Scientific name – Phaseolus lunatus
English common name – Lima bean; also known as butter bean, Madagascar bean, and Burma bean
Asian common names – Burmese: htawbat pe Chinese: cai dou Japanese: rai mame Korean: 리마콩 Malay: kacang China; kekara (Indonesia) Thai: ถว่ั ราชมาษ thua rachamat
Vietnamese: - Photo: ECHO Asia staff
Variety – Burma Red: Climbing lima bean with indeterminate production. Produces medium-sized red beans.
General description and special characteristics – A widely cultivated pulse crop in Myanmar, this annual is better adapted to the poor soils of the lowland humid tropics and gives better yields than common beans (Phaseolus vulgaris). Varieties can be climbing (2-4 m or 6.6 ft) length or bush (heights up to 0.9 m or 3 ft) types. Pods range in length between 5-12 cm (2-5 in). Among limas, both short-lived and long-lived perennials are grown.
Crop uses (culinary) – Immature sprouts, leaves, and pods are consumed in Asia with young leaves and pods steamed and green shelled beans cooked as a vegetable. Dried white-seeded varieties are sold as butter beans in Europe. In Japan, beans are fermented and made into tempeh kara. As a pulse, lima beans contain approximately 20% protein and require a longer cooking time than other pulses like mung bean. Dark colored beans are bitter-tasting and should be thoroughly boiled and the cooking water discarded to avoid consuming toxic amounts of cyanide-producing glucosides. Raw seeds may cause poisoning.
Crop uses (soil improvement) – Lima bean helps restore soil fertility by shedding its many leaves that decay and enrich the soil. It is also used as a green manure and cover crop to prevent soil erosion from heavy rainfall in rubber plantations. AVRDC cites the use of lima as a cover crop or green manure in Malaysia. The ECHO Seed Bank in Florida offers the “Seven Year Lima” variety which can smother and suppress weeds while providing continual forage for animals, beans for human consumption, a dense perennial cover crop for tropical dry regions, and a green manure that adds nitrogen to the soil.
Crops uses (livestock production) – Dried vines may be used as animal fodder. There are some reports of fresh green foliage being poisonous (Herklots), but other accounts of vines being fed to cattle in Malaysia and Indonesia and young leaves used for hay in Madagascar (AVRDC).
Seasons of production – Planting is usually done at the beginning of the rainy season. However, lima bean requires a dry period for seeds to mature. Heavy rainfall during flowering period may reduce fertilization of flowers.
Length of production and harvest period – Influencing periods of production, lima bean contains both day-neutral genotypes that flower with day lengths of 9-18 hours and short-day genotypes that require day lengths of 11-12.3 hours for flowering. Pods of early-maturing cultivars may be harvested about 60-110 days from sowing but the larger-seeded cultivars may take 180-240 days to reach maturity and may be harvested up to about 330 days after sowing (Bunch 2007).
Pollination – Ashworth (1991) reports that all varieties of limas will cross with each other. Therefore, different varieties of limas must be isolated by at least one mile (1.61 km) to ensure seed purity. Or if various varieties are grown in proximity, blossom bagging or plant caging is required for pure seed production and saving.
Plant spacing – Suggested plant spacing for pole varieties are 40-50 cm (15.7-19.7 in) x 50-100 cm (19.7-39.37 in). For bush varieties, 10-20 cm (3.94-7.87 in) x 50-100 cm (19.7-39.37 in) is recommended (AVRDC).
Production methods – Vining varieties require support (trellises, fences, etc.).
Environmental conditions for production – Elevations for production range from sea level to 2400 meters (7,874 ft) in the tropics and sub-tropics.
Soil requirements – Well-adapted to lowland tropics, especially the highly leached, infertile soils of the more humid regions, but prefers well-drained, well-aerated neutral (pH 6-7) soils.
Pests and diseases – Serious pests are leaf diseases such as cercospora and rust, as well as root-knot nematodes, viruses, and insects such as leaf hoppers and pod borers.
Seed saving – Ashworth (1991) states that lima pods left to dry on the vine will shatter easily; therefore the dry pods must be picked carefully. Where bean weevils are a problem, pick the pods when fully mature but not yet dry and spread the pods out to dry quickly before shelling the seeds. After the seeds are fully dry, it is recommended to freeze the seeds for 48 hours to kill weevil eggs in the seeds. If stored in cool, dry, dark conditions, lima beans will maintain 50% germination.
References –
Ashworth, S. 1991. Seed to Seed. Decorah, Iowa: Seed Savers Exchange, Inc.
AVRDC. Know You IVs: Lima Bean. IV Leaflet No. 3. AVRDC, The Word Vegetable Center. Available: http://203.64.245.173/iv_sea/publications/limabean.pdf.
Bunch, R. 2007. Changing our Understanding of the Fertility of Tropical Soils. Phaseolus lunata. FAO - Food and Agriculture Organization of the UN. Available: http://ecocrop.fao.org/ecocrop/srv/en/cropView?id=1666.
Purseglove, J. W. 1968. Tropical Crops: Dicotyledons. Essex, U.K.L Longman Group Ltd.