pronounced: gly-SEE-nee maks
Glycine is derived from the Greek γλυκυς (glykys), sweet, referring to the sweet roots and leaves of some species; max is from the Latin maximus, largest.
Soya beans are one of the world’s most important sources of both oil and protein. In various parts of the world you will find the unripe seeds eaten as a vegetable, and the dried seeds eaten whole, or split, or sprouted; the processed seeds give soy milk; the mature seeds, fermented, give soy sauce; the roasted seeds are used as a coffee substitute; the oil is used in the manufacture of such products as paint and linoleum, printing inks and disinfectants; soy meal is used as a livestock feed; soy flour (from the whole beans) is increasingly being used as an additive to cereal flour, and in health foods: the list is almost endless.
The plant is a bushy annual herb. The stems can grow up to about 160 cm in height, terete towards the base, and very hirsute with pale hairs. The leaves are pinnately trifoliate, with petioles 2 – 20 cm long; the leaflets are membranous, usually elliptic-lanceolate in shape, although this varies with the cultivar.
The flowers are in axillary racemes that are irregular, often leafy, very short (1 – 3.5 cm long), usually 5 – 8-flowered, the peduncle and pedicels often reduced and densely hirsute. The inconspicuous, self-fertile flowers are white, pink or purple.
The pods are also hirsute, and grow in clusters of 3 – 5; each pod is 3 – 8 cm long, and usually contains 2 – 4 seeds, each seed generally less than 1 cm in diameter.
The cultigen species was domesticated in north-eastern China some time before 1000 BC from Glycine soja. From the 1700s Europeans visiting the far east began bringing soya bean seed to Europe, and introducing it into their colonies. It was being grown in the USA from the late 1700s, but its cultivation there did not really take off until World War II, with the need for butter substitutes. It was also adopted by maize farmers as part of their crop rotation, for its nitrogen-fixing ability.
The self-pollinating ability of the species means that it is easy to keep separate breeding lines, and this has resulted in an enormous number of cultivars, often differing in seed colour. One of the aims of plant breeders has been to improve digestibility, as this is one of the drawbacks of many soy products.
The plant is subject to attack by the caterpillars of many species of Lepidoptera, including:
• the Beet Webworm Spoladea recurvalis;
• the Soybean Looper Thysanoplusia orichalcea;
• the Castor Caterpillar Achaea janata;
• the Beet Armyworm Spodoptera exigua;
• the Black Cutworm Agrotis ipsilon;
• the Hairy Caterpillar Creatonotos gangis;
• the Bean Looper Mocis alterna;
• the Soybean Moth Aproaerema simplexella;
• the Lima Bean Pod Borer Etiella zinckenella; and
• the Tomato Looper Chrysodeixis acuta.
