2, seedling stage, unearthed seedlings, experienced root development, and the main stem was pregnant at seedling stage. Because seed potato is rich in nutrition and water, a considerable number of roots and embryonic leaves are formed before emergence.
3. Tuber formation period: from the time of tuber formation, the first inflorescence begins to blossom, and the top of stolon of the whole plant begins to expand until the maximum tuber diameter reaches 3-4 cm, and the dry weight of stem and leaf in the upper part of the underground reaches a balance with the dry weight of tuber.
4. The tuber growth period, that is, from the re-balance of dry matter above ground and underground, enters the tuber growth period, when the leaf area has reached the maximum, and the growth of stems and leaves gradually slows down and stops; The nutrients produced on the ground are continuously transported to the tuber, and the volume and weight of the tuber are increasing.
5. During the starch accumulation period, the stems and leaves gradually aged, and the tuber volume and weight continued to increase. The growth characteristic of this period is that the aboveground parts transport carbohydrates, protein and ash to tubers, and the weight of tubers is the largest day by day.