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Brassica rapa var. rapifera
|DESCRIPTION: A biennial herb with swollen tuberous white-fleshed taproot, which may be globular or flattened and lacking a neck; leaves light to medium green, hairy or bristly, stalked, lyrate-pinnatifid, 30-50 cm long, stem-leaves sometimes glaucous with clasping base; flowers bright yellow, sepals spreading: petals 6-10 mm long, those in anthesis close together and commonly overtopping the unopened buds; outer 2 stamens curved outwards at base and much shorter than inner stamens; fruit 4-6.5 cm long, with long tapering beak, on divaricate-ascending pedicels 3.2-6.5 cm long; seeds blackish or reddish-brown, 1.5-2 mm in diameter. USES: Turnips are one of the most commonly grown and widely adapted root crops, as a general farm crop or home-garden crop. Roots are eaten raw or cooked as a vegetable and the tops used as a potherb such as spinach. Roots also grown for feeding to livestock during fall and winter. The powdered seed is said to be a folk remedy for cancer. The root when boiled with lard is used for breast tumors. The stems and leaves are said to be a remedy for cancer, while a salve derived from the flowers is said to help skin cancer. The root starch can be used to produce bio-ethanol. KILLING T.: Unhardened plants can survive -4°C, while fully-hardened spring types can survive -10 to -12°C, and hardened winter turnip can survive short periods of exposure to -15 to -20°C. GROWING PERIOD: Biennial, usually grown as an annual, growing 40-80 days for harvest as vegetable, and 55-80 days for harvest of the root. COMMON NAMES: Turnip, turnip rape, navet, nabo forrajero, nabo rutabaga, kohl-rube, koolraap. FURTHER INF.: Scientific synonyms: B. campestris var rapa L., B. campestris var rapifera L. Turnip is native of central and southern Europe. Cultivated in Europe for over 4000 years, probably native to central and southern Europe, now spread throughout world, including most parts of the tropics. In the tropics, it is suitable for elevations above 1000 m and only very few cultivars can be grow at low elevations. Turnip is basically a cool climate crop, resistant to frost and mild freezes. Temperatures below 10°C cause bolting. Turnips do well in deep, friable, highly fertile soil with pH of 5.5-6.8; sandy loams are used for early markets roots and greens. Their short growing season makes them very adaptable as a catch crop. Ranging from Boreal Moist to Rain through Tropical Thorn to Moist Forest Life Zones, it is reported to tolerate an annual precipitation of 3500 to 4100 mm, an annual temperature of 3.6 to 27.4°C and a pH of 4.2 to 7.8. Light shade is sometimes beneficial for plants grown for leaf consumption and the plant is drought-resistant. Yields are normally between 20-25 t/ha or 2-2.5 kg/m2. 2000-2500 liters of ethanol have been obtained in research trials. Cross-pollination, by various insects, is necessary for good seed production. Seed is sown thinly in spring, summer or autumn in drills at a seed rate of 1.1-2.2 kg/ha. Seedlings then thinned to stand 5-15 cm apart in rows 0.3-0.9 m apart. Cultivate shallowly for weed control. Add lime to soil to correct pH to 5.5-6.8. Only light applications of fertilizer are justified, such as 450-675 kg/ha of 4-12-4. When turnips are seeded as an autumn crop following a crop that has been well fertilized, no additional fertilizer may be necessary. Seed may be broadcast on fertile, well-prepared seedbeds where weed control will not be difficult. Turnips may be intercropped with maize, and as such they are shade-tolerant, or they may be used as a catch crop after early vegetables. It is not advisable to grow turnips after a root crop. Good rotation helps to control diseases. Best grown after clover, beans, peas or grass crop.
Roots may be harvested in 45-80 days. They are harvested for bunching when 5 cm in diameter, and for topped turnips when 7.5 cm in diameter. Turnip greens may be harvested when plants are young and tender. For early spring market, turnips are pulled, washed, their tops left on, tied in bunches, and marketed. Flavor and texture are not improved by storage. They should not be left in the ground where temperatures near freezing occur; in milder areas they may be left in field until desired. They may be stored in pits or piles, in well-drained soils. Piles should not be more than 2.6 m wide nor more than 2 m deep to prevent heating at the center. For good aeration, wooden chutes are inserted at intervals of 2.5-3 m in the pile. A ditch is dug around the base of pile for water runoff. Alternate layers of straw and soil are used as covering for pit storage. For indoor storage, crates or small piles laid on earth cellar floors are satisfactory. Small quantities of turnips may be stored in a cool cellar and covered with moistened clean sand to keep them from drying out. Storage temperature in a cellar or in a cold storage room should remain between 0° and 1.5°C, with a relative humidity of 90-95%.
Per 100 g, the root is reported to contain 30 calories, 91.5 g H2O, 1.0 g protein, 0.2 g fat, 6.6 g total carbohydrate, 0.9 g fiber, 0.7 g ash, 39 mg Ca, 30 mg P, 0.5 mg Fe, 49 mg Na, 268 mg K, a trace of b-carotene equivalent, 0.04 mg thiamine, 0.07 mg riboflavin, 0.6 mg niacin, and 36 mg ascorbic acid. Per 100 g, the leaf is reported to contain 23 calories, 92.7 g H2O, 1.9 g protein, 0.2 g fat, 4.6 g total carbohydrate, 1.0 g fiber, 0.6 g ash, 168 mg Ca, 52 mg P, 2.6 mg Fe, 78 mg Na, 420 mg K, 1330 mg b-carotene equivalent, 0.10 mg thiamine, 0.18 mg riboflavin, 0.7 mg niacin, and 47 mg ascorbic acid. Seed oil contains large amount of erucic, linoleic, and linolenic acids.
|Duke J A. 1983. Handbook of Energy Crops.
Izqueirdo J 2005 (pers. comm.)
Roecklein J 1987 pp 504 [USE]
Hartmann T 1981 pp 587 [USE, TEMP, KTEMP, DEP, TEXT, FER, DRA]
Tindall H 1983 pp 129-130 [LIG, RAIN, DRA, PH, TEXT]
Purseglove J 1974 pp 95 [USE]
Janick J 1991 pp 302
Rice R 1990 pp 214-215 [LIG, RAIN, DRA, PH]
Hockings E 1961b pp 390-391 [USE, TEXT, FER]
Westphal E 1989 pp 61-64 [USE, TEMP, KTMP, PHO, RAIN, DRA, PH, SAL]