Phaseolus acutifolius

Phaseolus acutifolius, also known as the tepary bean, is a legume native to the southwestern United States and Mexico that has been grown there by the native peoples since pre-Columbian times. It is more drought-resistant than the common bean (Phaseolus vulgaris) and is grown in desert and semi-desert conditions from Arizona through Mexico to Costa Rica. The water requirements are low. The crop will grow in areas where annual rainfall is less than 400 mm (16 in).

The tepary bean is an annual and can be climbing, trailing, or erect, with stems up to 4 m (13 ft) long. The specific epithet, acutifolius, is derived from Latin acutus 'pointed, acute', and -folius '-leaved'. A narrow leafed, variety tenuifolius, and a broader leafed, variety latifolius, are known. Domestic varieties are derived from latifolius. Observation of "a limited number" of wild specimens suggested that "the flowers concur with the summer rains, first appearing in late August, with the pods ripening early in the fall dry season, most of them in October". The beans can be of nearly any color. There are many local landraces. Beans vary in size but tend to be small. They mature 60 to 120 days after planting.

Other names for this native bean include Pawi, Pavi, Tepari, Escomite, Yori mui, Yorimuni and Yori muni. The name tepary may derive from the Tohono O'odham phrase tʼpawi or "It's a bean". The name for a small bean was recorded in the 17th century, in the now extinct Eudeve language of northern Mexico, as tépar (accusative case, tépari). Names that contain yori in them typically refer to non-native species of beans, since those names mean "non-Indian person's bean".

Tepary beans have been grown by Native Americans for thousands of years; cultivated beans have been found dating to 500 BCE in the Tehuacán Valley in Mexico. Tepary beans appear to have been domesticated in a single event in northern Mexico, based on genetic evidence.

The Sand Papago (Hia C-eḍ O'odham) were mainly hunter-gatherers but cultivated tepary beans and other crops when moisture made it possible for them to do so. In 1912, ethnographer Carl Lumholtz found small cultivated fields primarily of tepary beans in the Pinacate Peaks area of Sonora. In the Pinacate, with an average annual precipitation of 75 mm (3.0 in) and temperatures up to 48 °C (118 °F), Tohono O'Odham and Mexican farmers utilized runoff from sparse rains to grow crops. In the 1980s, author Gary Paul Nabhan visited this area, and found one farm family taking advantage of the first large rain in six years, planting seeds in the wet ground and harvesting a crop two months later. The most successful crops were tepary beans and a drought-adapted squash. Nabhan calculated that the cultivation in the Pinacate was the most arid area in the world where rain-fed agriculture is practiced.

The tepary bean was a major food staple of natives in the Southwestern United States and northern Mexico. In addition to being grown in floodplains, it was often grown alongside squash and corn. Growing these plants together, known as Three Sisters agriculture, enhances their growth and provides more balanced nutrition.

In the United States, the tepary bean was introduced to Anglo farmers in the 19th century by Tohono O'Odham (Papago) farmers.^{[failed verification]} The Native American method of planting in the American Southwest was to plant three to five seeds in hills 6 to 8 feet (1.8 to 2.4 m) apart. Beans were planted in arroyos that had been recently flooded by summer rain.

The tepary bean is traditionally sown at the start of the monsoon season, typically from mid-June to mid-July. With access to irrigation, earlier seeding dates are possible. Seeds are generally planted 2.5–4 cm deep. Row spacing ranges from 30–40 cm in small-scale plantings and 70―80 cm in larger operations. Seeding rates typically vary between 25 and 35 kg per hectare, with approximately 9000 seeds per kilogramm.