How and which different varieties of cabbage are developed from the wild variety of cabbage by the farmers?

Explanation

Varied organisms are evolved from common ancestor.
From wild variety of cabbage several different varieties of plants are cultivated by artificial selection. Before two thousand years farmers were an edible variety of producing wild cabbage plant. Its closely arranged leaves at short distances were used as food.
Some farmers have obtained variety of cabbage in which flower development was arrested and then they were cultivated as broccoli.
Some farmers have obtained variety of cabbage having sterile flowers and they were cultivated as cauliflower.
Some farmers selected the swollen portion of the wild cabbage and developed new variety called Kohlrabi from this.
Some farmers have developed a few larger leaves of the wild cabbage as a new variety called Kale, a leafy vegetable.
All these varieties are apparently quite different individually from the ancestral wild cabbage.