UPSC Prelims 2017 GS Paper I · Q45 / 100 General Science medium

With reference to agriculture in India, how can the technique of ‘genome sequencing’, often seen in the news, be used in the immediate future ? 1. Genome sequencing can be used to identify genetic markers for disease resistance and drought tolerance in various crop plants. 2. This technique helps in reducing the time required to develop new varieties of crop plants. 3. It can be used to decipher the host-pathogen relationships in crops. Select the correct answer using the code given below :

  1. (a) 1 only
  2. (b) 2 and 3 only
  3. (c) 1 and 3 only
  4. (d) 1, 2 and 3 ✓ UPSC's answer

Why the answer is (d)

• Genome sequencing reads a crop's entire DNA, revealing genetic markers linked to traits such as disease resistance and drought tolerance (1).

• Marker-assisted selection then lets breeders screen seedlings for desired genes instead of waiting for field trials, cutting the time needed to develop new varieties (2).

• Sequencing both crop and pathogen genomes reveals how pathogens infect hosts and how hosts resist — the host–pathogen relationship (3).

• Hence 1, 2 and 3, option (d).

Why the other options are wrong

(a) 1 only
Statements 2 and 3 are also correct.
(b) 2 and 3 only
Statement 1 on markers is also correct.
(c) 1 and 3 only
Statement 2 on faster breeding is also correct.

Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2017, held on 18 June 2017. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.

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