I grew a bunch of Zucchinis in a green house. As it was getting dark I grabbed them all and went into a house to cook them up on a stove. After cooking them all I realised I should have saved at least one to cut open for seeds. I equipped a knife and was surprised to see I had the option to use knife to get seeds from zucchini. I held RT as instructed, the animation played, the zucchini disappeared but I got no seeds.