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Phaseolus vulgaris (Green beans, Large white beans, Flageolet, Black bean, Borlotto bean, Red kidney bean, Cannellino bean, Sugar bean)

Life > eukaryotes > Archaeoplastida > Chloroplastida > Charophyta > Streptophytina > Plantae (land plants) > Tracheophyta (vascular plants) > Euphyllophyta > Lignophyta (woody plants) > Spermatophyta (seed plants) > Angiospermae (flowering plants) > Eudicotyledons > Core Eudicots > Rosids > Eurosid I > Fabales > Family: Fabaceae > Subfamily: Papilionoideae > Genus: Phaseolus

Phaseolus vulgaris (Green beans, Large white beans, Flageolet, Black bean, Borlotto bean, Red kidney bean, Cannellino bean, Sugar bean)

Phaseolus vulgaris, Grahamstown, Eastern Cape, South Africa. [photo H.G. Robertson, Iziko ]

Phaseolus vulgaris (Green beans, Large white beans, Flageolet, Black bean, Borlotto bean, Red kidney bean, Cannellino bean, Sugar bean)

Kidney beans. [photo H.G. Robertson, Iziko ]

Phaseolus vulgaris Grahamstown, Eastern Cape, South Africa. [photo H.G. Robertson, Iziko ]

Sugar beans. [photo H.G. Robertson, Iziko ]

Haricot beans. [photo H.G. Robertson, Iziko ]

Originate from Central and South America. The earliest archaeological evidence of domesticated bean seeds is from 7500 years ago at a site in mountainous northern Peru.

Phaseolus vulgaris originates from South and Central America where its wild forms are found over a wide discontinuous range from Argentina to Mexico. There are morphological and biochemical differences between the populations in Mexico and those in South America and in fact hybrids between plants from the two regions are largely sterile. This sort of evidence is good enough to place them in different species but this has not been done because they both gave rise either separately or in combination to the various cultivars of beans now placed in Phaseolus vulgaris. Analysis of seed proteins, isozymes and differences in morphology of P. vulgaris cultivars show that this species has six major races that are the result of six separate domestication events between Mexico and the southern Andes. There has been some subsequent hybridisation between these races to produce further varieties. Therefore to split up Phaseolus vulgaris cultivars between the two wild species is likely to lead to a confusing nomenclature but perhaps this is not a good enough reason for not doing so..

Domesticated bean seeds can be distinguished from those of wild plants because they are larger. The earliest archaeological evidence of domesticated bean seeds is from 5500 BC at a site in mountainous northern Peru. At this time there was no domesticated maize and no pottery making. The earliest evidence of bean seeds from archaeological sites in Mexico is from 5000 BC. So by this time beans had been independently domesticated in the two regions. Despite these early beginnings, domesticated beans took a long time to spread more widely through North and South America and to be grown as a staple crop. However, by the 1400's beans had caught up with maize and become a staple crop through most of the Americas. By the mid-1500's, cultivars of P. vulgaris were being grown in Europe. Beans were introduced into Africa probably by the Portuguese and spread into the interior faster than European exploration. 

The pods of green beans are cooked as a vegetable. Other varieties yield beans that are often stored dry and then rehydrated and cooked as vegetables. Raw beans contain protease inhibitors and lectins which can interfere with digestion. The lectins prevent absorption of nutrients in the intestine. However, these are destroyed by cooking.

Ecological interactions

Not covered here other than to mention Phakopsora pachyrhizi (Asian soybean rust), which infects about 95 species of legume including Phaseolus vulgaris.

References

  • Sauer, J.D. 1993. Historical geography of crop plants - a select roster. CRC Press, Boca Raton, Florida.

Text by Hamish G. Robertson 


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