Planters won't fill and only allow corn

[Farmer20091]

I am not sure why its is happening but I about a week ago any time I try to plant crops the only option I have for seed selection is corn. Also, I can't load the planter with seed. The planter will work using a worker and having the seed setting on "Buy" but it only plants corn. I am not sure exactly when this started happening but it was about 1 week ago.