Which one of the following is the most appropriate definition of 'Gene Pyramiding' in plants?
Introducing different genes for resistance to a single pest in a single genotype.
Gene Pyramiding Explained in Plants
Gene pyramiding in plants is a strategy used in breeding to improve resistance to pests or diseases. It involves combining multiple resistance genes that are effective against the same target pest or disease into a single plant variety or genotype.
The main goal of gene pyramiding is to create more durable and stable resistance. A single resistance gene can sometimes be overcome by the pest or pathogen evolving. By stacking multiple genes, it becomes much harder for the pest or pathogen to adapt and overcome the combined resistance.
Analyzing Gene Pyramiding Options
Let's look at the provided options and see how they fit the definition of gene pyramiding:
- Option 1: Introducing different genes for resistance to a specific pest in different genotypes. This describes introducing resistance genes into different plant lines, not necessarily combining them into one. This is not gene pyramiding.
- Option 2: Introducing a single gene for resistance to a particular pest in different genotypes. This is simply introducing a single gene into different plant lines. This does not involve stacking multiple genes and is not gene pyramiding.
- Option 3: Introducing different genes for resistance to a single pest in a single genotype. This precisely matches the definition of gene pyramiding. Multiple (different) genes are introduced to combat one specific target (a single pest), and they are combined within one plant line (a single genotype).
- Option 4: Introducing a single gene for resistance to multiple pests in different genotypes. This describes a single gene that might provide broad-spectrum resistance or is introduced into various lines. It does not involve stacking multiple genes against a single target and is not gene pyramiding.
Understanding the Correct Gene Pyramiding Definition
Based on the analysis, the definition that best describes gene pyramiding is introducing different genes for resistance to a single pest in a single genotype. This approach is crucial in modern plant breeding for developing robust and long-lasting resistance to specific threats, thereby reducing the reliance on pesticides and improving crop yields.
Important Questions from Inheritance Biology
Which one of the following conditions associated with chromosome 15 may cause Prader-Willi syndrome?
Recessive lethal alleles are never completely eliminated from the population because:
Red-blue colour blindness is a human X-linked recessive disorder. The two parents with normal colour vision have two sons. Son 1 has 47, XXY chromosome composition and is colour blind. Son 2 has 46, XY and is also colour blind. Assuming that no crossing over took place in prophase I of meiosis, Klinefelter syndrome in Son 1 resulted due to nondisjunction during which one of the following events?
Centromere positions can be mapped in linear tetrads in some fungi. A cross was made between two strains a b and a b and 100 linear tetrads were analysed. The genes a and b are located on two arms of the chromosome. The tetrads were divided into 5 classes as shown below
Class
1
2
3
4
5
a b
a b
a b
a b
a b
a b
a b
a b
a b
a b
a b
a b
a b
a b
a b
a b
a b
a b
a b
a b
Linear tetrads
15
29
52
2
2
Based on the above observation, the following conclusions were drawn:
A. Class 1 is a result of a cross over between a' and the centromere
B. Class 2 is a result of a double crossover involving 3 strands between 'a' and the centromere
C. Class 5 is a result of a double crossover between 'a' - centromere, and 'b'- centromere, involving three strands
D. Class 4 is a result of a double crossover, involving all the 4 strands
Which one of the following options represents all correct statements?
A To transgenic plant contains two unlinked copies of the T-DNA of which, one is functional and the other is silenced. Segregation of the transgenic to non- transgenic phenotype would occur in a (i) ratio in progeny obtained by backcrossing and in a (ii) ratio in F1 progeny obtained by self-pollination.
Fill in the blanks with the correct combination of (i) and (ii) from the options given below:
