First, the developmental characteristics of dormancy
Potato tubers will not germinate for a period of time after maturity and harvest, even if they are given suitable conditions. We call this phenomenon potato dormancy period, which is also called dormancy period. This is a kind of self-protection for the bad environment formed by potatoes in the process of evolution.
The dormancy characteristics of potato tuber are closely related to production and consumption. The length of dormancy period affects the storability of tuber, whether it can emerge after sowing and yield, which is often the main influencing factor of high yield.
The length of dormancy period varies with varieties and storage conditions. Under the condition of about 26℃, the dormancy period ranges from 65438 0.5 months to 3 months. Tubers can be dormant for a long time at 0~4℃, and the dormancy period will be shortened with the gradual increase of temperature. The dormancy period of the big stem of the same variety is shorter than that of the small tuber, and the dormancy period of the terminal bud on the same tuber is shorter than that of the base.
Methods of breaking dormancy of potato tuber;
Choose a place that is conducive to germination to accelerate germination. Cut the seed potato into slices, each with 1~2 bud holes, and put it in a cool and ventilated place. A layer of potato blocks and a layer of wet sand layer are stacked and kept moist, and it can germinate in 7~ 10 days. Drug therapy. Gibberellin is widely used at present. Soak the cut tuber in gibberellin solution of 0.5~ 1 ml/L for 5~ 10 minutes, take it out, air dry, germinate in layers, and then sow. You can also soak potato pieces in 0.5%~ 1% thiourea solution for 4 hours, take them out and put them in a closed container 12 hours, and then bury them in wet river sand. Most of them can germinate in about 10 days. Second, the development characteristics of the germination period
From tuber bud germination to bud germination. After the tuber bud germinates, it begins to elongate and grow, and finally forms obvious buds. When the bud was unearthed, the leaf primordium on the main stem had differentiated, and the terminal bud became a flower bud, which was spherical. At this time, the buds in the growth center elongate and take root, forming stolons. The main factor affecting the growth of buds and roots is temperature.
When the temperature is not lower than 4℃, the dormant tuber begins to germinate, but does not elongate. The bud began to germinate at 5℃~7℃, but it was very slow. When the temperature is 10℃~ 12℃, the bud grows vigorously and rapidly, and the optimum temperature is 18℃. When the temperature exceeds 36℃, the buds are not easy to germinate and a large number of rotten seeds are easy to form. In short, buds and roots grow weak when the temperature is too high, and germinate slowly when the temperature is too low. When the ground temperature of the plough layer (0~ 10 cm) is stable at 7~8℃, spring sowing begins in production. When sowing in autumn, high temperature is the main factor affecting the emergence of strong seedlings. In the northern planting area, there is a big sandstorm, little rain and slow temperature rise in spring, mainly for raising the ground temperature, and adopting early sowing and loosening soil to promote early germination, early emergence and strong seedling; In the southern planting areas, it is mainly to reduce the ground temperature, maintain suitable soil moisture, and promote rapid emergence, full seedlings and Miao Zhuang.
Third, the developmental characteristics of seedling stage
From emergence to the sixth or eighth leaf spreading, it is the seedling stage, which is equivalent to the growth of a leaf sequence, so it is also called clump tree, which is the second stage of potato growth. At the seedling stage, the root system continued to grow and develop, and the stem and leaf did not grow much, but the leaf spread quickly, and 1 leaf appeared in about 2 days. In the second growth stage, the stems and leaves in the third stage have differentiated.
Whether planted in spring or autumn, the seedling period is only half a month. Therefore, we should strengthen field management, topdressing as early as possible, promote the rapid growth of seedlings, strengthen ploughing and weeding, and maintain moisture and ventilation.
Fourthly, the development characteristics of trees in the growing period.
It generally takes about 65,438+0 months from heading to 65,438+02 ~ 65,438+06. The first inflorescence of early-maturing varieties blooms, and the second inflorescence of late-maturing varieties blooms.
The development characteristics of this stage are that the stem begins to rise sharply, accounting for about 50% of the total height; The main stems and leaves have been built, and some branches and leaves have spread out. At the same time, the root system continues to expand, and the tuber gradually expands, and the dry weight of tuber has exceeded 50% of the total dry weight of the plant, indicating that the growth at this time has changed from vegetative growth to reproductive growth.
Five, the development characteristics of potato in the fruiting stage
After the completion of the tree-growing stage, it enters the tuber-bearing stage with tuber growth as the main factor. The development characteristics of this period are that the development of stems and leaves is decreasing day by day, the basal leaves begin to turn yellow and fall off, the organic matter in various parts of the plant is transported to the tuber, and the tuber expands rapidly. Especially in the flowering period 10 day, the expansion speed is the fastest, and about half of the yield is formed during this period.
The tuber setting period is generally 30~50 days, and the cultivation should be mainly based on protecting seedlings and attacking potatoes, with sufficient fertilizer and water, appropriate temperature difference between day and night and strong illumination, so as to keep stems and leaves from rotting, promote nutrient production and transport nutrients to tubers, and obtain high-yield and high-quality tubers.
The optimum ground temperature for tuber formation is 16℃~ 18℃. At 25℃, the tuber grows slowly, and at 30℃, the tuber stops growing because the consumption of respiration exceeds the accumulation of nutrients. At this time, all nutrients transported by leaves are used for the growth of buds on tubers. When the local temperature drops due to rainfall or watering, the growing buds on the tuber stop growing and accumulate nutrients again, thus forming seed potatoes and deformed potatoes.
The above are the growth and development characteristics of potatoes in different periods. It is of practical significance to understand the development characteristics of these different periods and use them flexibly in actual planting.