All cultivated crops / plants were domesticated from their wild species. However, the exact time and place of origin and the true ancestry of many crops are still as highly speculative as the origin of man. Man has domesticated some crop species that met his needs before the dawn of recorded history.

Most of the domesticated crops were introduced into new areas far from their centers of origin by migrating human populations in prehistoric as well as in recorded times. As a result, both indigenous and introduced crops are grown everywhere in the world.

1) Centres of Origin of Cultivated Crops

The centres of origin of both agriculture and culture were in populated areas favored by a more equitable climate.

Nicolai Ivanovic Vavilov (1926) concluded that a centre of origin was characterized by dominant alleles while towards the periphery of the centre, the frequency of recessive alleles increased and the genetic diversity decreased.

He reported the following centres of origin:

China
India/Indo-Malayan
Central Asia
Near East
Mediterranean Sea coastal and adjacent regions
Ethiopia or Abyssina
South Mexico and Central America
South America (Peru, Ecuador, Bolivia, Chile etc.)

2) Contribution of the Different Centres of Cultivated Crops

The following are the important crops that originated in the different centres. Some crops may have two centres of origin, (primary and secondary centres of origin).

2a) Chinese centre

China is one of the richest centres of crop origin contributing to many important crops such as Brassica campestris and related species, Camellia sinenses, Colocasia esculenta, Corchorus sinensis, Glycine max, Panicum miliaceum, Raphanus sativus and Setaria italica. It is secondary center for Oriza sativa spp. Japonica, Zea mays and other crops.

2b) Indo-Malayan Centre

This region is important for such crops such as Cocos nucifera, Colocasia esculenta, Dioscoria app., wild Oryza spp. and Saccharum officinalis.

The Historical Origin of Cultivated Crops

2c) Indian Centre

Important crops from this center include; Oryza sativa, Phaseolus mungo, Piper spp., Saccharum sinensis, Vigna sinensis and Cucurbita sativa.

2d) Central Asia Centre

Among the important crops of this center include; Allium cepa, Daucus carota, lathyrus sativa, Spinacea oleracea and vicia faba.

2e) Near Eastern Centre

This is the center of origin of Brassica olearacea, Hordeum Vulgare, Lens esculanta, Medicago spp., Secale spp., Triticum spp., Vicia sativa and Vitis vinifera

2f) Mediterranean Centre

Many field crops have been domesticated in this region; Avena spp., Beta vulgaris, Brassica napus, B. oleracea, Lathyrus spp., Olea europaea, Raphanus sativas, Trifolium spp. Vitis vinifera.

2g) Ethiopian or Africa Centre

Brassica juncea, Ceiba pentandra, Coffea spp., Cola spp., Cucumis spp., Gossypium., Hibiscus spp., Lablab purpureaus, Oryza spp., Pennisetum spp., Phoenix spp., Ricinus communis, Sesamum indicum, Setaria spp., Sorghum bicolor and Vigna unguiculata are all important crops of Africa centre of crops origin.

2h) Central American and Mexican Centre

Few important crops were domesticated in this region; Agave spp., Capsicum spp., Gossypium spp., Ipomoea batatas, Phaseolus spp. and Zea mays.

2i) South American Centre on Cultivated Crops

This centre account for most of the tuberous crops such as Solanum spp., Oxalis tuberose and Ullucus tuberous. Amaranthus spp., Arachis hypogaea, Capsicum spp., Lycopersicum spp., Lupinus spp., Manihot esculenta, Nicotina spp., Phaseolus spp., Solanum spp. and Theobromw cacao all have their origin from this centre. This centre also serves as secondary centre of diversity of Zea mays.

Read Also: Systems of Crop Production