A type of resistance in which a series of different cultivars of the same crop are infested with a series of different insect biotypes of same species show a differentia interaction is known as________?

Mostly the salt of calcium and Magnesium can not cause ________?

Which method of irrigation is possible under the economical conditions of Pakistan ________?

Labour force engage in Agriculture in economically developed nations?

Approximate quantity of milk requires to get 1 Kg of butter is ________?

A channel artificially constructed for water conveyance of appreciable quantities with no problem of silting and scouring is called ________?