Phaseolus spp. beans are valued grain legumes or pulse crops of worldwide importance in terms of human and animal consumption. Common bean (Phaseolus vulgaris L.) is the most important Phaseolus spp. worldwide, while the runner bean (Phaseolus coccineus L.) is the third, right after lima bean (Phaseolus lunatus L.). P. vulgaris beans come in an enormous variety of shapes, sizes, and colors, from pinto to pink to black to white. Despite this diversity, wild and domestic beans belong to the same species, as do all of the colorful varieties ("landraces") of beans. The main difference between wild and cultivated beans is, well, domestic beans are less exciting. There is a significant increase in seed weight, and the seed pods are less likely to shatter than wild forms: but the primary change is a decrease in the variability of grain size, seed coat thickness and water intake during cooking. Domestic plants are also annuals rather than perennials, a selected trait for reliability. Despite their colorful variety, the domestic bean is much more predictable. Common Names for Common bean are bean, French bean, haricot bean, salad bean, snap bean, string bean, kidney bean, runner bean, scarlet runner bean, multiflora bean, butter bean, garden bean, green bean, bush bean, navy bean, pole bean, flageolet bean, Anasazi beans, black beans, northern beans, pinto beans, Cannellini beans, scarlet bean, Judión or Spanish bean. Some varieties of the common bean are grown only for the dry seeds, some only for the edible immature pods, and others for the seeds, either immature or mature. Varieties differ greatly in size, shape, colour, and fibrousness or tenderness of the immature pods. In general, varieties grown for dry mature seeds produce pods that are too fibrous to be eaten at any state of development. The Mesoamerican region is considered the center of origin and diversification of beans (Phaseolus spp), cultivated and wild. Two main gene pools, Mesoamerican and Andean associated with these two geographical areas, have been described in wild and cultivated common beans. Genetic diversity or variation between different populations belonging to the same genus resulted from the evolution of crops through the history, in response to different environments and husbandry practices (Fowler, 2008). Genetic diversity of runner bean has been less extensively investigated. The largest set of European landraces, more than 300, was evaluated by cpSSRs and a smaller set was studied also for phenotypic traits. Green beans are classified by growth habit into two major groups, "bush" (or "dwarf") beans and "pole" (or "climbing") beans. All beans are ecologically beneficial as they form a symbiotic relationship between nodules on their roots and nitrogen fixing bacteria called rhizobia. This bacteria adds much needed nitrogen back into soil profiles. Beans also form another symbiotic relationship in their roots with mycorrhizal fungi. The mycorrhizal fungi gain carbon from the host plant and in turn they increase the root surface area allowing for better uptake of water and nutrients, especially slow moving phosphorus. Recently the role of bean in human diet is being focused not only in its protein content but in the functional properties also and some authors have reported that its consumption could contribute to reduce risk of obesity, diabetes, cardiovascular diseases and colon, prostate and breast cancer. These health benefits could be due to the fiber content in the grain but also to antoxidant compounds as the phenolic ones. In this review article on Origin, Domestication, Taxonomy, Botanical Description, Genetics and Cytogenetics, Genetic Diversity, Breeding, Uses, Nutritional Value and Health Benefits of beans are discussed.
