We don’t see farmers today getting farming advice from the church. They get it from other farmers.

uh, they get it from the ag departments from their state/local universities. They didn’t have universities back then.

Also, while most farmers probably knew not to do hybrids back then, the consequences of loosing an entire year’s harvest of a stable crop would mean famine for the tribe. You can’t just ask for half of a neighboring village’s seed stock. It was important enough to make it a sin.