Gannan Rice

Gannan Rice

　　Belonging to the Poaceae family, it has a fibrous root system with well-developed adventitious roots. The inflorescence is a panicle and the plant is self-pollinating. It is an annual cultivated cereal crop. The stems are erect, growing 30–100 cm tall. The leaves are arranged alternately in two rows, linear-lanceolate in shape, with membranous, bilobed ligules. The panicle is loose; the spikelets are oblong, laterally compressed, and contain three florets. The glumes are highly reduced, leaving only traces, while the uppermost floret is bisexual with a boat-shaped lemma and an awn; there are six stamens. Two reduced florets retain only their lemmas, located beneath the bisexual floret, often mistaken for glumes. The fruit is a caryopsis. Originally from tropical Asia, it is one of the world's major staple crops.

In China, rice cultivation accounts for one-quarter of the total grain crop area but yields more than half of the total grain production. With a cultivation history of 6,000–7,000 years, it is an important food crop. In addition to being consumed as caryopses, rice can be processed into starch, used for brewing alcohol, and making vinegar. Rice bran is used for making sugar, extracting oil, and producing furfural for industrial and medicinal purposes. Rice straw serves as excellent fodder, raw material for papermaking, and weaving. Rice sprouts and roots have medicinal uses.

Rice is an annual plant of the Poaceae family, growing to about 1.2 meters in height, with long, flat leaves. Its inflorescence is a panicle composed of many spikelets. The edible grains are called paddy, which become rice or milled rice after dehulling. Nearly half of the world’s population, including almost all people in East and Southeast Asia, rely on rice as a staple food. The cultivation of rice dates back to around 3000 BCE in India and gradually spread westward, reaching southern Europe in the Middle Ages. Except for upland rice varieties, rice is typically grown in flooded areas such as coastal plains, tidal deltas, and river basins in tropical, subtropical, and temperate regions. Seeds are sown in prepared seedbeds and transplanted to flooded paddies with surrounding embankments, at a water depth of 5–10 cm, when the seedlings are 20 to 25 days old. The fields remain submerged throughout the growing season. The harvested grains are called paddy, enclosed in a hull, which along with the bran layer is usually removed during milling. Sometimes a thin coating of glucose and talcum powder is added to give the grains a glossy finish. Rice that is milled only to remove the hull is called brown rice, rich in starch and containing about 8% protein and small amounts of fat, as well as vitamins such as thiamine, niacin, riboflavin, iron, and calcium. Rice from which both the hull and bran have been removed is called white rice or polished rice, and its nutritional value is significantly lower. Rice is commonly eaten as cooked plain rice. In East Asia, the Middle East, and many other regions, it is also served with various soups, side dishes, and main teas. By-products of rice milling include rice bran, finely ground rice bran powder, and starch extracted from rice bran, all of which are used as animal feed. Oil extracted from rice bran can be used for both food and industrial purposes. Broken rice is used for brewing, alcohol extraction, and the production of starch and rice noodles. Rice husks can serve as fuel, filler, polish, or be used to make fertilizer and furfural. Rice straw is used for fodder, livestock bedding, roofing material, packaging, and can also be made into mats, clothing, and brooms. Major rice-producing countries include China, India, Japan, Bangladesh, Indonesia, Thailand, and Myanmar. Other significant producers are Vietnam, Brazil, South Korea, the Philippines, and the United States. In the late 20th century, global annual rice production averaged around 400 billion kilograms, with a cultivation area of approximately 145 million hectares. About 95% of the world’s rice production is consumed by humans.

Rice thrives in high temperatures, high humidity, and short daylight conditions. It is not demanding on soil types, though paddy soil is most suitable. The minimum germination temperature for seedlings is 10–12°C, with the optimum at 28–32°C. Tillering requires a daily average temperature above 20°C, and the ideal temperature for panicle differentiation is around 30°C; low temperatures prolong the differentiation of branches and spikelets. The optimal temperature for heading is 25–35°C. Flowering performs best at around 30°C, while temperatures below 20°C or above 40°C severely affect fertilization. A relative humidity of 50–90% is ideal. The period from panicle differentiation to the peak of grain filling is critical for yield formation; balanced nutrition and a high photosynthetic efficiency in the plant canopy are essential for improving grain setting rate and weight. The heading and grain-filling stages require ample water and mineral nutrients; it is also vital to maintain root vitality and extend the functional period of stems and leaves. Approximately 500–800 kg of water is needed to produce 1 kg of rice.