International Journal of Aquaculture, 2025, Vol.15, No.4, 208-220 http://www.aquapublisher.com/index.php/ija 211 can reach more than 95%. In addition, the medium formula of water chestnut tissue culture was optimized. For example, the addition of 6-BA 1.0 mg/L+NAA 0.5 mg/L on MS was beneficial to bud plexus induction, and IBA 1.0 mg/L promoted rooting (Gao et al., 2015). Using organizational rapid breeding technology, a detoxified seedling breeding system for some new varieties has been established. For example, "Guiti No. 3" is an excellent variant strain obtained by ex vivo culture and mutagenesis of stem tip culture. At present, various places are building a "two-stage seedling cultivation" procedure for water chestnut tissue culture seedlings, that is, test-tube seedlings are first refined in a greenhouse, and then moved to the field to fake planting and cultivate strong seedlings to supply production seedlings. 3.3 Construction of healthy seedling system Healthy seedlings are the basis for high and stable crop yields. In response to the problem of pathogen accumulation during water chestnut breeding, in recent years, major production areas have explored and established a water chestnut healthy seedling breeding system (Lü et al., 2011; Xu, 2011). First, breeding of detoxified seedlings: Detoxified test tube seedlings without viruses and fungal pathogens are prepared by stem tip culture combined with heat treatment and other means. Then cultivate the detoxified seedlings indoors in the isolation net to allow them to grow into intrinsic bulbs. Experiments show that after the cultivation of detoxified water chestnut seedlings, the bulb yield increased by 15%~20%, and the incidence rate was significantly reduced. The second is to classify breeding: adopt the third-level breeding system of "original seed garden-good seed breeding garden-production field". The original seeds are planted with detoxified original seeds and strictly isolate diseases and insects (Zhang et al., 2019); the good seeds are expanded to breed original seeds and promoted to various production bases to achieve the synchronous implementation of good seeds and methods. The third is to improve seed potato treatment: Based on traditional sand storage, seed potato warm soup seed soaking and agent seed soaking technology. Soak the water chestnut seed balls in warm water at 55 ℃ for 10 minutes to kill surface bacteria, and then soak the seeds with broad-spectrum fungicides such as pyrophyllin and Fumeishuang, which can reduce the disease rate of seeds by more than 60%. Some regions have also promoted seed potato germination technology to germinate in warm and humid environments in advance to shorten the growth period in the field and achieve premature maturity. 4 Efficient Cultivation Management and Agronomic Regulation Strategies 4.1 Soil and cultivation environment regulation Water chestnuts are suitable for growing in loam or light clay with deep soil layers and sticky texture to ensure that the bulbs have sufficient expansion space and water supply. In cultivation practice, the following main regulatory measures are used for soil and environment: Deeply plough the fields (25 cm~30 cm) after harvesting each quarter and expose the soil to the sun, break the bottom layer of the plow, improve the soil ventilation and permeability, and eliminate some overwintering pests. Jiang Wen et al. pointed out that loose mud beds are conducive to bulb expansion and stolon elongation, and can increase yield by more than 10%. Crop rotation and fallow: Water chestnuts should not be continuously planted, otherwise the soil-borne diseases will be severe. Practice has proved that 2~3 year rotation with rice and other crops can significantly reduce soil bacteria, and the incidence of water chestnut blight has decreased by about 40% (Santosa et al., 2021). Shallow water irrigation: Water chestnuts like shallow water environments. Generally, they maintain a 3 cm~5 cm water layer after transplanting and raising their roots and growing leaves. Dry the fields appropriately 1~2 times during the middle growth period to control ineffective tillering and promote the formation of tubers. During the bulb enlargement period, the rice fields should be kept moist but not deep irrigated to prevent soil from being deficient in oxygen and causing shepherd's rot. Intermediate-cultivation: Perform intermediate-cultivation and artificial weeding 1~2 times during the tillering period of water chestnuts to loosen the soil, increase soil temperature, and reduce weed nutrient competition. During weeding, centralized treatment can be combined with the removal of diseased plants to reduce the base of disease sources in the field (Zhang et al., 2021). Environmental optimization: Water chestnut bases should choose relatively isolated paddy fields that are conducive to drainage and irrigation, and avoid industrial and mining pollution around them to facilitate the acquisition of green pollution-free products.
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