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Helianthus annuus L.

Asteraceae
Sunflower

Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.

  1. Uses
  2. Folk Medicine
  3. Chemistry
  4. Description
  5. Germplasm
  6. Distribution
  7. Ecology
  8. Cultivation
  9. Harvesting
  10. Yields and Economics
  11. Energy
  12. Biotic Factors
  13. References

Uses

Cultivated primarily for the seeds which yield the world's second most important source of edible oil. Sunflower oil is used for cooking, margarine, salad dressings, lubrication, soaps, and illumination. A semi-drying oil, it is used with linseed and other drying oils in paints and varnishes. Decorticated press-cake is used as a high protein food for livestock. Kernels eaten by humans raw, roasted and salted, or made into flour. Poultry and cage birds are fond of raw kernels. Flowers yield a yellow dye. Plants used for fodder, silage and green-manure crop. Hulls provide filler in livestock feeds and bedding.

Folk Medicine

Medicinally, seeds are diuretic, expectorant, and used for colds, coughs, throat, and lung ailments. According to Hartwell (1967–1971), the flowers and seeds are used in folk remedies for cancer in Venezuela, often incorporated in white wine. Reported to be anodyne, antiseptic, aphrodisiac, bactericidal, deobstruent, diuretic, emollient, expectorant, insecticidal, malaria preventative, sunflower is a folk remedy for aftosa, blindness, bronchiectasis, bronchitis, carbuncles, catarrh, cold, colic, cough, diarrhea, dysentery, dysuria, epistaxis, eyes, fever, flu, fractures, inflammations, laryngitis, lungs, malaria, menorrhagia, pleuritis, rheumatism, scorpion stings, snakebite, splenitis, urogenital ailments, whitlow, and wounds (Duke and Wain, 1981).

Chemistry

Per 100 g, the seed is reported to contain 560 calories, 4.8 g H2O, 24.0 g protein, 47.3 g fat, 19.4 g total carbohydrate, 3.8 g fiber, 4.0 g ash, 120 mg Ca, 837 mg P, 7.1 mg Fe, 30 mg Na, 920 mg K, 30 mg b-carotene equivalent, 1.96 mg thiamine, 0.23 mg riboflavin, 5.4 mg niacin, and 0 mg ascorbic acid. Seeds contain 25–35% of oil, but cultivars have been bred in Russia with up to 50% oil. Oil contains 44–72% linoleic acid, and 13–20% protein of high biological value and digestibility. Stems and husks are rich in potash. The forage (ZMB) contains 8.8% protein, 2.9% fat, 77.2% total carbohydrate, 30.3g fiber, and 11.1 g ash. Another analysis shows young shoots contain: 13.0% protein, 1.9% fat, 70.3% total carbohydrate, 20.4 g fiber, 14.8 g ash, 1,670 mg Ca, and 370 mg P/100 g. The flowers contain 12.7% protein, 13.7% fat, 64.3% total carbohydrate, 32.9 g fiber, 9.3 g ash, 630 mg Ca, and 80 mg P/100 g. Sunflower oil has a high concentration of linoleic acid, intermediate level of oleic acid, and very low levels of linolenic acid. The saturated acids, palmitic and stearic, rarely exceed 12%, and the minor acids, lauric, arachidic, behenic, lignoceric, eicosenoic, etc. rarely add up to as much as 2%. Tocopherol, or vitamin E, is an important vitamin and natural antioxidant. Sunflower oil is somewhat unique in that the alpha form predominates, with 608, 17, and 11 mg/kg of alpha, beta, and gamma, compared with 116, 34, and 737 respectively for soybean/oil (Dorrell, 1981).

Description

Variable, erect, often unbranched, fast-growing, annual herb; stems 0.7–3.5 m tall, hirsute; leaves alternate, ovate, long-petroled, lamina with 3 main veins, 10–30 cm long, 5–20 cm wide, apex acute or acuminate, lower leaves opposite and cordate; flowering head terminal on main stem, 10–40 cm in diameter, rotating to face the sun, sometimes drooping, heads on lateral branches smaller; outer ray flowers neuter with yellow ligulate corolla, disc florets numerous, spirally arranged, perfect; ovary inferior with single basal ovule; achenes obovoid, compressed, slightly 4-angled, variable in size and coleo, seldom less than 1 cm long, usually from 1–1.5 cm long, full-colored or striped. Taproot strong, penetrating to depth of 3 m and with large lateral spread of surface roots. Fl. late summer and fall; fr. fall.

Germplasm

Reported from the North American (and secondarily, the Eurosiberian) Center of Diversity, sunflower, or cvs thereof, is reported to tolerate disease, drought, frost, fungi, high pH, laterite, limestone, low pH, mycobacteria, photoperiod, poor soil, rust, salt, sand, smog, virus, weeds, and waterlogging (Duke, 1978). Botanically, the sunflower is treated as the following subspecies: ssp. lenticularis in the wild sunflower; ssp. annuus is the weedy wild sunflower; and ssp. macrocarpus is cultivated for edible seeds. Cultivars are divided into several types: Giant types: 1.8–4.2 m tall, late maturing, heads 30–50 cm diam., seeds large, white or gray, or with black stripes; oil content rather low; ex. 'Mammoth Russian'. Semi-dwarf types: 1.3–1.8 m tall, early maturing, heads 17–23 cm diam., seeds smaller, black, gray or striped; oil content higher; ex. 'Pole Star' and 'Jupiter'. Dwarf types: 0.6–1.4 m tall, early maturing, heads 14–16 cm diam., seeds small, oil content highest; ex., 'Advance' and 'Sunset'. Gene centers are in the Americas, with genuine resources for resistance in southern United States and Mexico. Two types of male sterility are known. Although sunchoke is the name given to the hybrid with the jerusalem artichoke, much of what is sold as sunchoke in the United States is, in fact, straight Jerusalem artichoke. (2n = 34)

Distribution

Native to western North America, sunflower is the only important crop to have evolved within the present confines of the United States. Early introduced to Europe and Russia, the species has now spread to countries both tropical and temperate.

Ecology

Sunflowers are grown from the Equator to 55° N Lat. In the tropics, they grow better at medium to high elevations, but tolerate the drier lowlands. They thrive wherever good crops of corn are grown, Young plants withstand mild freezing. Plants are intolerant of shade. As sunflowers have highly efficient root systems, they can be grown in areas which are too dry for many crops. Plants are quite drought-resistant except during flowering. In South Africa, reasonable yields have been obtained with 25 cm of rainfall by dwarf cultivars. Giant types require more moist conditions. Crop may be grown on a wide range of soils, including poor soils, provided they are deep and well-drained. Plants are intolerant of acid or waterlogged soils. Ranging from Boreal Moist through Tropical Thorn to Wet Forest Life Zones, sunflower tolerates annual precipitation of 2–40 dm (mean of 195 cases 11.4), annual temperature of 6–28°C (mean of 194 cases = 19.6), and pH of 4.5–8.7 (mean of 121 cases = 6.6) (Duke 1978, 1979)

Cultivation

Seed, harvested at 12% moisture content and stored, will retain viability for several years. Sunflower production may be adapted to mechanized or unmechanized societies. Propagation is always by seed. Plant with corn or beet planter, 2.5–7.5 cm deep, spaced 0.2 m apart in 0.6–0.9 m rows; seed rate of 5.6 kg/ha, giving about 62,500 plants per ha. May be planted earlier in spring than corn since plants are more tolerant to frost. Early weed control is an important factor in yield, so cultivate lightly in early stages of crop. Sunflowers respond well to a balanced fertilizer based on soil test, usually a 1-2-3 NPK ratio is best, with a need for boron and other trace elements on lighter soils. Foliar fertilizers of liquid NPK on plants increases yield 62% with one application and 97% with two applications. Sunflowers should not occur in rotation more than once in every 4 years, and should not be in rotations with potatoes.

Harvesting

Crop matures about 4 months from sowing; some Russian cvs mature in 70 days. Harvest when involucral bracts turn yellow and seeds become loose, but before shedding begins. Harvesting methods are similar to those of corn: heads are gathered, dried, and threshed. For fodder or silage, crop is harvested at the flowering stage. Seed oil is either cold- or hot-pressed. Cold-pressed oil is usually pale yellow, with a mild taste and pleasant odor, much esteemed as a salad and cooking oil, especially for butter substitutes. Hot-pressed oil is reddish yellow and is used for technical purposes and as a burning oil. With modern methods, hot-pressed oil may be refined for edible purposes.

Yields and Economics

Average yields range from 900–1,575 kg/ha of seed; however, yields of over 3,375 kg/ha have been reported. Heads may contain 1,000–4,000 florets, with the potential of as many seeds. Yields from dried seeds are 40% oil, 35% protein meal, and 20–25% hulls. In 1979, the world low production yield was 308 kg/ha in Algeria, the international production yield was 1,266 kg/ha, and the world high production yield was 2,420 kg/ha in Austria (FAO, 1980a). With DM yields ranging from 4 to 9 MT/ha (in three months) and seed yields ranging from 300 to more than 3,000 kg/ha, a straw factor of 3 seems appropriate. According to USDA Secretary's Annual Report (1980), with an average yield of ca 1,500 kg/ha (North Dakota), a hectare would yield nearly 225 gallons of oil, 75% of which could be extracted on the farm. Twelve to 15 gallons are required to raise a hectare; hence the fuel from one hectare could produce 8–11 hectares of crop. In the US, the highest average commercial yields occurred in North Dakota and Minnesota, which averaged 1,170 and 1,267 kg/ha respectively, compared with 1,019 kg/ha for Texas. Pryde and Doty (1981) suggest average oil yields of 589 kg/ha from 1,469 kg/ha seed. Telek and Martin (1981) suggest oil yields of 450 kg/ha. Experimentally, at Davis, California, April plantings yielded 2,592–3,181 kg/ha (45.5–48.5% oil), May, 2,676–3,161 kg/ha (45.5–48.4% oil), June plantings 956–2,643 kg/ha (40.8–43.7% oil), and July plantings 702–2,447 kg/ha (40.2–42.6% oil). The lowest oil yield was 282 kg/ha, the highest, 1,543 kg/ha (Beard & Ingebretsen, 1980). In India, rainfed sunflower gave seed yields of 1,120 kg/ha in pure stands, 1,050–1,070 intercropped with cowpea, and 1,010–1,070 kg/ha intercropped with peanuts (Chandrasekar and Morachan, 1979). Volunteer sunflowers themselves may constitute a weed problem, as few as 3 per square meter reducing wheat yields by 16%, 23 per square meter reducing yields by 35% (Agrichemical Age, April 1982). World production of sunflowerseed in 1970 was 9.6 million MT, grown on 8.2 million ha, yielding 1,170 kg/ha. Largest producers are USSR, Rumania, Bulgaria, Argentina, Yugoslavia, Turkey, and South Africa. In the tropics, Tanzania produces 10,000–20,000 MT per year. Cultivars grown in Minnesota contain higher percentages of the desirable linoleic acid than same cultivars in other states. Major importers of sunflowerseed were Italy, West Germany, and Japan. Oil prices in United States in 1970 were $331/ton. Production costs in fully mechanized production in United States is about $100/ha with fertilizer, $87 without; hand labor figured at $2/hr. By 1982, sunflower oil was trading at $.59/kg compared to $.50–.54 for coconut, $.53 for cornoil, $.48 for cottonseed, $.59 for linseed, and $.42 for soybean (CMR, June 7, 1982).

Energy

According to the phytomass files (Duke, 1981b), annual productivity ranges from 3 to 15 MT/ha. North Dakota researchers are testing a small auger press, operated on the farm, that can extract ca 75–80% of the oil in sunflower seeds, or ca 55 gallons (barely more than one 42-gallon barrel) from an average yield of 1,400 lbs/acre. According to S&E Newsmakers #4 (September 1981), It takes one acre's production to farm and produce 8 to 11 more acres, our usual 10:1 ratio. In North Carolina, Harwood (1981) concluded that sunflower seed was most promising for on-farm production of vegetable oil fuels, soybeans, peanuts, and cottonseed considered not well suited. Sunflowers yield ca 2.5 MT/ha, with ca 40% oil, indicating a potential of 250 gallons oil/ha if seed were processed in mill. On farm processing would produce closer to 200 gallons (ca 5 barrels) at a cost of more than $2.00 per gallon. Production costs are less than one barrel per hectare. Harwood puts the energetic returns at greater than 5:1 compared to 3:1 for peanuts, 2:1 for soybeans, and 1:1 for cottonseed. Pratt et al. (VODF Seminar II, 1981) report an endurance test involving engines fueled with various mixtures of sunflower oil (25–50%) with diesel oil (75–50%). Two motors needed repair, ten were operating with no apparent difficulties, of which two were said to be doing even better. Ohio yields on poor soils (Wood County) were only 260 lb/acre (yielding 9.3 gallons of screw press oil); and on good soils (Champaign County), 1.680 lb/acre (yielding 69.1 gallons oil) cropped after wheat in a double cropping system (Ohio Report July–August 1981, p. 63). Sunflower oil should be dewaxed before being used as a diesel substitute. In Australia, sunflower first commercially planted in 1967, has great potential for expansion as a rainfed energy crop. Little water is required for processing oilseeds (unlike ethanol), and the seed coat can provide sufficient energy for heat and steam for oil extraction. Australians figure a net energy gain of 2 liters for every 3 liters produced (Quick, 1981). A hundred kg of dry seed will yield about 40 kg oil, 15–25 kg hulls, and 40 kg proteinaceous meal. Hulls have been pressed into fuel "logs". Threshed heads are ground and fed to cattle elsewhere. The heads are rich in pectin (Robinson, Ag. Ext. Service, Univ. of Minn.) Sheaffer et al. (1976, Univ. Md. Ag. Exp. Station) report studies showing that sunflower yields 33.1 MT silage/ha compared to corn at 19.26 MT/ha. According to the phytomass files (Duke 1981b), annual DM productivity ranges from 3 to 15 MT/ha. DM yields averaged closer to 5 MT spaced at 43,000 plants/ha, 8 MT spaced at 172,000 plants/ha near Clarksville, Maryland. In these experiments, the sunflower followed barley. Jake Page's discussion in Science 81 (July–August 1981, 92–93) is picturesque: "But I happen to like sunflowers... They can be grown almost anywhere in the country and you can grow between 500 and 3,000 pounds of sunflower seeds on an American acre in three months if you're clever. The soil can be lousy, the rainfall terrible...if the average American corn farmer put 10 percent of his land into sunflowers, he could become self-sufficient in fuel. It seems that using vegetable oil may be more efficient, in a net energy sense, than growing plants for conversion into alcohol (another nice alternative fuel) because the processing for alcohol is more elaborate, expensive, and energy intensive."

Biotic Factors

In USDA's Agriculture Research (Dec. 1978), a new pest of sunflower is reported. A scarab beetle (Phyllophaga lancolata) devastated more than 400 ha near Lehman, Texas. Eucosma womonana, is also a newly reported sunflower pest in Texas (Ag. Res., Aug. 1980). Seed set low when selfed, as most cultivars seed set low when selfed, as most cultivars are self-incompatible. Florets on one head open over 5–6 days and may wait 2 weeks for fertilization. Cross-pollination may be facilitated by 2–3 hives of honeybees per ha, the hives spaced in rows 300–400 m apart, as they need to be distributed to give coverage to all blooms. Gophers dig up seeds; birds eat tremendous amounts of seeds from the maturing crop. Insects can be destructive to seeds not stored properly. The following fungi are known to cause diseases in sunflowers: Albugo tragopogonis, Alternaria tenuis, Alternaria zinniae, Armillaria mellea, Ascochyta helianthi, Botrytis cinerea, Cercospora bidentis, Cercospora helianthi, Cercospora helianthicola, Cercospora pachypus, Corticium rolfsii, Cystopus cubicus, Cystopus tragopogonis, Diaporthe arctii, Diplodina helianthi, Entyloma polysporum, Erysiphe chicoracearum, Fusarium acuminatum, Fusarium conglutinans, Fusarium culmorum, Fusarium equiseti, Fusarium javanicum, Fusarium oxysporum, Fusarium sambucinum, Fusarium scirpi, Fusarium semitecum, Fusarium solani, Helminthosporium helianthi, Leptosphaeria helianthi, Leveillula compositarum, Leveillula taurica, Macrophomina phaseoli, Oidium helianthi, Ophiobolus helianthi, Phialea cynthoides, Phoma oleracea, Phymatotrichum omnivorum, Plasmopara halstedii, Puccinia helianthi, Pythium debaryanum, Pythium irregulare, Pythium splendens, Pythium ultimum, Rhabdospora helianthicola, Rhizoctonia rocorum, Rhizoctonia solani, Rhizoctonia bataticola, Rhizopus nodosus, Sclerotinia fuckeliana, Sclerotinia libertiana, Sclerotinia minor, Sclerotinia sclerotiorum, Sclerotium rolfsii, Septoria helianthi, Sphaerotheca fulginea, Sphaerotheca humuli, Uromyces junci, Verticillium albo-atrum, Verticillium dahliae. Bacteria reported as infecting sunflowers are the following: Agrobacterium tumefaciens, Bacterium melleum, Erwinia aroides, Pseudomonas cichorii, Pseudomonas helianthi, and Pseudomonas solanacearum. Virus diseases reported from sunflowers are: Apple mosaic, Argentine sunflower, Aster yellows, Brazilian tobacco streak, Cucumber mosaic, Tomato spotted wilt, Peach ringspot, Peach yellow-bud mosaic, Pelargonium leaf-curl, Tobacco necrosis, Tobacco ringspot, and Yellows. Sunflowers are parasitized by the following flowering plants: Cuscuta pentagona, Cuscuta arvensis, Orobanche aegyptiaca, Orobanche cumana, Orobanche muteli, Orobanche ramosa, Striga hermonthica, Striga asiatica, Striga lutea, Striga senegalensis. Sunflowers are attacked by many nematodes: Anguina balsamophila, Aphelenchoides ritzemabosi, Ditylenchus destructor, Ditylenchus dipsaci, Helicotylenchus cavenessi, Helicotylenchus microcephalus, Helicotylenchus microlobus, Helicotylenchus pesudorobustus, Heterodera schachtii, Longidorus maximus, Meloidogyne arenaria, Meloidogyne hapla, Meloidogyne incognita acrita, Meloidogyne javanica, Meloidogyne thamesi, Paratylenchus minutus, Pratylenchus penetrans, Rotylenchulus reniformis, Scutellonema clathricaudatum, Trichodorus christiei, and Xiphinema ifacolum.

References

Complete list of references for Duke, Handbook of Energy Crops
Last update Wednesday, January 7, 1998 by aw