Seed collection, storage and seedling raising techniques of Pinus koraiensis

1. Seed collection and conditioning

Pinus koraiensis is a monoecious tree species. Its flowering period is in the middle and late June. It takes 15 months from flowering to cone maturity. The seed collection period of Pinus koraiensis can be as long as 4 months. The cones can be picked up or dropped from trees in the early stage and picked up from snow in the late stage. After the cone is collected, it can be spread out and dried for several days. When the scales are slightly opened, it can be artificially beaten. The seed rate of cone in natural forest was 13%~14%, and that in artificial forest was 30%. The 1000-grain weight was 520 g. In order to ensure seed quality and high yield of seedlings, we should pay attention to the selection of cones and screen out small seeds in the process of seed preparation. Seeds should be dried to reduce their moisture content to 10% before storage.

2. seedling raising method

Seed treatment, first of all to clean seed, Korean pine seed large, high sowing rate per unit area, generally a seed per square meter 0.5 kg. Generally, it is planted with clean water for 24 hours, removing the floating seeds and retaining the sinking seeds. Second, seed disinfection, Korean pine seed germination time is long, if not disinfected, easy to cause seed mildew rot, before disinfection, first soak seeds, then soak seeds with 0.5% sulfuric acid solution for disinfection for 3 hours, remove seeds to control drying, ready to mix sand germination. The third is seed germination, Korean pine seed dormancy period is long, without full germination treatment, spring sowing in the same year does not emerge or not neat.

Indoor natural temperature accumulation method. In the middle and last ten days of August, the seeds are soaked for 2 days, mixed with sand twice, kept at 60% humidity, piled into 30 - 40cm high in the room, turned once every other day, watered when dry, piled into 60cm high when the weather is cold and frozen, and watered and frozen, and turned before sowing in spring to make the temperature and humidity uniform.

Rapid germination method. 40 days before sowing, soaking seeds in hot water of 50 DEG C, fully stirring until the water temperature drops to 30 DEG C, changing cold water after 24 hours, changing cold water once every two days, soaking for 10 days, taking out seeds when the seeds become milky white, uniformly mixing with wet sand of 3 times volume, putting in leeward and sunning, piling seeds in piles every night, covering with straw curtains, spreading the seeds again the next day, heating the seeds properly indoors in order to accelerate germination time, Keep the temperature at 20~30 degrees, turn twice a day and water evenly to maintain a certain humidity.

The above two methods, when the seed has more than 30% crack mouth, that is, good germination, can be used for sowing.

Sowing time and method, when the spring underground 5 cm temperature reaches 8 degrees above can be sown. Sowing quantity (calculated by dry seed) 200~250 kg per mu, sow the seeds on the bed surface with a seeder, and then suppress them to make the seeds closely contact with the soil, then cover them with humus soil or sawdust after twice the seed grains, and then suppress them again. If sawdust is used, water must be poured thoroughly.