I'm sure in most cases the seeds are good enough, but I would also imagine the environment has some effect on vegetable appearance too: qualities of the soil, h

I'm sure in most cases the seeds are good enough, but I would also imagine the environment has some effect on vegetable appearance too: qualities of the soil, how they were planted and cared for, qualities of the sunlight, etc. As an extreme example, you can't get cube watermelons just by planting the seeds of another; you need the box to grow it in too.