Question

In rajasthan why are course grains cultivated in place of paddy??

Answer 1

because paddy needs high water avaleblity approximately 75 -100 cm but in rajsthan there is always a problem of water scarcity. and course grains doesn't need so much water.
hence course grains are grown in rajsthan instead of paddy

Answer 2

because need a lot of water for irrigation. while the coarse grain don't need much water for irrigation