the phenotype of an organism. This means that the allele is not visible in the organism's physical appearance or behavior.

Multiple choice

What is a heterozygote?

  1. An organism that has two different alleles for a gene

  2. An organism that has two copies of the same allele for a gene

  3. An organism that has one copy of a dominant allele and one copy of a recessive allele for a gene

  4. An organism that has two copies of a dominant allele and one copy of a recessive allele for a gene
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A heterozygote is an organism that has two different alleles for a gene. This means that the organism has one copy of the dominant allele and one copy of the recessive allele for the gene. Heterozygotes can express both the dominant and recessive traits for the gene.

Multiple choice

What is a homozygote?

  1. An organism that has two different alleles for a gene

  2. An organism that has two copies of the same allele for a gene

  3. An organism that has one copy of a dominant allele and one copy of a recessive allele for a gene

  4. An organism that has two copies of a dominant allele and one copy of a recessive allele for a gene
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A homozygote is an organism that has two copies of the same allele for a gene. This means that the organism has two copies of the dominant allele or two copies of the recessive allele for the gene. Homozygotes can only express one trait for the gene.

Multiple choice

What are the requirements for obtaining plant variety protection?

  1. The plant variety must be new, distinct, uniform, and stable

  2. The plant variety must have a name

  3. The plant variety must be registered with the appropriate authority

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

In order to obtain plant variety protection, the plant variety must be new, distinct, uniform, and stable. It must also have a name and be registered with the appropriate authority.