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
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monohybrid cross
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dihybrid cross
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incomplete dominance
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back cross
B
Correct answer
Explanation
The correct answer is option (2).
D
Correct answer
Explanation
The correct answer is option (4).
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All tall
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All dwarf
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50% tall and 50% dwarf
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75% tall and 25% dwarf
C
Correct answer
Explanation
The correct answer is option (3).
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pleiotropy
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multiple alleles
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polygenes
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incomplete dominance
B
Correct answer
Explanation
ABO group of blood in man is an example of multiple alleles.
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polygenes
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complete dominance
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incomplete dominance
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co-dominance
C
Correct answer
Explanation
When a red flowered mirabilis is crossed with white one, the hybrids in F1 and F2 were pink flowered. This is due to incomplete dominance.
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4 phenotypes appear in the ratio 9 : 3 : 3 : 1, if the loci are linked
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4 phenotypes appear in the ratio 9 : 3 : 3 : 1 if the loci are unlinked
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2 phenotypes appear in the ratio 3 : 1 if the loci are unlinked
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3 phenotypes appear in the ratio 1 : 2 : 1 if the loci are unlinked
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.
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spindle elongation
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polyploidy
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spindle formation
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mitosis
B
Correct answer
Explanation
Alkaloid obtained from 'Autumn crocus' is used to induce polyploidy.
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phenotype
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genotype
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alleles
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dominant
B
Correct answer
Explanation
Genetic make up of an organism is called genotype.
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linkage
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inbreeding
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stability
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variation
D
Correct answer
Explanation
Crossing over is advantageous because it brings about recombination or variation.
A
Correct answer
Explanation
AaBb individual can produce 22 gametes, i.e. four gametes.
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4 phenotypes appear in the ratio 9 : 3 : 3 : 1, if the loci are linked
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4 phenotypes appear in the ratio 9 : 3 : 3 : 1, if the loci are unlinked
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2 phenotypes appear in the ratio 3 : 1, if the loci are unlinked
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3 phenotypes appear in the ratio 1 : 2 : 1, if the loci are unlinked
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.
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Height of plants
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Shape of leaves
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Colour of seeds
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Shape of pod
B
Correct answer
Explanation
The seven characters studied by Mendel are: Plant height, Flower position, Pod shape, Pod colour, Flower colour, Seed shape and Seed colour. Shape of leaves is not considered by Mendel.
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1 : 1
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1 : 2 : 1
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9 : 3 : 3 : 1
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7 : 1 : 1 : 7
D
Correct answer
Explanation
In this ratio, the parental type is more than the recombinant type.
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50% red
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100% red
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100% white
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75% red
B
Correct answer
Explanation
Only two types of progenies will be obtained, RR and Rr, and red (R) allele is present in both the situations; it will mask the effect of white.
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crossing-over
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linkage
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synapsis
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terminalization
B
Correct answer
Explanation
The parental types are coupled and do not show independent assortment while the non-parental types show repulsion.