What achievements of agriculture in England in the 19th century did Charles Darwin pay special attention to?

What achievements of agriculture in England in the 19th century did Charles Darwin pay special attention to? What scientific interests were the reasons for this?

1. By that time, English farmers had bred many breeds of dogs, pigeons, cattle and chickens, intensively breeding new varieties of cultivated plants.
2. Proponents of species constancy argued that every variety and breed has its own wild ancestor, while Darwin believed that this is not the case. For example, he proved that all breeds of chickens come from one wild bank chicken, cattle from two types of wild tours, and so on.