Tuber bean

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Tuber bean
Eurosiden I
Order : Fabales (Fabales)
Family : Legumes (Fabaceae)
Subfamily : Butterflies (Faboideae)
Genre : Yam beans ( Pachyrhizus )
Type : Tuber bean
Scientific name
Pachyrhizus tuberosus
( Lam. ) Blast.

The tuber bean ( Pachyrhizus tuberosus ) is a type of plant from the genus of the yam bean ( Pachyrhizus ). The original home is in northern South America . It is grown in South America, Asia, and Africa for its edible tubers and seeds.


The tuber bean is a vigorous, perennial herbaceous climbing plant with stems up to 7 meters long . However, it is usually grown as an annual plant because the whole plant is harvested because of the tubers and then re-sown in the following year. It forms starchy root tubers as underground storage organs. The leaves are pinnate in three parts. The termial blade is rhomboid, the two side blades are asymmetrical. The leaf margin is smooth or only slightly angled, the side edges are slightly sloping to each other.

In groups of two or three flowers are usually in groups along the upper half of a very long, racemose inflorescence . The calyx has a length of 1 cm and is hairy with attached, rust-brown trichomes . The crown is white or yellow in color, 1.5 to almost 2.0 cm long, the auricles at the base of the flag stand upright. The shuttle is almost straight, only slightly curved. The stylus is somewhat curled and flattened at the tip.

The legumes are up to 20 cm long, barely 2 cm wide and have a triangular, up to 3 mm long beak. The kidney-shaped seeds are relatively large and mostly red.

The number of chromosomes is 2n = 22.


Individual evidence

  1. Pachyrhizus tuberosus at In: IPCN Chromosome Reports . Missouri Botanical Garden, St. Louis