I have dry hair so i need to use some hair Gel .. its strong hold .. Can these hair gels get my hair white , because i have noticed many more white hairs after i started using gel?

There are no ingredients in any hair gel that can turn your hair white. Melanin is what gives hair its color and genetics determine when it will turn white. It could be that the gel you're using is just making it more noticable to you. Some products can make your natural color appear a little darker, like when your hair is wet, and that might make the white hair stand out more. You could try a different product on your hair avoiding the ones with strong hold. See if that helps.

You didn't say- is it actually "gray" hair or does the product leave a white film?
I have used a product before that made my hair white on the ends. It clung to the breakage, which it was supposed to do but it wasn't supposed to be white, LOL! Did the same thing to my son's hair. So, I guess if that's the problem- find another product. Does it say "silk" on the bottle? That's what mine was.