Winged bean (Psophocarpus tetragonolobus)
Varieties for Guam Trial Conducted at the
Valley of the Latte Farms, Talofofo, Guam
Joe Tuquero and Glen Takai
Cooperative Extension & Outreach, College of Natural & Applied Sciences, University of Guam
The winged bean, also known as the Goa bean, Four-angled bean, and Dragon bean, is a legume native to New Guinea. It is a commonly grown bean in Southeast Asia and Papua New Guinea, but is usually cultivated as a small-scale crop (Wikipedia, 2017). Winged bean is a climbing perennial plant that looks and grows similarly to the common pole/string/long bean, Phaseolus vulgaris (Fig 1). Pods are distinctly different from those of the common string bean as they resemble a wing/star-like shape. There are many varieties of winged bean varying in length, width, and color (usually green or purple) of pods.
In the Mariana Islands, winged bean is a popular crop, locally known as ‘sigidiyas.’ Many parts of the plant are consumed, including immature bean pods, leaves, and tubers. Locally, immature bean pods are consumed the most as they are used as a fresh, or cooked, vegetable in a wide variety of local dishes. Immature pods for consumption are usually harvested 2-3 weeks after fruit set while they are still tender and not very fibrous.
On Guam, the most popular local winged bean variety is cultivated seasonally or left in the field to grow year-round. Like many winged bean varieties, the popular ‘local green’ variety is a ‘short day’ plant. ‘Short day’ plants usually only produce flowers and fruits when day length (sunlight) periods are less than 12 hours a day (Savonen, 2003). On Guam, ‘short days’ usually occur from October through March (Astronomical Applications Department, 2016). The popular ‘local green’ short day variety can be found in markets November through May (Bamba et al, 2010). Other plants that require longer sunlight in a day (more than 12 hours) to produce flower and fruit are known as ‘long day’ plants (Savonen, 2003). Table 1 displays the average monthly day lengths of Guam.
In recent years, a ‘day neutral’ variety of winged bean has been cultivated on Guam (Quitugua, personal communication, October 21, 2016). ‘Day neutral’ plants can flower and fruit regardless of the length of sunlight throughout the day. Such varieties are virtually unknown to most local producers. Day neutral winged bean varieties will enable local growers to produce winged beans throughout the year.
There are numerous health benefits of winged bean. Fresh, young bean pods contain a good amount of Vitamin C and other minerals and vitamins such as iron, copper, manganese, and calcium. Thiamin pyridoxine (Vitamin B-6), niacin, and riboflavin are also important B-complex vitamins embedded in winged beans (Rudrappa, 2017).
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