Seed treatment techniques of Pinus koraiensis

Pinus koraiensis (PonusRoraiensisSiebetZucc.), also known as Pinus koraiensis, Pinaceae. It is growing well in Kuandian area of Liaoning Province, and its wood material is soft and durable, edible and squeezable oil. it is a natural green food. In recent years, with the increase of the export volume of Korean pine seed kernel products, the commodity value of Korean pine is getting higher and higher, and the demand for Korean pine afforestation seedlings is also greatly increased, thus arousing the enthusiasm of the majority of seedling workers to raise Korean pine seedlings.

In the process of Korean pine seedling cultivation, seed treatment is the key step, and the seedling emergence rate, seedling yield and seedling quality are all related to the quality of planting treatment, combined with the climatic conditions and years of seedling raising experience in Kuandian area. several treatment methods, seed selection and sowing of Pinus koraiensis seeds are introduced as follows, which can be used as a reference in seedling production.

I. seed selection

In the seedling raising project in Kuandian area, the excellent seeds in the central area of Caohekou should be selected, and the seeds of Huangyi Mountain seed Orchard in Kuandian can also be used, and the seeds can be selected from more than 30-year-old Pinus koraiensis mother forest and clonal seed orchard of Pinus koraiensis. Pinus koraiensis seeds produced by superior trees in the forest should be collected after September 20.

2. Seed treatment

1. Overwintering mixed sand burial method

Select a storage pit in a shady place with high topography and good drainage. The width of the upper mouth of the pit is 1.0 meters, the width of the bottom is 0.8 meters, and the depth is 1.3 meters (the bottom of the pit should be sand and gravel bottom). The length depends on the amount of seeds stored. Clean fine river sand was selected from October 20th to November 10th, and the planting sand volume was mixed according to the proportion of 1:3. If the seeds were collected before September 20, the seeds should be soaked for 3 days before mixing to remove the immature seeds floating on the water surface so that the seeds can absorb enough water. During storage, the water content of the sand is held by hand, but without dripping, it is appropriate to loosen the hand. Put 20cm thick fine sand at the bottom of the pit, pile the sand mixture on top of the fine sand, pile it to 25cm above the surface and then fill it with river sand, and then use fine soil to pile it into a mound above the pit, which is 80-100cm high. Tie the defoliated corn stalk into a breathable handle with a diameter of 15cm, and put a bunch every 2-4 meters in the storage pit for ventilation. In the middle of March in spring, cover the seed cellar with shade net or corn straw to prevent the seeds from blooming prematurely. After the seedbed is done, take out the seeds 2 days before sowing, sift the fine sand and put it in the shade to prepare for sowing. If the seed crack is less than 40%, it can be turned and mixed in the sun until the crack reaches the standard.

This method is labor-saving, convenient and easy to operate, so it is widely used.

2. Fast forward sprouting method

Soak the seeds in cold water for 2 days about 40 days before sowing, remove the immature seeds floating on the water surface, remove the remaining seeds, disinfect them with 2% sulfuric acid adit or 3% quicklime emulsion, soak them out after 3 hours, pour the seeds into the tank, soak the seeds in warm water of 45 degrees Celsius, stir with the water, and stop stirring when the water temperature drops to 20 degrees Celsius. Don't throw away the seeds that surfaced, they will sink after a few days of soaking. After a week of soaking, when the kernel is close to the inner wall of the outer seed coat, it means that the seed soaking is moderate. If the seed does not reach this standard, the seed should be soaked continuously and the water should be changed every 2-3 days during the soaking period.

After moderate seed soaking, pick out the seeds in the leeward direction of the south side of the building, mix the seeds with fine wet sand according to the volume ratio of 1:3, and stack the sand mixture in a way that is high in the north and low in the south, 60cm on the north side and 20cm on the south side, with the length determined by the number of seeds, the sand mixture is surrounded by wood boards, flattened out and covered with plastic sheeting to cover with straw curtains or corn stalks in the evening to keep warm. The first half of the treatment is stirred every 2-3 days, and the second half is once a day, in order to ensure that the seed temperature and temperature of the upper and lower layers are consistent. If there is a lack of water, it is appropriate to keep the sand temperature at 60%. Remove the plastic sheet 5-6 days before sowing. After the bed is made, take out the seeds 1-2 days before sowing, sift the sand and put it outside the shade to prepare for sowing. If the seed crack is less than 40%, it can be stirred in the sun or soaked in gibberellin.

This method can be used when the seeds are transferred late, the ground has frozen and there is no permanent seed cellar. The practice shows that the seeds treated by this method emerge early, evenly and evenly, but it takes a lot of work.

3. Mixed burial treatment of kinds of ice and sand

Prepare wet river sand before treatment, small ice cubes and large ice cubes of 6-10cm, mix seeds, small ice cubes and wet river sand according to the volume ratio of 1:2:2 into seed cellar, put a layer of large ice cube on top of the ground when 30cm is high, and put wet river sand with 10cm thickness on top of the ice cubes. In weather conditions below-15 degrees Celsius, freeze the smoothie mixture for 8 days, then cover with 20cm thick wet sand, cover the sand tightly with corn straw to prolong the freezing time, take out the mixture 15 days before sowing, promote germination in indoor or outdoor greenhouse, keep it moist, turn and mix once a day, 40% split mouth can sow seeds.

In terms of time, this method is between the winter storage method and the rapid budding method, and can be carried out around the fifteenth day of the first lunar month, with a ready-made seed cellar.

Third, sowing seeds

After the nursery bed is finished, the seeds can be sown. In order to ensure the uniformity of seedlings, the seeds should be evenly distributed before sowing and sowed. The sowing rate is 150-165kg/ mu, and immediately after sowing, sand cover, re-suppression and sand cover thickness 2.0cm.