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 zoology molecular basis of inheritance genome projects human genome project human genome project and dna fingerprinting

The semi dwarf wheat varities are develop from the introduction of dwarf gene.

  1. Lerma
  2. $Norin-10$
  3. $Norin-q$
  4. Both $(2)$ and $(3)$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Semi-dwarf wheat varieties that revolutionized agriculture during the green revolution were developed using the dwarfing genes introduced from the Japanese variety Norin-10.

Multiple choice bio-chemistry immunity and blood groups active and passive immunity acquired immunity innate and acquired immunity

Find the correct statement with respect to HLA system. 

  1. Each individual inherit one pair of haplotype from each parent.

  2. Siblings will have identical haplotype.

  3. MHC - 1 protein present on all cells including erythrocytes.

  4. Macrophages, B-cells, dendritic cells have MHC - II protein on its surface.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

a) HLA system is also called as human leukocyte antigen system. It is a gene complex which encodes for the major histocompatibility complex (MHC) in humans. HLA haplotype is the set of histocompatibility genes that are on the same chromosome and are inherited together. Each individual inherits one pair of HLA haplotypes from each parent. 

b) Each parent has 2 HLA haplotypes on the chromosomes. Hence, there are 1 in 4 chance siblings will have identical haplotype. 
c) MHC I protein is present on all nucleated cells. Since erythrocytes are enucleated, they do not have MHC I proteins on them. 
MHC II protein is present on surface of marcophages, monocytes and dendritic cells. These are responsible for antigen presentation to T cells.
Thus, the correct answer is 'Each individual inherit one pair of the haplotype from each parent.'

Multiple choice zoology the paths traversed by life mutational theory of evolution theories of evolution other theories of evolution

Mutations were first reported by De Vries in

  1. Pea

  2. Datura

  3. Oenothera lamarckiana

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

De Vries discovered new forms among a display of the evening primrose (Oenothera lamarckiana) growing wild in an abandoned potato field. Taking seeds from these, he found that they produced many new varieties in his experimental gardens; he introduced the term mutations for these suddenly appearing variations.

So, the correct answer is 'Oenothera lamarckiana'.

Multiple choice zoology immune system active and passive immunity immunity related disorders and problems diseases and immunity

Number of haplotypes present in an individual is 

  1. One

  2. Two

  3. Six

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

A haplotype (haploid genotype) is a group of alleles in an organism that are inherited together from a single parent. It is used in the collection of specific alleles (that is, specific DNA sequences) in a cluster of tightly linked genes on a chromosome that are likely to be inherited together. An individual will have two haplotypes, although at a population level there may be numerous haplotypes for any given stretch of chromosomal DNA.

So, the correct answer is 'Two'.

Multiple choice zoology immune system active and passive immunity immunity related disorders and problems diseases and immunity

Haplotypes are identical in

  1. Identical twins

  2. Brothers and sisters

  3. Children and parents

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

A haplotype (haploid genotype) is a group of alleles in an organism that are inherited together from a single parent. It is used in the collection of specific alleles (that is, specific DNA sequences) in a cluster of tightly linked genes on a chromosome that are likely to be inherited together. The dizygotic twin pairs share two HLA haplotypes more often than ordinary siblings and thus might be genetically more alike.

So, the correct answer is 'Identical twins'.

Multiple choice zoology immune system active and passive immunity immunity related disorders and problems diseases and immunity

Haplotype is

  1. A single genome

  2. Major histocompatability compklex

  3. Chain of HLA alleles inherited together

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

A haplotype (haploid genotype) is a group of alleles in an organism that are inherited together from a single parent. It is used in the collection of specific alleles (that is, specific DNA sequences) in a cluster of tightly linked genes on a chromosome that are likely to be inherited together.

So, the correct answer is 'Chain of HLA alleles inherited together'.

Multiple choice zoology why do we fall ill health introduction to health health and its maintenance

John, a male hemophiliac, marries Jane, a normal woman, and together they have four children, two boys (Mark and Mike) and two girls (Molly and Mary). None of the children display the symptoms of hemophilia. Mark, Mike, Molly, and Mary all marry normal individuals and have children. None of Mark's or Mike's children, male or female, display symptoms of hemophilia, but the sons of Molly and Mary all display symptoms of hemophilia while the daughters of Molly and Mary do not. Which of the following individuals are heterozygous for hemophilia?

  1. John, Mark, and Mike

  2. Mark, Mike, Molly, and Mary

  3. John and Jane

  4. Molly and Mary

  5. Mark and Mike
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Hemophilia is sex linked recessive disorder. Gene responsible for it present on X chromosome and only expresses in dominant state. Out of four children of john (hemophiliac male) and Jane (normal woman), both the girls Molly and Mary become heterozygous for hemophilia as they got hemophiliac X chromosome from father only, which they pass on to their children resulting sons with hemophilia expressed and daughters are either normal heterozygous for hemophilia. The boys Mark and Mike are normal as they don't get hemophiliac X chromosome from father and when they married with normal individuals, all their children would be normal. Thus, the correct answer is ' Molly and Mary.'

Multiple choice zoology why do we fall ill health introduction to health health and its maintenance

John, a male hemophiliac, marries Jane, a normal woman, and together they have four children, two boys (Mark and Mike) and two girls (Molly and Mary). None of the children display the symptoms of hemophilia. Mark, Mike, Molly, and Mary all marry normal individuals and have children. None of Mark's or Mike's children, male or female, display symptoms of hemophilia, but the sons of Molly and Mary all display symptoms of hemophilia while the daughters of Molly and Mary do not. If one of Mike's daughters marries a normal man, what is the probability that one of their children will display symptoms of hemophilia?

  1. 0%

  2. 25%

  3. 50%

  4. 75%

  5. 100%
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Haemophilia is a sex-linked recessive disorder. Gene responsible for it present on X chromosome and only expresses in a dominant state. Out of four children of John (haemophiliac male) and Jane (normal woman), both the girls Molly and Mary become a carrier for haemophilia as they got haemophiliac X chromosome from John, which they pass on to their children resulting sons with haemophilia expressed and daughters are either normal or carrier. The boys Mark and Mike are normal as they don't get haemophiliac X chromosome from father and when they married with normal individuals, all children would be normal. Thus, the correct answer is '0%.'
Multiple choice botany plant breeding method of plant breeding for crop improvement plant breeding for food production biotechnology

Wide hybridisation has been used for producing

  1. Haploids

  2. Dihaploids from tetraploids

  3. Trihaploids from hexaploids

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

Wide hybridization can be used to transfer the desirable variability. It is used for producing haploids, diploids from tetraploids and trihaploids from hexaploids.

So, the correct answer is 'All the above.'

Multiple choice botany plant breeding method of plant breeding for crop improvement plant breeding for food production biotechnology

First artificial hybrid was obtained by crossing sweet william and carnation in $1717$ by 

  1. G.J Mendel

  2. M.S Swaminathan

  3. P.Maheshwari

  4. Thomas Fairchild
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A. G.J Mendal is known for his discovery of fundamental laws of inheritance.

B. M.S Swaminathan is responsible for introducing and further developing high-yielding varieties of wheat in India.
C. P. Maheshwari was the first person to to grow a plant after natural fertilization in a test tube containing artificial culture medium.
D. Thomas Fairchild was responsible for first artificial hybrid.
So, the correct answer is 'Thomas Fairchild'.

Multiple choice botany plant breeding method of plant breeding for crop improvement plant breeding for food production biotechnology

Norin-10 gene is

  1. Dwarf gene of rice

  2. Dwarf gene of wheat

  3. Dwarf gene of tomato

  4. Smut resistant gene of wheat
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The Rht-B1b and Rht-D1b dwarfing genes were derived from Norin-10, which was a semi-dwarf variety bred in Japan and released in 1935 (Gale and Youssefian, 1985). Norin-10 was used in US breeding programs in the 1950s in order to improve lodging resistance in winter wheat, in which lodging was a serious problem when high rates of nitrogen fertilizers were applied. A selection from a cross of Norin-10 with the US variety, Brevor was particularly promising and was used by Borlaug in the development of the green revolution wheat varieties. Wheat Norin-10 is a semi-dwarf wheat cultivar with very large ears that was bred at an experimental station in Iwate Prefecture, Japan. Norin-10 helped developing countries, such as India and Pakistan, to increase the productivity of their crops from approximately 60% during the green revolution. Thus, the correct answer is option B.

Multiple choice botany plant breeding method of plant breeding for crop improvement plant breeding for food production biotechnology

Crosses between the plants of the same variety are called as

  1. Interspecific

  2. Intervarietal

  3. Intravarietal

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

In intravarietal hybridization, the crosses are made between the plants of same variety. Thus, option C is correct.

Intervarietal hybridization is in which parents involved in hybridization belong to the same species. In crop improvement programme this type of hybridization is commonly used. E.g., crossing of two varieties of wheat or other crops. 
Interspecific hybrids are bred by mating two species, normally from within the same genus.
Hybrids between different genera (such as between sheep and goats) are known as intergeneric hybrids.

Multiple choice botany plant breeding method of plant breeding for crop improvement plant breeding for food production biotechnology

Hexaploid or moderm wheat developed through ______________.

  1. Hybridomas

  2. Chromosome doubling

  3. Hybridisation

  4. Hybridisation and chromosome doubling
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Modern hexaploid wheat (Triticum aestivum) arose through the combination of hybridization between different wild grass species followed by spontaneous chromosome doubling (polyploidy) to restore fertility.

Multiple choice botany plant breeding method of plant breeding for crop improvement plant breeding for food production biotechnology

Majority of improved Indian Rice varieties have arisen from a cross between

  1. Oryza sativa indica $\times$ Oryza nivara
  2. Oryza sativa indica $\times$ O. sativa japonica
  3. O. sativa japonica $\times$ O. nivara
  4. O. rufipogon $\times$ O. nivara.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Improved Indian rice varieties, such as those developed during the Green Revolution, were primarily derived from crosses between the indica subspecies (native to India) and the japonica subspecies (known for high yield).

Multiple choice botany plant breeding method of plant breeding for crop improvement plant breeding for food production biotechnology

Four inbred/pure lines of Maize are crossed. The cross is

  1. Double cross

  2. Dihybrid cross

  3. Tetrahybrid cross

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

A cross involving four inbred or pure lines of maize is known as a double cross, which is commonly produced by crossing two different single-cross hybrids to restore vigor and uniformity in commercial maize production.