which Pokemon should I use to breed with sceptile so it can an learn grass whistle???
I reccomend Snover, Abomasnow. Snover learns Grass whistle at lv 13 the same with Abomasnow. You could also breed with Bulbasaur and Chikorita line but they must learn it by breeding too. So get a male Snover/Abomasnow to lv 13 but if you have a abomasnow you could just get a heartscale and go to dendimelle. Then breed with a female Treeko/Grovyle/Sceptile. Hope I helped Source Serebii
The quickest way is to breed a female sceptile or any of its pre evolutions with a male snover or a male abomansnow. Snover learns Grass Whistle at level 13.
To get an lv 13 snover to learn Grass whistle, breed abomansnow with a ditto. To get an abomansnow with Grass whistle, just go to the move reminder.
hope I helped!
sources http://pokemondb.net/pokedex/snover
http://pokemondb.net/pokedex/sceptile/egg