How to Virus-Free and Increase Yield in Potatoes? Key Technical Points Explained

The potato (scientific name: Solanum tuberosum) belongs to the Solanaceae family as a perennial herbaceous plant, its tubers are edible, and it is the world's third most important food crop, after wheat and corn. The potato is also known as earth egg, tudou, foreign taro, etc., and is the tuber of a Solanaceae plant. Together with wheat, corn, rice and sorghum, it is known as one of the world's five major crops.

Growing conditions for potatoes Potato planting siteThe potato prefers cool conditions and is a crop that likes low temperatures. The formation and growth of its underground tubers require a loose, airy, cool and moist soil environment. The potato's temperature requirements: the optimum temperature for tuber growth is 16°C~18°C; when the soil temperature is above 25°C, the tubers stop growing; the optimum temperature for stem and leaf growth is 15°C~25°C, and growth stops above 39°C. The potato has a history of only a little over three hundred years since being introduced to China. It is said to have been introduced by overseas Chinese from Southeast Asia, and in the 21st century China's potato planting area ranks second in the world. Potatoes have high yields, are nutritious, and have strong adaptability to the environment, and are now found all over the world; tropical and subtropical countries can even cultivate them in winter or the cool season and obtain relatively high yields. How potatoes are made virus-free  Potatoes are nutritious and store well. Their growth period is short and their yield-increasing potential is great, making them popular to eat. However, potatoes are easily infected by many kinds of viruses, which causes tubers to become smaller, deformed, and seed potatoes to degenerate. Experiments have shown that using shoot-tip tissue culture combined with virus testing to produce virus-free potatoes, and then producing virus-free seed potatoes for production, can effectively prevent seed potato degeneration and greatly increase potato yields. The main virus elimination methods are as follows: 1. Sampling and disinfectionSprout the tubers of the variety to be made virus-free; when the sprouts are 4-5 cm long, cut the sprouts and remove the outer leaves, rinse under running water for 40 min, disinfect in a sterile room with bleaching powder solution, then rinse 2-3 times with sterile water.

2. Excision and inoculationIn a sterile room, under a 40x dissecting microscope, excise the shoot tip with 1 leaf primordium and inoculate it into a test tube of MS shoot-tip culture medium. The MS shoot-tip culture medium in the test tube includes macroelements, microelements, organic components, auxin, cytokinin, sucrose and agar, with a pH value of 5.7; it is used after high-pressure sterilization, and 1 shoot tip is inoculated per test tube.

3. Culture conditionsThe inoculated shoot tips are cultured in a culture room at 25°C under 1500-3000 LX light conditions, and in 3 months they grow into small plantlets with 3-4 leaves. Under sterile conditions, cut and propagate once, and take some plantlets for virus testing.

4. Virus testingVirus testing is an indispensable step in shoot-tip virus elimination. It is commonly carried out using indicator plants, i.e. differential hosts, or serological methods, promptly eliminating shoot-tip plantlets that are serologically positive or show symptoms on indicator plants; shoot-tip plantlets with no reaction at all are virus-free plantlets and are used for propagation.

How to increase potato yields

1. Remove tail buds: Tests have shown that after potato tail buds grow into plants, the yield is only 1/3 that of plants grown from terminal buds or lateral buds, so when cutting seed potatoes, tail buds should be discarded and not used.

2. High-ridge cultivation: High-ridge cultivation with soil hilled up on both sides can increase the loose soil in the root and stem zone of the active soil layer, which is beneficial for stolon extension, and can also raise the ground temperature to meet the temperature needed for early root and stem development.

3. Formula fertilization: Potatoes need large amounts of nutrients throughout their growth and development period. In areas with poor soil and low nutrient content, formula fertilization must be used to meet the crop's needs for nitrogen, phosphorus, potassium and trace elements during growth and development, especially during tuber expansion, which can greatly increase yields.

4. Remove flower buds: The part of the potato that can be used is the underground tuber, which does not need flowering and pollination at all to form, and bud formation and flowering also consume large amounts of nutrients. To obtain high yields, buds must be pinched off as soon as they are seen, to save nutrients and promote tuber growth.

5. Less hoeing, more direct furrowing: The fleshy roots of potatoes that can form tubers grow horizontally in the soil, and deep hoeing often cuts the fleshy extension roots, artificially causing reduced yields. Therefore, after the first hoeing, only furrow without hoeing, combining furrowing to press down weeds with manual removal to prevent weed infestation, which can effectively increase yields.

6. Supplement magnesium to boost production: Expert research has shown that during the potato's growth process, especially during tuber expansion, if magnesium fertilizer is sufficient, not only is the yield high, but starch accumulation is also greater and the quality is good. Therefore, when the plant is 45 cm tall, dissolve 500-100 g of magnesium sulfate in water per plant and apply it as a top dressing.

7. Foliar spraying: Under the condition of applying sufficient base fertilizer, starting from leaf expansion, spray the leaves once every 10 days with a mixture of 0.1% magnesium sulfate, 0.3% potassium dihydrogen phosphate, and 1000-fold triacontanol, spraying 3-5 times in succession, which can significantly increase yields. If supplemented with other measures such as sunning the seed potatoes, soaking seeds in rice alcohol, keeping only one strong sprout per plant, and breaking off small seedlings to fill gaps and ensure a full stand, the yield will increase further.