Stevia rebaudiana is a perennial herb of Stevia in Compositae. The Amanbai Mountains, which originated from the border between Paraguay and Brazil in South America, is a valuable sugar crop. The whole plant contains sugar, and the leaves are the sweetest. The glycoside content is 14%, and the glycoside content of branches is half that of leaves. The leaves can be used as sugar after drying and crushing, or treated with hot alcohol, and 20-26% egg-yellow crude extract can be obtained by ether precipitation. The sweetness is 100- 150 times that of white sugar, the refined product is white, the sweetness is 250-300 times that of white sugar, and the heat is only 1/300 times that of white sugar. Stevioside has been widely used in food industry to replace saccharin. As a waterlogging agent, it is added to sauces such as soy sauce and pickled melon, which has antiseptic effect. As a tonic, anti-hangover agent and stomach tonic, it has the functions of raising blood sugar and promoting human metabolism.

The plant height is generally 70-80cm, the old stem is semi-lignified, the stem diameter is about 1cm, it is highly branched, and there is no obvious main stem. The leaves are lanceolate, and there are milky white short hairs on both sides of the leaves and on the stems and branches. Achene fruit, spindle-shaped seeds, 2-3mm long, mature seeds black or dark brown, 1000-grain weight 0. 18-0.35g, chromosome number 2n=22.

Sex likes temperature and humidity, and is not strict with soil. It grows well when the soil is moist, the fertilizer is sufficient, and the temperature is above 15℃, and it is resistant to high humidity and drought. Applying compost and lime can increase the yield. Plants cultivated in the first year have large crowns, so they should be planted closely to prevent lodging. In the second year, the plant type changed, and many stems were born on the ground, with fewer small branches. Generally, new roots are added every year, and the old roots of the previous year gradually lose their functions and finally disappear and die. In the fourth year, the root system is so large that the roots on it cross each other, so that the plant growth begins to decline.

Stevia rebaudiana was originally a wild cross-pollinated plant. After years of introduction and domestication, its offspring have been widely separated and varied greatly. The mixed strains include big leaves, small leaves, thick leaves, thin leaves, late maturity, early maturity, disease resistance, no disease resistance, drought resistance and no drought resistance. It can be propagated by seeds or cuttings, and the survival rate of cuttings is high at 20℃. Seeds germinate best in the dark. Cuttings with tender shoots and shoots are preferred, and cuttings in the middle of branches can also be selected. Cutting seedling can be combined with field transplanting and topping, and seedlings can be inserted with harvest to prevent wilting. The humidity of the seedbed should be high. No matter whether growing points or twigs are used, at least three or four leaves should be removed, and two-thirds of other leaves should be removed, and then inserted into wet soil or wet sand. Six pairs of leaves can be transplanted with soil, and the row spacing is 50× 10cm. Generally, it will turn green after transplanting 10. After survival, loosen the soil, and combine with soil cultivation and fertilization before sealing the soil to prevent lodging. Apply nitrogen fertilizer frequently and less topdressing, and stop using nitrogen fertilizer before harvest 10 day to avoid water accumulation and prevent root rot.

These diseases include Rhizoctonia solani. Leaf spot, white silk disease, etc. , mostly in high temperature and high humidity season. The main pests are earthworm, mole cricket, cutworm, cabbage caterpillar, aphid and so on.

The suitable harvesting period is from the initial flowering stage to the full flowering stage. Generally, the leaves are harvested for 2-3 times, and the yield of dry leaves per hectare is 750-2250 kg; ; Generally, harvesting begins about 80 days after planting, and then the stems and branches above the ground 15cm are harvested every other month, leaving 6- 10cm at the base branches to maintain photosynthesis. Top dressing in time after each leaf is harvested. The harvested leaves should be dried in time or at about 50℃, and the water content should not exceed 65438 00%.