40. Which one of the following is the most appropriate definition of ‘Gene Pyramiding’ in plants?
(1) Introducing different genes for resistance to a specific pest in different genotypes.
(2) Introducing a single gene for resistance to a particular pest in different genotypes.
(3) Introducing different genes for resistance to a single pest in a single genotype.
(4) Introducing a single gene for resistance to multiple pests in different genotypes.
The correct answer is (3) Introducing different genes for resistance to a single pest in a single genotype.
Gene pyramiding in plants means stacking multiple resistance genes for the same pest or pathogen into one genotype so that the plant carries several distinct resistance genes simultaneously. This makes resistance more durable because the pest must overcome several genes at once, which is much less likely than breaking a single gene.
Explanation of each option
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Introducing different genes for resistance to a specific pest in different genotypes – Incorrect
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Here, each genotype carries only one resistance gene.
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That is simple gene deployment across varieties, not pyramiding within a single plant.
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Introducing a single gene for resistance to a particular pest in different genotypes – Incorrect
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This is the spread of one R‑gene into many cultivars (gene dissemination).
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There is no stacking of multiple genes in the same genotype.
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Introducing different genes for resistance to a single pest in a single genotype – Correct
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Multiple resistance genes (often against different races/biotypes of the same pest or pathogen) are combined into one plant line.
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This is the textbook definition of gene pyramiding and is commonly done using marker‑assisted selection or gene stacking.
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Introducing a single gene for resistance to multiple pests in different genotypes – Incorrect
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One gene cannot typically provide resistance to many unrelated pests.
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Even conceptually, this again describes spreading one gene across genotypes, not pyramiding multiple genes into one.
