In mung bean, resistance to yellow mosaic virus and powdery mildew were induced by:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Mutation
Option (1) Hybridisation — Incorrect. Hybridisation combines characters of two parents by crossing them; it was not the method used here.
Option (2) Recombination — Incorrect. Recombination reshuffles existing genes during meiosis; it does not create the new resistance.
Option (3) Micropropagation — Incorrect. Micropropagation makes thousands of identical plants by tissue culture; it copies plants without changing their genes.
Option (4) Mutation — Correct. Seeds are treated with chemicals or radiation; plants that show the wanted resistance are selected (mutation breeding).
Note: This question is from Chapter 9, Strategies for Enhancement in Food Production, of the pre-rationalised NCERT book. This chapter is not in the present NCERT book (2026-27). The extract below is from the pre-rationalised edition.
NCERT Extract (Pre-rationalised edition, Chapter 9, Strategies for Enhancement in Food Production):
Plant Breeding for Disease Resistance – “… Mutation is the process by which genetic variations are created through changes in the base sequence within genes (see Chapter 5) resulting in the creation of a new character or trait not found in the parental type. It is possible to induce mutations artificially through use of chemicals or radiations (like gamma radiations), and selecting and using the plants that have the desirable character as a source in breeding – this process is called mutation breeding. In mung bean, resistance to yellow mosaic virus and powdery mildew were induced by mutations.”