Origins and history
The common bean originating from South America (Peru, Colombia) is widespread above all in Asia and in the Mediterranean basin. It was imported, following the discovery of America, in Europe where there were only beans of species belonging to the genus Vigna, of sub-Saharan origin: the beans of the genus Phaseolus have spread everywhere, supplanting the group of the ancient world, as they have proved more easy to grow and more profitable
Appearance and properties
An annual plant with a rapid development, the beans are divided into dwarfs, more suitable for cultivation in the open field, and vines that lend themselves well to the cultivation of hortens where the harvest is gradual and manual.
The fruit is a legume of very variable shape, color and size: compressed or cylindrical, green or yellow, 60 to 220 mm long, straight or curved. An important anatomical feature is the presence or absence in the pod of fibrous tissues which determine the type of use. There are thus two types of pod structure:
- Pods whose valves easily separate due to the presence of a fibrous cord along the welding lines (thread) and have layers of fibrous tissue (parchment) within each valve: their use is by seed;
- Pods without thread and without parchment and which are therefore tender and fleshy for a long time (mangiatutto or croissant beans, more commonly called "beans").
Given its tropical origin, the bean is demanding in terms of heat; in fact the minimum temperature to have an acceptable yield is 13-14° C. It is also very afraid of drought which can compromise the quality and yield of the crop.
In small-scale cultivation, fresh green beans and pods are harvested by hand in scalarmene, while the dry grain bean plants are grubbed up by hand when the pods have begun to dry out, they are left to complete the drying in the field to then be shelled
In large crops, all types of harvesting can be mechanized as long as the plants are dwarf and mature at the same time.
Currently there are 40,000 bean species, present in the world's gene banks, but only some of these are actually used for food.