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 biology improvement in food resources crop variety improvement improvement if crop varieties improvement in crop variety

Find out the correct sentence.
(i) Hybridization means crossing between genetically dissimilar plants.
(ii) Cross between two varieties is called as inter specific hybridisation.
(iii) Introducing genes of desired character into a plant gives genetically modified crop.
(iv) Cross between plants of two species is called as inter varietal hybridisation.

  1. (i) and (iii)

  2. (ii) and (iv)

  3. (ii) and (iii)

  4. (iii) and (iv)
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Hybridisation is defined as the process of interbreeding between two genetically divergent individuals or two individuals of different species. Therefore, the statement (i) is correct.
Interspecific hybridisation means cross mating between two different species but sharing same genera. For example, a cross breed between a lion and a tiger, they both are from same genus Panthera but different species. So the statement that cross between two varieties is called interspecific hybridisation is wrong.
I am a brinjal farmer, my brinjals are being infected by some beetles every year. I spend a huge sum of money on insecticides and pesticides to protect my crop. Then, a biotechnology company approaches me with a new strain or variety of brinjal plants which have the capability to produce a natural pesticide that makes it resistant to the beetles. My crop is not only saved, but  I also get good yield of brinjals now and earn a lot of money. I do not have to spend extra money on pesticides and insecticides. Basically, I got a brinjal plant with gene of desired character and got a desired genetically modified brinjal plants. Therefore, the statement (iii) is correct.
When the parent plants cross bred are from the same species, but of different variety is called intervarietal hybridisation. For example, a cross bred between two different varieties of wheat plant. They belong to the same species but they are of different variety. Therefore, the statement (iv) is wrong.
Hence, we can conclude that (i) and (iii) are correct statements.

Multiple choice biology improvement in food resources crop variety improvement improvement if crop varieties improvement in crop variety

Select the wrongly matched pair.

  1. Hybrid - Pure breeding progeny.

  2. Incomplete dominance - An exception to Mendelism

  3. Heredity - Transmission of characters from one generation to the next

  4. Allele - Alternate representation of a gene
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Pure breeding varieties are the one that carries same allele for a particular character and pass the trait without change from one generation to next upon selfing (for example, pure breeding tall (TT) plant carries two copies of “T” allele). Hybrids are the one which carries contrasting allele of a particular gene e.g., hybrid tall plant’s genotype is “Tt”. Incomplete dominance refers to the conditions where none of factors of a gene is dominant; the phenotype of heterozygous dominant individual is blend of dominant and recessive traits. Thus, it is an exception to Mendel’s principle of dominance. Heredity is genetic transmission of characters from parent generation to progeny. Alternative forms of a gene are called alleles e.g., alleles for gene for plant height are “T” and “t”. Thus, the correct answer is option A.

Multiple choice biology animals in daily life introduction to reproduction poultry farming food from animals

Breeding in Fowl is done between :

  1. Six month old hen and cock.

  2. One year old hen and two year old cock.

  3. Two year old hen and one year old cock.

  4. Two year old hen and cock.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Answer C) Two year old hen and are year old cock usually a rooter reacts its mortality of 5 moths old. But young rooters are not wood 10 breed because they are case effective. So the rooter of an year old is used for breeding.
A hen also grows and molecular of an age of 6 months But the hen is allowed to grow fully and matured. Hence, two year old hen is used.
Multiple choice biology fruit and seed morphology of the fruit fruit plants: structure and function

Fruit shape in shephered's purse(Capsella bursa) is of two types-triangular and top-shaped. Triangular fruit shape(T) is dominant over top-shape (t). Following table summarises the results of several crosses.

Cross Result
Strain 1 x tt All triangular
Strain 2 x tt 1 triangular : 1 top-shaped
Strain 3 x tt All top-shaped
Strain 4 x tt 3 triangular: 1 top-shaped

Which pair of strains possess the genotype Tt?

  1. Strains 2 and 3

  2. Strains 2 and 4

  3. Strains 1 and 3

  4. Strains 1 and 4
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice zoology mutation dna fingerprinting human genome project and dna fingerprinting instruments in biotechnology

Genetic counsellors can identify heterozygous individuals by

  1. Height of individuals

  2. Colour of individuals

  3. Screening procedures

  4. All of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Genetic counselling is about giving information and advice about the, risks of genetic diseases and their outcomes. Genetic screening is a part of genetic counselling which includes prenatal diagnosis, carrier diagnosis and predictive diagnosis.
Genetic counsellors use screening procedure, where sample of blood, hair follicle etc is processed to extract DNA, the DNA is profiled and specific areas  are identified
So, the correct answer is C 'Screening procedures'


Multiple choice evs modern agriculture agricultural practices in india different types of farming and agriculture various agricultural practices

WhIch of the following is necessary for Improvement of the quality of crops?
1. Introduction
2. Hybridisation
3. Selection
4. Segregation

  1. 1, 2 and 3

  2. 1, 2, 3 and 4

  3. 2, 3 and 4

  4. 2 and 3
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Development of the new variety of plant processing desirable characters from existing ones is known as plant breeding.
Plant introduction means introducing a plant having desirable characters which are a genetic improvement, high yield, disease resistance and vigorous growth from a region of a country where growth naturally to a region or a country where does not occur earlier.
Then the pure line selection is done.
Hybridization is a method of reducing new crop varieties in which two or more plants of unlike genetical constituents are fused together.

So, the correct option is '1, 2 and 3'



Multiple choice botany modes of reproduction why do plants reproduce? reproduction and variation the life cycle of plants

Characters that are transmitted from parents to offspring during reproduction show

  1. Only similarities with parents

  2. Only variations with parents

  3. Both similarities and variations with parents

  4. Neither similarities nor variations
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • Character that are transmitted from parent to offspring during reproduction are similar to parent but they may vary due to mutation, crossing over and genetic recombination.
Multiple choice botany classical genetics incomplete dominance deviation from mendelism inheritance

Phenotypic and genotypic ratio is similar in case of?

  1. Complete dominance

  2. Incomplete dominance

  3. Over dominance

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

In complete dominance, the dominant allele fully masks the recessive allele. Therefore, the phenotype of the heterozygote is identical to the homozygous dominant, making the phenotypic and genotypic ratios identical in a monohybrid cross (3:1 vs 1:2:1 is not the case here, but rather the expression of traits).

Multiple choice botany classical genetics incomplete dominance deviation from mendelism inheritance

The segregration of alleles is a random process and so there is a _______ chance of a gametes containing either allele.

  1. $25\%$
  2. $50\%$
  3. $75\%$
  4. $100\%$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

According to Mendel"s law of segregation, alleles segregate from one another so that the gametes will have only one copy of the particular gene. In a diploid organism, there are two alleles for a particular gene, which segregate and only one of each allele can be present in a gamete, therefore, since there are two alleles for a gene, chances of a gamete containing either of the allele is 50%. 

So, the correct option  is '50%'.

Multiple choice botany classical genetics incomplete dominance deviation from mendelism inheritance

When the phenotypic and genotypic ratios resemble in the F$ _2$ generation, it is an example of

  1. Independent assortment

  2. Qualitative inheritance

  3. Segregation of factors

  4. Incomplete dominance
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Incomplete dominance: It is a type of intragenic (or interallellic) interaction where both the alleles of a given trait express as a blend (mixture) as against a normal Mendelian pattern where one allele is dominant over the other. As a resulting of this blending, an intermediate character is expressed. This situation occurs due to the fact that the dominant gene is not in a position to completely suppress the expression of recessive gene. With the result, the heterozygous offspring will be phenotypically and genotypically different from either of the homozygous parent.

Multiple choice botany classical genetics incomplete dominance deviation from mendelism inheritance

When a hybrid plant with pink (Rr) flower of Mirabilis is crossed with white flower, the expected phenotype ratio is

  1. red : pink : white, 1 : 2 : 1

  2. pink : white, 1 : 1

  3. red : pink, 1 : 1

  4. red : white, 3 : 1
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Hybrid - Rr pink flower and white flower - rr
Genotypes: Rr            x      rr
Gametes:     R, r                 r
Offspring:      Rr, rr
The ratio of pink flower: white flower = 1:1

Multiple choice botany classical genetics incomplete dominance deviation from mendelism inheritance

RR(red) is crossed with rr (white). All Rr offsprings are pink. This indicates that R gene is

  1. Hybrid

  2. Incompletely dominant

  3. Recessive

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

Incomplete dominance refers to a genetic situation in which one allele does not completely dominate another allele and, therefore, results in a new phenotype. It shows that the dominant allele is incompletely dominant.
Examples of incomplete dominance are:

1. A snapdragon flower that is pink as a result of cross-pollination between a red flower and a white flower when neither the white or the red alleles are dominant.
2. A brown fur coat on a rabbit as a result of one rabbit's red allele and one rabbit's white allele not dominating.