The growth process of sunflower

The growth period of sunflower refers to the number of days from emergence to seed maturation, which is generally more than 85-120 days. The length of growth period varies with varieties, sowing dates and cultivation conditions. The whole growth period is divided into seedling stage, bud stage, flowering stage and mature stage. Let's take a look at the growth process of sunflower.

Seedling stage

Sunflower from emergence to budding is called seedling stage, which usually takes 35-50 days and summer sowing 28-35 days. This period is the stage of leaf, flower primordium formation and floret differentiation. Sunflower seedling stage is the strongest stage of drought resistance, the aboveground growth is slow, the underground root grows faster, and quickly forms a strong root system.

Budding stage

The appearance of a star with a diameter of 1 cm at the top of the sunflower is commonly known as budding, which takes about 20 days from budding to flowering, which is the most exuberant period of vegetative growth and reproductive growth. During this period, sunflowers need the most fertilizer and water, accounting for about 4050% of the total amount of fertilizer needed. If the need for water and fertilizer can not be met in time, the yield will be seriously affected.

Flowering stage

In the sunflower field, 75% of the ligulate flowers enter the flowering stage, and it usually takes 6-9 days for a disk to open from the ligulate flower to the tubular flower, and the inflorescence is in full bloom from the second day to the fifth day. The number of flowers in these four days accounted for about 75% of the number of flowers. Most of the flowers bloom at 4: 00 to 6: 00 in the morning and pollinate the next morning. The unpollinated branches can remain unwithered for 7 to 10 days. The seed setting rate of self-pollination of sunflower is very low, only about 3%, and the seed setting rate of cross-pollination is high. However, if the temperature is high, Rain Water is more, the humidity is high, the light is insufficient, and the soil is dry, the seed setting rate will be greatly reduced. Therefore, adjusting sowing date, timely fertilization and watering, prevention and control of diseases and insect pests, and taking measures such as bee release or artificial pollination can improve the seed setting rate.

Mature stage

The mature period of sunflower refers to the stage from flowering to maturity, with 25-55 days of spring sowing and 25-40 days of summer sowing. About 15 days after flowering and pollination shield is the stage of grain formation. Sunflower maturity needs sunny weather, large diurnal liquid temperature difference and suitable soil moisture.