Hello aspirant. Usually after 10th, everyone has two choices. To choose maths or computer science that's one. To choose biology. That's second. Since you are interest in agriculture, only after12th completion, you would be able to choose that path. Something like bsc agriculture etc. So for that you can go for maths or biology in your 11th. That is really not a problem. But biology would help more since you get familiar. If you strong and consistent in agriculture, go for biology in your 11th

All the best