RAS question
With reference to climate-smart agriculture technologies, which of the following is CORRECTLY matched? (Variety/Technology -- Feature)
Correct answer: (A) Sub1 rice variety -- Carries the Sub1A gene that confers tolerance to submergence/flood for up to 17 days.
Sub1 rice is correctly matched with the Sub1A gene because it gives rice tolerance to complete submergence or flooding for up to 17 days.
Explanation
Option A is correctly matched. Sub1, especially the Sub1A allele discovered in the FR13A rice landrace, forms the basis of flood tolerance in rice. IRRI's account supports this: scientists knew FR13A could survive complete submergence, identified the key DNA region as SUB1, and later transferred SUB1A into widely grown modern rice varieties without changing the traits that made those varieties useful. Flood-tolerant versions of IR64, Swarna and Samba Mahsuri were tested at IRRI, where Sub1 plants recovered after complete submergence and outperformed their non-Sub1 counterparts. Hence the match in option A captures the core climate-smart technology: breeding a flood-tolerance gene into popular rice varieties for flood-prone rice ecosystems.
Why the other options are wrong
- (B) Swarna Sub1 is wrong because it is a flood-tolerant rice variety, not a drought-tolerant wheat variety developed by CIMMYT.
- (C) SRI is wrong because it avoids continuous flooding and instead uses alternate wetting and drying.
- (D) Zero Tillage wheat is wrong because it reduces fuel and machinery costs and improves soil carbon sequestration, rather than increasing costs with no soil-carbon benefit.
Concept
This tests climate-smart agriculture through stress-tolerant crop varieties and resource-conserving practices. It recurs in RAS because agriculture questions often ask candidates to distinguish real adaptation technologies from plausible but reversed feature statements.