BUCKWHEAT 19
Fagopyrum esculentum Moench, family PolygonaceaeBuckwheat, once a highly important crop in the United States, appears to be in the twilight of its day. In 1918, more than a million acres were grown (Quisenberry and Taylor 1939). Over half of that acreage was in Pennsylvania and New York. Twenty years later the total acreage was less than one-half million. By 1954, only 150,000 acres were harvested, and in 1964 when USDA crop production records for buckwheat were discontinued, only 50,000 acres were harvested. Seed production ranged from 500 to 1,700 lb/acre, depending on various cultural factors, not the least of which was completeness of bee pollination (Carmany 1926, Kopel'skievsky l960, Martin and Leonard 1949*). However, Root (1891) reported a phenomenal yield of 3,840 lb/acre in one instance. The limited acreage of buckwheat in the United States is in the Great Lakes region and eastward. In 1970, Russia led all other countries in buckwheat production with more than 4.5 million acres (United Nations Food and Agriculture Organization (FAO) 1971, p. 80). Buckwheat is grown primarily for the seeds, which are ground into flour and used in buckwheat cakes.
__________
19 Tartary buckwheat, Fagopyrun tarticum (L.) Gaertn., is a more slender plant than F. esculentum, with smaller greenish or yellowish flowers and not as aggregated. According to Naghski (1951), extensive plantings of tartary buckwheat have been made in recent years because it is a good source of rutin, a drug used to reuce capillary blood pressure and relieve atomic radiation injury. This species is seldom visited by bees and is self-fertile ( Garber and Quisenberry 1927).Plant:
Buckwheat is an annual, 2 to 4 feet tall, with a single stem and several branches bearing heart-shaped leaves (fig. 55). The green to red stem turns brown with age. More reddening is evident with poor seed set. The l/5-inch flowers are in clusters mostly at or near the top of the plant (fig. 56). Flowering is indeterminate, and the plants which are usually broadcast are often harvested with some immature seeds and even flowers present. A field in flower is chalky white and has a pronounced aroma that some people consider unpleasant. Flowering in a field may begin 5 to 6 weeks after planting and may continue for 25 to 30 days (fig. 57).
[gfx] FIGURE 55. - buckwheat plant in bloom.
FIGURE 56. - buckwheat flowering branch.
FIGURE 57. - field of buckwheat in full bloom.Inflorescence:
The buckwheat flower has no petals - the sexual parts, the ovary, three styles and eight stamens being enclosed in the petallike sepals. Four of the anthers bend out but turn their pollen inward. The other four turn their pollen outward (Knuth 1909*, pp. 341 - 342). Some plants have flowers, referred to as the "thrum" type, with short styles and long filaments so the stamens extend above the styles. Other flowers, referred to as "pin" types, have long styles and short filaments so the stigma is above the anthers. Occasionally, the styles and stamens are at the same height. The long stamens and filaments are fully 3 mm; the shorter ones, about 2 mm. Although each plant bears flowers of only one form, the seeds from either form will produce plants having the dimorphic forms in about equal numbers. The three styles lead to a single ovary with one ovule, so a flower can produce only one seed, which is about one-quarter inch long.
The flower, which opens in the morning around 8 a.m., has eight yellow nectaries alternating with the eight filaments at the base of the ovary, bound together by a cushionlike swelling (Knuth 1909*, pp. 341 - 342). The flower (fig. 56) secretes nectar in copious amounts, but only in the morning hours, during which time it is highly attractive to bees (Phillips and Demuth 1922). Toward noon, the flow lessens, and during the afternoon honey bees usually abandon the plants. Pollen is also collected by honey bees from buckwheat.
A colony of honey bees having access to a field of flowering buckwheat may store 10 to 15 pounds of honey per day (Versehora 1962), and collect 90 to 290 pounds of nectar per acre (Free 1970* Martin and Leonard 1949*). The honey produced by buckwheat is dark with a strong flavor that is usually relished only by people who are accustomed to it; however, there is a greater demand for this honey than can be supplied. The honey is used primarily in the baking of foods. During a buckwheat nectar flow, the apiary may have a strong sometimes nauseating aroma which can be detected for some distance (Pellett 1947*). Mel'nichenko (1963) thought that removal of nectar by bees stimulated greater secretion. He stated that secretion ceases after the flower has been fertilized.
Bukhareva (1964) and Leshchev (1962) reported that some trace elements caused an increase in buckwheat nectar secretion and seed yields. This was supported by, Kopel'skievsky (195S, 1960), Leshchev (1962), anc Skrebtsova (1957) who found that the fertilizers calcium, nitrogen, and phosphorus increased the pollination effectiveness of honey bees. Demianowicz and Ruszkowska (1959) found that all the cultivars tested were important sources of pollen, but some were much better sources of nectar than others. With many nectar-producing plants decreasing or disappearing from a beekeeper's area he might encourage buckwheat planting nearby to supplement his bee forage.
Pollination Requirements:
The buckwheat flower is usually unable to self-pollinate. The flower type prevents the pollen from automatically coming in contact with the stigma. Exceptions include the occasional flowers with pistil and stamens of the same length, which usually have a low degree of self-fertility. A recent selection (F. sagittatum Gilib.) has been developed which has stamens and pistil at the same level, with a high degree of self-fertility, but of no direct commercial value (Marshall 1970). Buckwheat pollen is not windblown, therefore insects are necessary for the transfer of the pollen. Davydova (1954) found that, as is customary for dimorphic flowers, the pollen grains on the two types of stamens are different in size, the flowers with longer stamens having larger grains (46 to 67 by 39 to 55 microns, versus 35 to 44 by 29 to 40 microns for grains on the shorter stamens). The analyses by Davydova (1954) of pellets of pollen taken from honey bees working buckwheat, showing that both types of pollen were present, was confirmed by Roz[s]ov and Sc[k]rebtsova (1958). This proved that the bees move freely from one type of flower to another and are thus effective pollinating agents of this crop.
The necessity of insect pollination for commercial seed production of buckwheat has been well established by Garber and Quizenberry (1927) in the United States and numerous workers in Russia, where this crop is grown so extensively (Elagin 1953, Glukhov 1955, Kashkovskii 1958, Mel'nichenko 1962, and Sevcuk 1946). Free (1970*), after reviewing the pollination of buckwheat, pointed out the need for some controlled cage tests on this crop to determine the degree of self-pollination if any occurred and the quantity of seed that might be expected under different pollination conditions.
Pollinators:
Unquestionably, the honey bee is the best pollinator of buckwheat because it is highly attracted to the buckwheat flower and efficiently and effectively transfers the pollen from anthers to stigmas, whether collecting pollen or nectar.
Leighty (1919) stated that many buckwheat growers believed that the weight per bushel of seed was heavier where the crop had been worked heavily by bees. Elagin (1953) showed the following correlation between the 2-year average yield of buckwheat seeds and distance in meters from the apiary. Distance from apiary
Distance from apiary in meters Yield of buckwheat seed in meters in kilograms per hectare ÒNearÓ 850 500 770 1,000 720 1,500 575
The number of colonies in relation to the area of buckwheat was not given by Elagin (1953), although where five colonies per hectare were present, 80.4 percent of the seeds set, but with only one colony per hectare, the set was only 57.8 percent. The transportation of colonies to the buckwheat fields was encouraged because of their value as pollinators.
Glukhov (1955) obtained 1,700 kg buckwheat seed per hectare within 500 m of the apiary, but production dropped to 1,200 kg in the 500- to 1,000-m range, and only 500 kg/ha at 2,000 to 3,000 m from the apiary. In another field, he obtained 2,500 kg/ha of seed adjacent to the apiary, 1,900 kg at 500 m and 1,300 kg/ha 1,000 m from the apiary. Similarly, Kopel'skievsky (1960) obtained 1,470 kg/ha seed adjacent to an apiary, but only 840 kg/ha 2,000 m away.
Pollination Recommendations and Practices:
There are no recommendations in this country in relation to bee populations and buckwheat seed production. In Canada, one colony per acre is recommended (Smith et al. 1971). In Russia, Kashkovskii (1958) stated that there should be enough bees for each flower to receive five or six visits. Mel'nichenko (1962) stated that about two colonies per acre were needed for saturation pollination and highest buckwheat yields; however, when he used about three colonies per acre, he obtained 1,250 to 1,500 lb per acre. Doubtless, the colonies per acre necessary to supply the five to six visits per flower varies with location and conditions.
LITERATURE CITED:
BUKHAREVA, G. A.
1964. [EFFECT OF TRACE ELEMENTS USED IN PRE-SOWING TREATMENT, AND OF FOLIAR FERTILIZERS, ON NECTAR SECRETION IN SOME AGRICULTURAL CROPS.] Trud. Nauch-Issled. Inst. Pchelovodstvo 140-194. [In Russian, English summary.] AA-769/65.CARMANY, C. E.
1926. BUCKWHEAT IN MICHIGAN. Mich. Agr. Expt. Sta. Spec. Bul. 151, 11 pp.DAVYDOVA. N. S.
1954. [ANALYSIS OF HONEY BEE POLLEN LOADS FROM BUCKWHEAT.] Uchen. Zap. Kishinev Gos. Univ. 13: 167-173. [In Russian.] AA-104/64.DEMIANOWICZ, Z., and RUSZKOWSKA, B.
1959. [THE NECTAR FLOW FROM BUCKWHEAT.] Pszczel. Zesz. Nauk. 3(1): 11 - 24. [In Polish.] AA-342/64.ELAGIN, I.
1953. [INFLUENCE OF POLLINATION BY BEES ON THE YIELD FROM BUCKWHEAT.] Pchelovodstvo 6: 31-33. [In Russian.] AA-117/54.GARBER, R. J., and QUISENBERRY, K. S.
1927. SELF-FERTILIZATION IN BUCKWHEAT. Jour. Agr. Res. 34: 185 - 190.GLUKHOV, M. M.
1955. [HONEY PLANTS.] 512 pp. lzd. 6, Perer. i Dop. Moskva, Gos. Izd-vo Selkhoz Lit-ry. [In Russian.]KASHKOVSKII
1958. [ECONOMIC RESULTS OF POLLINATING BUCKWHEAT CROPS BY HONEYBEES AND BY HAND.] Byull. Nauch-Tekh. Inf., Kemerovo 2-59-61. [In Russian.] AA-390/60.KOPEL'KIEVSKY, G. V.
1955. [POLLINATION OF BUCKWHEAT BY BEES.] Pchelovodstvo 32: 41 - 48. [In Russian.] AA-55/57.______ 1960. [BEES AND BUCKWHEAT SEED CROP.] Pchelovodstvo 37(4): 36 - 39. [ In Russian.] AA-683/63.
LEIGHTY, C. E.
1919. BUCKWHEAT. U.S. Dept. Agr. Farmers' Bul. 1062, 24 pp.LESHCHEV, V.
1952. [MODERN AGRICULTURE INCREASES NECTAR PRODUCTION OF BUCKWHEAT.] Pchelovodstvo 29: 23 - 26. [In Russian.] AA-54l57.MARSHALL, H. G.
1970. REGISTRATION OF ÔPENNLINE 10Õ BUCKWHEAT. Crop Sci. 10: 726.MEL'NICHENKO, A. N.
1962. [BIOLOGICAL BASIS FOR INCREASING THE YIELD OF BUCKWHEAT BY DIFFERENT SOWING DATES AND DEGREES OF SATURATION OF BEE POLLINATION. ] Uchen. Zap. Gor'kov. Univ. 55: 5-43. [In Russian.] AA-667/64.MEL'NICHENKO. A. N.
1963. [BEES THEMSELVES INCREASE THE NECTAR PRODUCTIVITY OF FLOWERS.] Pchelovodstvo 49(9): 32 - 35. [In Russian. ] AA-566/65.NAGHSKI, J.
1951. NO HONEY FROM TARTARY BUCKWHEAT. Amer. Bee Jour. 91: 513.PHILLIPS, E. F., and DEMUTH, G. S.
1922. BEEKEEPING IN THE BUCKWHEAT REGION. U.S. Dept. Agr. Farmers' Bul. 1216, 26 pp.QUISENBERRY. K. S., and TAYLOR. J. W.
1939. GROWING BUCKWHEAT. U.S. Dept. Agr. Farmers' Bul. 1835, 17 pp.ROOT, A. I.
1891. THE ABC OF BEE CULTURE. 408 pp. A. I. Root Co., Medina, Ohio.SEVCUK, I.
1946. [PROSPECTS FOR THE DEVELOPMENT OF APICULTURE IN THE UKRAINE.] Soc. Seljs. Hoz. 12: 32-37. Herbage Abs. 18(3): No. 695.SKREBTSOVA, N. D.
1957. [POLLINATION OF BUCKWHEAT FLOWERS BY BEES.] Pchelovodstvo 34(9): 48 - 50. [In Russian.] AA-135/59.SMITH, H., PANKIW, P., KREUTZER, G., and others.
1971. HONEY BEE POLLINATION IN MANITOBA. Manitoba Dept. Agr. Pub. 525, 16 pp.UNITED NATIONS FOOD AND AGRICULTURE ORGANIZATION (FAO)
1971. 1971 yearbook. V. 25, 829 pp.VERSEHORA, D.
1962. [BUCKWHEAT AND ITS IMPORTANCE FOR APICULTURE.] Apicultura 15(6): 11-14. Bucharest. [In Romanian.] AA-765/65.
