Seed selection and cultivation techniques of Chinese Cabbage

1. What is a local variety? What are its advantages and disadvantages? A: the local varieties of Chinese cabbage are cultivated for a long time under the local specific ecological environment through natural selection and artificial selection. Therefore, it has a strong adaptability to the environment of origin, and the commodity is also suitable for the needs of the local market. In history, vegetable farmers have a habit of keeping their own seeds for local varieties. Because Chinese cabbage is a cross-pollinated crop, the phenomenon of variety degradation is particularly prominent. two。 Why can conventional species retain the second generation, while hybrids can not? A: conventional species are produced by artificial selection in a fixed population from generation to generation. So there is not much difference between the second generation and the first generation. The hybrid generation is produced by the crossing of two parents. In contemporary times, it is neat and disease-resistant. On the other hand, the second generation after self-breeding is a separate generation, its genetic background is very complex, the field performance is very separated, the plant is seriously irregular and loses its economic value. 3. What is a hybrid? What are the characteristics? A: a hybrid refers to the offspring produced by crossing between a selected male parent and a female parent. The hybrids were obviously superior to their parents in growth vigor, vitality, fecundity, stress resistance, yield and quality. Its advantage is not only the outstanding performance of one or two characters alone, but also the advantage in many aspects. 4. What are the characteristics of nuclear gene interaction male sterile lines in Chinese cabbage? Answer: A. This technique is the most advanced breeding technology at the present stage. This technology fills the gap in science and technology in the world. b. The purity of the hybrid can reach 100%. Because the female parent is 100% sterile, the hybridization rate can reach 100%. It has strong heterosis, outstanding disease resistance and a wide range of adaptation. 5. What is the economic value of growing Chinese cabbage? Answer: 1. The yield of Chinese cabbage is high, the production cost is low, and the output value is 2-6 times that of the field. the planting method is simple and the grower is easy to master. The selling price is low, and it is easily accepted by ordinary consumers. two。 Chinese cabbage is resistant to storage and transportation. Can solve the problem of annual supply of vegetables, 3. Chinese cabbage can also be processed and pickled in addition to direct consumption. 6. What is the nutritional value of Chinese cabbage? a: Chinese cabbage contains a variety of nutrients, which is an important source of vitamins, inorganic salts and edible cellulose necessary for human physiological activities. Chinese cabbage is rich in calcium, which is 5 times higher than tomato and 1.9 times higher than cucumber; ascorbic acid (vitamin C) is 4 times higher than cucumber and 1.4 times higher than tomato; carotene is 1.8 times higher than cucumber. Chinese cabbage is a healthy food to prevent cancer, diabetes and obesity. An American scientific research institute specializing in cancer has found that "eating more cabbage can prevent cancer." It is recorded in the Compendium of Materia Medica in ancient China that Chinese cabbage also has very good medicinal value: it has the functions of flat taste, relieving fever and removing annoyance, invigorating the intestines and stomach, tonifying the middle and digestion, diuresis, clearing the lungs and relieving cough, relieving thirst and relieving diarrhea. 7. How to preserve Chinese cabbage seeds for a long time? A: the water content must be reduced to less than 8%. It can be preserved for 3-4 years under low temperature and dry condition. 8. How to distinguish between new seeds and old seeds of Chinese cabbage? Answer: the new seed has a smooth skin, pressed with fingernails into a cake, more oil, light yellow or yellowish green cotyledons. On the other hand, the skin of the old seed is dark and dull, and there is often some "white frost". It is easy to crush with fingernails and the seed coat is easy to fall off, with less oil, and cotyledons are dark yellow. if more crushed, you can smell hala. 9. How to choose spring heading cabbage? What should be paid attention to in cultivation management? Answer: choose precocious varieties with strong winter, cold resistance, bolting resistance and short growth period, and you should read the variety description carefully when you buy it. Note: 1. Avoid low temperatures. Keep the temperature at the seedling stage to prevent vernalization from being completed prematurely. two。 There is a great flood and fat. Cultivate on fertile soil, apply a large amount of available base fertilizer and topdressing at the initial stage of heading, the water supply is sufficient to promote its rapid growth and prevent bolting. 3. Highly close planting. In order to remove early moss plants, leaving a sufficient number of plants to ensure yield, while early prevention and control of diseases and insect pests. 10. How to choose summer heading cabbage? What should be paid attention to in cultivation management? Answer: choose early-maturing varieties with high heat resistance and high temperature pelleting. Note: 1. The previous crop must mature early in order to prepare the soil in time. two。 The key to cultivation is to promote its rapid growth, so it is necessary to apply adequate base fertilizer. 3. The temperature is high in summer, so we should try our best to cool down and protect seedlings. The main measure is to often pour small water to reduce the soil surface temperature. 4. Topdressing uses quick-acting fertilizer and liquid fertilizer at the same time. Make sure that there is enough fertilizer and water, and do not squat seedlings. 5. During the heading period, it is appropriate to dung frequently, so that its rapid growth to maturity. 11. What kind of Chinese cabbage is good for storage? Answer: the straight tube type is more resistant to storage than the spherical type, the green gang system is more resistant to storage than the Bai Bang system, the middle and late maturing varieties are more resistant to storage than the early maturing varieties, and the cabbage with "80% heart" is more resistant to storage than the Chinese cabbage with compact balls, and the cabbage without diseases and insect pests is more resistant to storage than the cabbage with diseases and insect pests. twelve。 How to store Chinese cabbage? Answer: Chinese cabbage is generally stored in greenhouse cellar. The cabbage should be irrigated 10 days before harvest and should be dried on the spot for 2-3 days after harvest to wilt and soften the outer leaves so as to reduce the damage during transportation, then remove the rotten leaves and store them on the spot and store them in the cellar before the cold current comes. Cabbages are stacked neatly in the cellar. Generally, the length of the cellar is stacked against two walls, with 4 rows of vegetables in each pile, the tips of the outer 2 rows facing outward, and the tips of the middle two rows facing inward, with a total of 7-10 layers of cabbages. With a height of 1.5-2.0 meters, it is best for each row of cabbage to have a layer of corn stalks if possible, so that the cabbage pile can be ventilated, dissipated heat, reduce decay and debonding, save labor, and improve the rate of exhumation. In addition, leave a space of 2 meters at one end of the pile in order to pour vegetables. Per cubic meter shed cellar, store 300-400 kilograms of vegetables. 13. How to manage Chinese cabbage during storage? A: the suitable conditions for the storage of Chinese cabbage are that the pit temperature is about-2 ℃ and the humidity is about 85%. In order to reduce the consumption in the process of storage, it is necessary to prevent heat in the early stage, freeze in the middle stage and rot in the later stage. Early stage: after Chinese cabbage enters the cellar, the pit temperature and vegetable body temperature are higher, so it is necessary to strengthen the ventilation and dehumidification of the vegetable cellar. The cabbages should be poured frequently to prevent the vegetables from heating up and getting out of hand. Mid-term: in the first and middle of January, the temperature dropped obviously, and the greenhouse cellar should be covered with grass, gunny bags and other heat preservation and anti-freezing. In the later period, the temperature rises again in March and April, so it is necessary to prevent the warm wind from blowing into the cellar. Attention should be paid to the discharge of moisture, and the common frost on the top of the cellar should be cleaned to prevent water droplets from rotting on the vegetables. At the same time, rodent damage should be controlled in the shed cellar. 14. How to control diseases of Chinese cabbage by seed disinfection? Answer: downy mildew: 1. Select seeds with 10% brine, remove blighted grains, wash them with clean water after selection, dry and sow seeds. two。 Mix the seeds with 50% thiram wettable powder or 75% chlorothalonil wettable powder, the dosage is 4% of the seed weight. Soft rot: 1. The seeds were soaked with 45% Dysenamine water agent 400 times. two。 Mix the seeds with Fengling and sow the seeds immediately after mixing well. 15. What are the symptoms of downy mildew of Chinese cabbage? Under what circumstances is it easy to happen? How to prevent and cure? Answer: symptoms: when young seedlings, brown dots or sunken spots are formed on the cotyledons, and white mildew layers appear on the cotyledons and stems when it is wet. In the true leaf stage, polygonal yellow spots appeared on the front of the true leaves, and a white mildew layer appeared on the back of the leaves when it was wet. When the disease spot is long, the interconnection can cause the withering of the leaves in a large area. The diseased leaves develop from the outside to the inside, and in severe cases, the plants are not covered with heart. Occurrence: early sowing, poor ventilation, continuous cropping field, insufficient bottom fertilizer, lack of fertilizer in pericarp period, too late interseedling, excessive seedling density, serious virus disease and slow growth are all beneficial to the development and epidemic of downy mildew. Control: A. select disease-resistant varieties. Such as Green Star 70, Green Star 80, Fukuda 70, Fukuda 80 and so on. These varieties do not need to be treated with any fungicides throughout the growth process. B. disinfect seeds, select plots, sow at the right time, and control in time. C. strengthen field management, such as squatting seedlings should not be too long, reasonable irrigation and fertilization, clean the countryside after harvest, turn deep in autumn. D. Drug control, such as 75% chlorothalonil wettable powder 600 times liquid; 40% ethyl phosphorus aluminum wettable powder 150-200 times liquid. 16. What are the symptoms of Chinese cabbage virus disease? Under what circumstances is it easy to happen? How to prevent and cure? Answer: symptoms: seedling onset, the new leaves first along the vein chlorosis, and then gradually appear yellow-green flowers and leaves, leaves wrinkled uneven, become brittle, heart leaves twisted deformity. Adult disease, leaves become hard and brittle, mosaic, necrotic disease spots appear, serious can not be wrapped. Occurrence: in general, the disease in the field of adjacent cropping and continuous cropping of cruciferous vegetables is serious, while the land with good soil quality and fertile water conditions is light, the disease of early sowing is serious, the disease of timely and late sowing is mild, the high temperature and drought weather is serious, and the low temperature and humid weather is mild. In addition, Qingbai varieties are more resistant than Bai bang varieties. Prevention and treatment: A. select high-yield and disease-resistant varieties, such as Lvxing 70, Lvxing 80, Lvfeng No.1 and Lufeng No.2. Wait. B. early release, spraying insecticides before soil preparation and seedling stage to eliminate virus-transmitting insects. C. sowing at the right time, there can be no shortage of water in the seedling stage. D. Drug control: virus A _ (1) 300-fold solution, antiviral agent 1, 200-300 fold solution. 17. What are the symptoms of soft rot of Chinese cabbage? Under what circumstances is it easy to happen? How to prevent and cure? Answer: symptoms: generally appear in the heart of Chinese cabbage, the initial petiole base oval spots, gradually expand and become soft, showing dark gray. In severe cases, more than half of the leaves rot, giving off a bad smell, and finally, the whole plant falls down and dies. Cabbage is the most serious. Occurrence: variety differences, straight tube cabbage disease resistance than cabbage; serious insect pests, the disease is serious; low temperature and humid climate is easy to occur; continuous cropping, flat bed cultivation and sowing early are easy to occur. Prevention and treatment: A. Select disease-resistant varieties. The first choice for cabbage is Futian 70 and Futian 80. It has been proved by production for many years that this variety has high resistance to soft rot, which is obviously better than other similar varieties. b. Avoid continuous cropping. c. Drug prevention and treatment, 200PPM streptomycin or neophytomycin; 50% thiram wettable powder 800x solution. 18. What symptom does Chinese cabbage dry burn heart disease have? Under what circumstances is it easy to happen? How to prevent and cure? A: symptom: it is a disease in the heading stage of Chinese cabbage. The growth of outer leaves is normal, while part of the leaves in the bulb become dry and yellowed from the leaf margin, and the mesophyll is translucent and paper-like, resulting in dry heartburn of Chinese cabbage, which is not tolerant to storage, the quality decreases, and loses edible value in serious cases. And easy to cause decay, mildew and other phenomena. Occurrence: varieties are not resistant to disease. In addition, in saline-alkali soil, the disease occurred seriously under the condition of excessive application of nitrogen fertilizer, high cultivation topography and uneven watering. Prevention and control: select new varieties, improve saline-alkali soil, increase the application of organic fertilizer, and pay attention to crop rotation. In addition, from the rosette stage, 0.7% calcium chloride plus 50PPM naphthylacetic acid was sprayed on the leaves, once every 7-10 days, 4-5 times continuously. 19. What harm do aphids do to Chinese cabbage? How to prevent and cure? Answer: harm: 1. Aphids suck the sap of leaves, causing leaves to curl and turn yellow. two。 Spread viral disease. It makes the plant grow slowly, and finally the whole plant wilts and dies. Prevention and control: reasonable land use, avoiding continuous cropping, early soil preparation, cleaning the countryside, spraying insecticides once before ploughing; chemical control: 1000-2000 times of 40% dimethoate EC or 2000-3000 times of aldicarb wettable powder, once a week, 2-3 times continuously. 20. How to control cabbage worm (Pieris rapae)? Answer: clean the field in time, eliminate the residual plants and leaves in the field, and avoid continuous cropping; chemical control: 1000 times of trichlorfon crystal, 25% and 30% diflubenzuron 1 or 3 500-1000 times. 21. What is the harm of cabbage armyworm to Chinese cabbage? How to prevent and cure? Answer: harm: in infancy, gnawing on the back of the leaves, leaving behind the epidermis to form dense membranous transparent holes. The third instar larvae gradually disperse the harm, can eat the leaves only leaves veins, and can eat into the leaf ball to eat, the leaf ball will eat flowers empty, and leave a lot of feces. Prevention and cure: turn the land deeply at the beginning of winter, and you can also use black light and sweet-and-sour wine venom (3 parts of brown sugar, 1 part of wine, 4 parts of vinegar, 2 parts of water and a little trichlorfon to mix well, put it in a basin and put it on a shelf 1 meter high from the ground. Put a basin every 3-5 mu) to trap and kill adults. Chemical control: should be carried out in advance, focus on spraying the back of the leaf and the middle and lower leaves. Use the same potion as the cabbage worm. twenty-two。 How to distinguish Chinese cabbage nutrition disorder? A: the symptoms of malnutrition in Chinese cabbage are as follows: nitrogen deficiency: slow growth, short plant, yellow leaves, slender stiff parts, unsubstantial nitrogen deficiency leaves, increased leaf fiber and decreased quality. Phosphorus deficiency: the leaf color becomes darker, the leaf is small and thick, and the leaf burr hardens and stings in the hand. After that, the outer leaves gradually turn yellow and the inner leaves are dark green. Potassium deficiency: browning and dying from the lower leaf margin, gradually developing to the medial or upper leaves, the lower leaves withered, and the ability to resist soft rot and downy mildew decreased. Iron deficiency: the outer leaves are green, the inner leaves turn yellow gradually, and then the new leaves are obviously yellow and white, and the plant type becomes smaller. Boron deficiency: the midvein of the outer leaf is cracked and necrotic, and the heart leaf turns dark green in advance, shrinks, and then turns yellow and brown until all rot. Calcium deficiency: dry heartburn, characterized by withered growth point, necrosis of leaf edge tissue, grayish-white leaf tip and leaf edge, with obvious dry edge. When it is serious, it is not easy to bear the ball. 23. What should I pay attention to when buying cabbage seeds? Answer: 1. Choose a reputable unit to buy. two。 Buy formal brand seeds that have been tried in the past, preferably those produced by scientific research institutes and institutes. Is there a trademark on the package at the same time? If it is marked, it indicates that the trademark is registered by the State Trademark Office and is a formal enterprise brand. 3. When buying, see the production date (Chinese cabbage seeds are dried at low temperature, the shelf life is 3-4 years). 4. Read the instructions in detail. If the description does not mention that it can be planted in spring, it should not be regarded as a variety of spring heading.