Question

Why wind and water pollinated plants do not produce nectar?

Answer 1

Water and wind being the pollen carriers of such flowers and not insects, there is no evolved system to attract insects for pollen and nectar. Flowers having colors and nectar would have been a redundant arrangement anyway if pollens are not being transmitted through insects but rather by water and wind. Obviously, nature did not evolve this process among such flowers.

Answer 2

Wind nd Water pollinated flowers do not produce nectar because they don't have to attract water and wind toward them..

Wind nd Water will flow nd pollination will occur ...
that's the reason,
the wind nd Water pollinated flowers are not so attractive means they don't have much large and colourful petals, nice smell ,nectar etc.

whereas the insect pollinated flowers produce nectar and they have large and beautiful petals,sweet smell etc. to attract insects towards them...