11 - Common bean (Phaseolus vulgaris)
Published online by Cambridge University Press: 05 June 2012
Summary
Taxonomy
The taxonomy of Phaseolus has been reviewed by Debouck (1991). The genus, of New World origin, is in the tribe Phaseoleae and is tentatively regarded as including 55 species, of which five are cultivated:
P. vulgaris L., common bean
P. coccineus L., scarlet runner bean
P. lunatus L., Lima bean
P. acutifolius A. Gray, Tepary bean
P. polyanthus Greenman, year-bean
All are diploid (2n = 2x = 22). There are some genetic affinities between the species: crossing experiments suggest that P. vulgaris, P. coccineus and P. polyanthus are closely related, but there is little compatibility between P. lunatus and other species (Debouck, 1991).
Classification of types with P. vulgaris is based on determinacy of the main axis, growth habit, crop duration and seed characteristics (Voysest & Dessert, 1991). Plants may be erect (‘bush’ beans), semi-climbing or climbing; crop duration may vary from 75 days for an early bush type to 270 days for a late climbing type in a cool climate.
The seeds of the common bean are highly variable and consumer preferences are very refined, particularly in Latin America (Voysest & Dessert, 1991). The CIAT classification is based primarily on colour (nine groups), secondarily on size (three groups), and also on shape (round, elongated or kidney). Voysest & Dessert list 66 individually named market classes for seed, distinguished by colour, size and shape.
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- Information
- The Ecology of Tropical Food Crops , pp. 208 - 224Publisher: Cambridge University PressPrint publication year: 1995