Identification and Prevention of physiological Diseases of Atlantic Potato Tuber

Atlantic potato is a high quality raw material for processing and producing snack foods such as potato chips and French fries. it has a relatively short growth period and strict requirements on the cultivation environment, both cold and not resistant to low temperature. in order to avoid black heart disease, hollow heart disease, starch overflow, crack, deformity and other physiological diseases, and improve the quality and commodity rate of tubers.

1. Black heart disease of tuber

1. Symptoms: irregular patterns from black to blue appear in the center of the tuber. When the hypoxia is severe, the whole tuber may turn black. Usually, the boundary between diseased tissue and healthy tissue is obvious. This is caused by lack of oxygen inside the tuber.

2. Prevention: mainly pay attention to maintain the good ventilation of the potato pile during storage, and maintain the appropriate storage temperature. The room temperature must be kept between 1 ℃ and 3 min, the relative humidity should be kept below 85%, and the air should be well ventilated. During storage, different varieties should be stored separately, not mixed with seeds and chemical fertilizers, and should not be put in places with high smoke and gas, so that potatoes will not become moldy and sprout.

2. Hollow heart disease of tuber

1. Symptoms: hollow heart disease mostly occurs in the medulla of tuber, without any symptoms. In general, large tubers are prone to hollow phenomenon. Most of the voids are star-shaped, radial or flat-shaped, and sometimes several holes are connected. The walls of the cave are white or brown. Before the hollow appeared, the tissue was waterlogged or transparent. Cracking is caused by the increase of internal tissue tension, some of which are transferred or absorbed by other parts. The hollow is caused by the rapid expansion of tubers.

2. Prevention: the main measures are to maintain appropriate soil moisture during the tuber expansion period, and to reasonably close planting, increase the application of potassium fertilizer, and pay attention to soil cultivation. Atlantic potato needs a large amount of fertilizer, so it is necessary to apply sufficient base fertilizer, which accounts for 50% to 60%, mainly organic fertilizer and phosphorus and potassium fertilizer. Organic fertilizer needs more than 1500mur2000 kg per mu. During the whole border, the chemical fertilizer is selected to be sulfur-containing compound fertilizer with a nitrogen, phosphorus and potassium content of 15%, 50kg per mu. Before sowing, ditch or hole application is applied in the middle of the border, and attention should be paid not to directly contact the seed potato so as not to burn the seed potato. Topdressing should be carried out early and skillfully, generally divided into two stages. For the first time, topdressing is carried out at the full seedling stage, and thin human feces and urine can be used to ensure the nitrogen fertilizer needed for the growth of potato seedlings and lay a good foundation for the growth of potato seedlings in the middle and later stages. 500 kg of mature human feces and urine were poured with water combined with mid-tillage. The second time is in the budding stage, when the potato tuber begins to expand and the amount of fertilizer is increased, which is the period when the potato needs the most fertilizer, mainly potash fertilizer, combined with appropriate amount of nitrogen and phosphorus fertilizer to meet the needs of tuber. Attention should be paid to suitable nitrogen and potassium in fertilization to prevent seedlings from growing under light and not producing potatoes. If too much nitrogen is applied, the overgrowth can be inhibited by spraying 0.02% magnesium sulfate solution, and the compound fertilizer can be applied to 5kg / mu. After the ridge is closed, you can no longer apply fertilizer. In the whole growth process, it is generally required to plough 2mi for 3 times, and to carry out the first deep ploughing combined with interseedling in order to increase the soil temperature and promote seedling emergence, and to carry out the second intermediate ploughing and shallow soil cultivation at rosette stage to benefit more tubers. The third time of ploughing and soil cultivation was carried out before the ridge was closed. The cumulative soil thickness was 10 ~ 20 cm and the height of the border was 35 ~ 40 cm. The soil cultivation could thicken the tuber layer, effectively increase the yield, prevent the potato pieces from turning green and reduce the quality.

Starch overflow and tuber cleavage

1. Symptoms: "white spots" or "pimples" or potato skin ulcers can often be seen on the surface of some tubers during harvest; some tubers show one or more longitudinal cracks, and the surface is covered by healed periderm tissue, which is the crack of tuber, which varies in width and width, which seriously affects the commodity rate. In the rapid growth stage, the tuber could not be irrigated and fertilized in time due to drought, or under the conditions of high temperature, high humidity and high temperature and drought for a long time, the starch of the tuber overflowed to the epidermis, resulting in "white spots" or "pimples" or potato skin ulcers; some cracks occurred because the internal pressure exceeded the bearing capacity of the epidermis, and the cracks widened gradually with the expansion of the tuber. Sometimes the cracks gradually "flattened", and only "traces" were seen during harvest. The main reason is that the soil is suddenly dry and wet, the tuber forms the periderm during drought, the expansion rate is slow, the plant absorbs more water when it is wet, and the tuber expands quickly, which makes the periderm break. In addition, during the expansion period, the soil fertilizer and water is too large, which is easy to cause cracks in the outer skin of potato blocks.

2. Prevention: mainly to increase the application of organic fertilizer to ensure that the soil fertility is always uniform; at the same time, timely watering to ensure that the soil has appropriate water content in the tuber expansion period to avoid soil drought; but also to maintain good soil permeability. Generally, we can adopt high border cultivation, dig deep edge ditches, the depth of the ditches should be more than 50 cm, and the ditches are interlinked, and the stagnant water in the field can be drained quickly in case of rain. at the same time, weeds in the fields should be prevented, and ditch and waterlogging prevention should be carried out frequently before the rainy season.

IV. Tuber malformation

1. Symptoms: most of the malformed tubers are formed by the second expansion of tubers. There are many types of deformities, including tumor tubers, that is, protruding in the bud eyes of tubers to form tumor-like tubers; dumbbell-shaped tubers, that is, forming "thin neck" near the top of tubers; secondary tubers, that is, forming new branches and leaves on tubers; and chain-like secondary growth, that is, growing stolons on tubers and forming tubers. The main reason for secondary growth is the alternation of high temperature, drought and high humidity, or the weather returns to normal after freezing injury. Any external conditions that can cause the tuber not to develop normally can cause the tuber to produce deformity.

2. Prevention: it is mainly to maintain suitable conditions for tuber expansion, that is, to increase the application of organic fertilizer to increase soil fertility; to properly plough deeply, pay attention to middle ploughing and prevent frost damage, to maintain good soil permeability; to keep the soil moist, and to pay attention to watering during drought.