SAINFOIN
Onobrychis viciifolia Scop, family LeguminosaeSainfoin is sometimes called esparcet or holy clover. The crop is limited to a few acres grown in Montana.
Plant:
Sainfoin is a perennial with a deep taproot and stout erect stems arising from a many-branched crown. Some plantings in Montana are 60 years old and still used for pasture (Dubbs 1967). The plant may grow from 15 to 40 inches high. It requires a soil rich in lime. Because it can withstand temperatures as low as -40 deg F., it can grow in the coldest parts of the country.
Inflorescence:
The pinkish or rose-colored flowers occur on terminal, erect, close racemes at the top of the plant, giving a field in flower a delicate rose color. The flower mechanism is essentially like that of white clover or sweetclover. The weight of a bee on the flower causes the stigma and anthers to protrude from the keel, then return after the weight is removed. The stigma projects beyond the anthers so that cross-pollination is assured should the bee visit occur. Lateral access to the nectar in the flower by the bee is impossible. The calyx tube is only 2 to 3 mm deep, so most melliferous insects can reach the nectar and pollen. The style becomes more and more erect as anthesis progresses, and ultimately projects 1 to 1 1/2 mm beyond the cleft in the keel (Knuth 1908*, p. 319). Tereshchenko (1949) stated that flowers may open throughout the day but mostly in the morning. They usually remain open only 1 day. Flowering begins at the base of the raceme and takes 2 to 3 weeks to reach the tip. The seed develops in a one-seeded pod.
Sainfoin blossoms secrete nectar excessively and are highly attractive to pollinating insects, particularly honey bees. Pollen is also produced in abundance. Dubbs (1968) stated that 20 hives placed on 4.78 acres was insufficient for bee saturation. An estimated ninetenths of all bee visitors were honey bees.
Graham (1941*), Madoc (1934), Alfonsus (1929), Dubbs (1967), and Pellett (1947*) reported that sainfoin honey is of the finest quality. Kropacova (1969) calculated the total quantity of nectar sugar produced as 32.8 to 130.3 kg/ha or 29 to 155 lb/acre.
Pollination Requirements:
Bosca and Hejja (1963) stated that self-fertility of the plants ranged from zero to 37 percent. They also found that inbred plants produced only 70 percent as many stems and weighed only 73 percent as much as crossed plants. Knuth (1908*, pp. 318-319) indicated that cross- pollination of sainfoin flowers was required because automatic self- pollination does not occur. Kropacova (1969) found that seed production of exposed plants was 10 to 25 times as great as that from plants caged to exclude bee visitors (caged plants yielded 9.75 g/m2), whereas plants exposed to bees yielded 179.13 g/m2). Sainfoin seed production is primarily dependent upon bee pollination. The most effective time for bees to visit sainfoin flowers has not been determined, nor has the effect of bee pollination on the appearance of the flower. Flowers of many other species of plants begin to fade or wilt shortly after they are pollinated.
Tereshchenko (1949) caged plants to exclude bees and obtained only 3.2 percent set of blooms (3.2 g seed) compared to 42.7 percent set (49.2 g seed) of those not caged. He also found a high negative correlation between distance from the apiary and seed set.
Pollinators:
The honey bee is doubtless the most populous of insect visitors to sainfoin flowers. Pellett (1947*) stated that he saw 100 bees on sainfoin for each 10 on white clover, a plant considered highly attractive to bees. Honey bees begin visiting the flowers quite early in the morning and continue to visit them throughout the entire day.
Pollination Recommendations and Practices:
Kropacova (1969) recommended two to three colonies of honey bees per hectare (about one colony per acre) located close to the field. This seems rather low when we consider Dubbs' (1968) statement that 20 colonies placed on a 4.78-acre seed field were insufficient for bee saturation. He calculated that two to three colonies per acre would provide five or six visits to every sainfoin flower. This would appear to be low, thus more colonies may be required.
LITERATURE CITED:
ALFONSUS, J.
1929 SAINFOIN NEXT TO THE CLOVERS AS A HONEY PLANT. Amer. Bee Jour. 79: 113-115.BOSCA, I., and HEJJA, S.
1963. [DATA ON FERTILIZATION IN SAINFOIN (ONOBRYCHIS VICIIFOLIA SCOP.).] Novenytermeles 12(2): 137-142. [In Hungarian, English summary.]DUBBS, A. L.
1967. SAINFOIN: A NEW HONEY CROP FOR MONTANA. Amer. Bee Jour. 107: 18-19.______ 1968. SAINFOIN AS A HONEY CROP. Mont. Agr. Expt. Sta. Bul. 627: 108-109.
KROPACOVA, S.
1969. THE RELATIONSHIP OF THE HONEY BEE TO SAINFOIN (ONOBRYCHIS SATIVA). In 22d Internatl. Apic. Cong. Proc., Munich, pp. 476-477.MADOC, E. W. D.
1934. SAINFOIN, FODDER AND HONEY PLANT. Amer. Bee Jour. 74: 201.TERESHCHENKO, A. K.
1949. [POLLINATION OF SAINFOIN BY HONEYBEES ] Pchelovodstvo 26(6): 338 - 341. [In Russian.]
