rice
穜 centers on rice as a crop, specifically a late-ripening variety. The meaning is narrow and agricultural.
穜 combines 禾 (grain plant) with 童, which likely contributes the sound. The character is associated with a type of rice, but the exact historical development is uncertain.
The grain radical 禾 beside 童 suggests a child-like rice plant that matures late. Picture a rice field where the 穜 variety takes longer to grow, like a child slowly reaching adulthood.
For トウ, imagine a toe poking out of a rice paddy, checking if the late-ripening rice is ready: toe -> トウ.