Enter a modem market place; or visit a bustling shopping mall and the fruits and rewards of modem agriculture will greet you at every turn. A myriad of shops supply reliable and plentiful quantities of high quality food and fibre while others provide the trademark goods and services of a sophisticated, modern society. Most people in modern communities unlike their ancient forebears procure their food and fibre from shops and supermarkets enjoying the efforts of those who through the millennia of time have taken opportunities to select, breed and nurture new plant and livestock types. These opportunities are the fundamental building blocks of modern agriculture