How to select sunflower seeds in field

Sunflower is a cross-pollinated crop, which has been planted in many places in recent years, and little attention has been paid to field seed selection in some places, resulting in mixed degradation of varieties, poor quality, declining oil content and other problems, which have a great impact on the yield and quality of sunflower seeds. At present, sunflower is about to mature, so it is very necessary to do a good job in sunflower field selection. According to various experiences, it is a simple and effective way to select seeds in the field before sunflower harvest. According to the experimental investigation, the yield of the seeds selected in the field is 20% more than that of the unselected seeds, and the progress of growth and development is uniform, which creates favorable conditions for timely harvest. First, four links should be grasped in field seed selection. 1. To determine the excellent varieties suitable for local planting, select plants with the particularity of this variety. 2. Select disease-free living plants and plants without branches, large disk, full seeds and medium height. 3. Choose a convex and slightly convex disk with an angle of 45-70 degrees with the stem. Because the small inclination of the disk is not good, but also vulnerable to birds and germs, when the seed mature disk buried in the canopy, easy to mildew, inconvenient to harvest. 4. After the disk is removed, it should be transported, dried, threshed and stored separately. Second, select excellent varieties. Sunflower can be divided into oil sunflower and food sunflower, oil sunflower plant is shorter, seed is small, mainly used for oil extraction; sunflower plant is tall, grain is large, generally used for eating or as a food additive. Oil sunflower had better choose hybrids with high yield and high oil, such as "Baikuiza No. 4", "Jikuza No. 1", "Hungary No. 4" and so on. Sunflower can choose "Bai 97-1", "inch to eat", "Changling big to eat" and so on. The advantages of these varieties are disease resistance, few branches without branching, high yield and good marketability. Third, the method of seed selection. In the middle and later stage of sunflower growth, combined with forking and artificial pollination, the plants with no decentralization, no disease and insect harm, the same appearance as this variety, the same plant height and maturity, and moderate disk size were marked (also known as station pole head selection). Harvest separately at harvest. Which part of sunflower is good to choose? In a medium-sized (19 cm in diameter) sunflower plate, there are 28 circles of about 1700 seeds, which part of the seed is better to make seeds? The experiments of scientific research departments show that the fruit in the outer circle of the disk has full grains, but after making seeds, the root system of the plant is underdeveloped, the whisker root is short, the root hair is less, the ability of absorbing water and fertilizer is low, and it is not drought resistant and easy to lodge; although there are many fruits in the inner circle of the disk, but the seeds are small, the germination rate of seeds is low, and the seedlings are irregular and slender. The fruit in the circle part of the disk has moderate grains, medium size, full fruiting and high nutrient content. taking this part of the fruit as seeds, the seedlings grow strong, the plant roots are developed, and the shell rate is low and the oil content is high. Thus it can be seen that the fruit in the middle circle of the sunflower plate is best reserved for seeds. Fourth, harvest at the right time. About 7 weeks after the peak flowering period of sunflower, the plastic material no longer increases, the physical properties stop changing, and the seed water content has decreased to about 30%. From the external morphology, the stem, the upper leaves of the plant and the back of the disk turn yellow, the ligulate flowers turn yellow-brown, the tubular flowers fall off, and the husks become hard. When they reach the mature stage, they should be harvested in time. Fifth, store and keep well. When the moisture content of the seed reaches 8%-9%, store it in a bag. The winter temperature is kept at 3 ℃-7 ℃ and the summer temperature is no more than 25 ℃. In this way, the seed germination rate can be maintained at about 95% in 1-3 years. It fell to 85% Mel 95% in the fourth year and 57% to 85% in the fifth year. Therefore, the storage life of sunflower seeds should not exceed four years.