Key Technical Points and Precautions for Saving Seed of Water Dropwort

Water dropwort reproduces asexually, and its stems are the propagation material. For water cultivation, select seed plants in late November. The selection criteria are: possessing the excellent characteristics of the variety being saved, with moderate plant height, thick and sturdy stems, relatively short internodes, numerous and robust axillary buds, a well-developed root system, and freedom from insects and disease. The selected seed plants are then immediately transplanted into the seed-saving field.

The seed-saving field should be chosen in a spot sheltered from the wind and facing the sun, with convenient drainage and irrigation. In mid-October, carry out fine land preparation and apply a thick basal fertilizer. When planting the seed plants, maintain a 1 cm water layer in the field, with both row spacing and plant spacing of 25 cm, and plant 3-4 plants per hole. After planting, maintain a 5-6 cm water layer for 7-8 days. If a strong cold wave occurs, the water layer can be raised to a depth of 15-20 cm, and after the cold wave passes, lower the water layer back to 5-6 cm.

After overwintering, maintain shallow water and frequent irrigation. In April-May, apply compound fertilizer as a top dressing. Thin the seedlings and pull out some tillers to facilitate ventilation and light penetration. In June-July, keeping the field merely moist is sufficient, in order to dwarf the seed plants and prevent lodging. In late spring and early summer, the moss growing in the field affects the rise in water temperature, and some moss even entangles the seed plants, affecting their normal growth. The method for controlling moss is: on a sunny day, drain the field water, after drying the field for half a day, at a rate of 100 g per mu, wrap copper sulfate in gauze and place it at the water inlet, then let water flow into the field, so that the copper sulfate solution is evenly distributed throughout the field with the irrigation water. After 5-7 days, the moss will all be killed.

After June, pest control and other field management tasks must all be carried out on the field ridges; one must no longer step into the field, so as to avoid breaking the seed plants. In early to mid-August, the seed plants can be harvested for sprouting.

For dry-cultivation seed-saving fields, fertilizer and water should be properly controlled before winter to make the seed plants short and sturdy. In mid-to-late April, pull up the selected seed plants, cut off the aboveground part by 10 cm, and replant them. Generally, both row spacing and plant spacing are about 15 cm. Strengthen fertilizer and water management. In early June, cut off the aboveground part 5 cm above the soil to encourage more seed plants to sprout. After cutting, apply 35 kg of 25% compound fertilizer per mu, or 3000 kg of decomposed human manure and urine plus 10 kg of potassium chloride. Keep the field moist at all times, and pay attention to pest and disease control. In mid-to-late August, they can be pulled up for sprouting.