Sesamum indicum L. family Pedaliaceae
Sesame, sometimes known as benne, is grown for its edible oil pressed from the seed and for the decorticated (hulled) edible seed (Martin and Leonard 1949*).
World production in 1968 was estimated at 640,000 tons of sesame oil. This would indicate that about 10 million acres were devoted worldwide to this crop. In 1955, about 15,000 acres were grown in the United States, mostly in Texas and New Mexico.38 In the United States, sesame is grown in the Southwestern, Southern, and South Central States. Although there was essentially no production in 1971, there is considerable interest in reviving production. Tests have shown that under extremely favorable conditions as much as 2,000 pounds of seed per acre can be produced. Nonshattering cultivars were developed in 1953 (Kinman 1955).
38 KINMAN, M. L. SESAME PRODUCTION. U. S. Dept. Agr., Agr. Res. Ser., Tex. Agr. Expt. Sta. 1956. [Mimeographed.]
Sesame is an annual erect herb, 3 to 5 feet tall, which is grown in rows 18 to 42 inches apart with 6 to 10 plants per foot of row (USDA 1958). The 3- to 5-inch-long leaves are opposite, oblong, and, in the older cultivars, smooth and flat. In the nonshattering cultivars the leaves are cupped and have small leaflike outgrowths on their underside. Some cultivars have many branches, whereas others are relatively unbranched. Thousands of cultivars are known, with lifespans ranging from 2 to 6 months. Sesame is killed by frost; however, seed harvest before frost is preferred. Because large-scale cultivation equipment can be used, growers can handle large acreages. A single plant is capable of producing several thousand seeds (Kinman and Martin 1954).
The tubular, pendulant, bell-shaped, two-lipped flower is pale rose to white and 3/4 to 1 inch long. The two lobes of the upper lip are shorter than the three lobes of the lower (Bailey 1949*). One flower is produced at the axil of each leaf. The lower flowers usually begin blooming 2 to 3 months after seeding, and blooming continues for some time until the uppermost flowers are open.
Sesame is a source of nectar and some honey for beekeepers primarily because it flowers in midsummer when little else in the area is blooming. It is an excellent source of pollen for bees. It also attracts various other bees and other insects that feed on its pollen or nectar; however, honey bees are the primary visitors (Langham 1944).
Sesame is usually considered to be a self-pollinated crop (Kinman and Martin 1954) although the amount of cross-pollination that occurs is considerable. Van Rheenen (1968) recorded 5.5 to 9.6 percent crossing but gave no indication as to what pollinators might be responsible. Langham (1944) obtained an average of 4.6 percent (0.50 to 9.58 percent) outcrossing, which he attributed to honey bees. Martinez and Quilantan (1964) observed 0.15 to 9.39 percent crossing, with higher crossing observed during winter when the bee population was higher. Langham (1944) covered plants to exclude insects and obtained relatively as much seed set as on plants exposed to bee visitation. However, Srivastava and Singh (1968) obtained yield increases of 43.66 percent over the best parent when they crossed Meghna with local cultivars and 38.0 percent when they crossed Meghna with wild plants. This indicated that hybrids might be produced that would outyield current cultivars. A crossing method involving bees might prove quite beneficial.
Honey bees are the primary visitors to sesame flowers. Langham (1944) stated that the bee alights on the protruding lip of the flower and squeezes inside. Later, it emerges coated with pollen and flies to another flower. However, no benefit from such crossing, although established in many other crops that have been considered self-pollinating, has been established for sesame. The high percentage of heterosis shown by Srivastava and Singh (1968) strongly indicates that insect pollination would be beneficial in the production of superior hybrid seed.
The effect of insect visitation on the individual flower has not been studied.
Pollination Recommendations and Practices:
KINMAN, M. L.
1955. SESAME. Econ. Bot.9(2): 150.
______and MARTIN, J. A
1954. PRESENT STATUS OF SESAME BREEDING IN THE UNITED STATES. Agron. Jour. 46(1): 24-27.
LANGHAM D. G.
1941. NATURAL AND CONTROLLED POLLINATION IN SESAME. Jour. Hered. 35(8): 254-256.
MARTINEZ, H. G., and QUILANTAN, V. L.
1964. [PERCENT OF NATURAL CROSS-FERTILIZATION OF SESAME IN IGUALA, GROS.] Agr. Tecnologia Mex. 11(4): 175-177. [In Spanish.]
RHEENEN, H. A. VAN.
1968. NATURAL CROSS-FERTILIZATION IN SESAME (SESAMUM INDICUM L.). Trop. Agr. [Trinidad] 45(2): 147-153.
SRIVASTAVA D. P., and SINGH, S. N.
1968. HETEROSIS IN SESAME. Indian Bot. Soc. Jour. 47(1/2): 79-88.
UNITED STATES DEPARTMENT OF AGRICULTURE.
1958. SESAME PRODUCTION. U.S. Dept. Agr. Farmers' Bul. 2119,12 pp.