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UPSC Prelims 2024 · Agriculture · Crops and Where They Grow
Consider the following plants: 1. Groundnut 2. Horse-gram 3. Soybean. How many of the above belong to the pea family?
- (a) Only one
- (b) Only two
- (c) All three
- (d) None
Show the answer and explanation
Answer: (c) All three
Groundnut, horse-gram and soybean all belong to the pea family (Fabaceae / legumes).
The idea
The pea family (Fabaceae) = legumes. They carry pods, and Rhizobium bacteria in their root nodules fix atmospheric nitrogen — so they enrich the soil.
Legume root nodules → Rhizobium fixes N₂ → richer soil for the next crop
Why the others are wrong
(a) Picks only the obvious pulse (horse-gram). Groundnut and soybean are also pod-bearing legumes — used as oilseeds, but family is decided by the plant, not its use.
(b) Usually drops groundnut because its pod grows underground. It is still a legume — the peg pushes the pod into the soil after flowering.
(d) Assumes “oilseed” and “pulse” are separate families. Soybean and groundnut are oilseeds by USE but legumes by FAMILY.
The trap
Groundnut and soybean are “oilseeds”, so people don’t think of them as pulses. A crop’s USE (oil) is different from its FAMILY (legume).
🔒 Legumes: all pulses + groundnut + soybean + horse-gram + moong + cowpea. They fix nitrogen.
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