Molecular Soil Biology 2025, Vol.16, No.2, 73-82 http://bioscipublisher.com/index.php/msb 77 coefficient integrates multiple indicators to provide a comprehensive assessment of disease resistance. These quantitative indicators help to screen out germplasms with strong resistance to a variety of diseases (moparthi et al., 2017). 4.3 Molecular marker assisted screening The genetic diversity of disease resistant germplasms was analyzed by molecular marker technology (including SSR and SNP markers). These markers reveal the polymorphism among germplasms and help identify germplasms with genetic characteristics related to disease resistance (Gu et al., 2010). Candidate genes related to disease resistance were screened by marker trait association analysis. These studies linked specific genetic markers with observed disease resistance traits, and located loci related to resistance to specific diseases such as powdery mildew. This information provides support for the selection of good germplasm in breeding projects (Sun et al., 2022). 4.4 Screening results and determination of excellent germplasm According to the results of phenotype and molecular markers, the germplasms with excellent disease resistance and comprehensive agronomic traits were identified. Selection criteria include low disease index, high disease resistance coefficient and excellent growth performance under stress conditions. An excellent germplasm named "HJ-23" showed excellent resistance to powdery mildew, gray mold and leaf spot in field and artificial inoculation experiments. Molecular analysis showed that it carried alleles of key gene loci related to resistance, and these genes involved in defense signaling pathways (such as MYB transcription factor). HJ-23 also showed high biomass yield and stable motherwort alkali content, making it a strong candidate germplasm for Off-season Cultivation (Sun et al., 2022). 5 Application of Disease-Resistant Germplasm in Off-Season Cultivation 5.1 Seedling production and transplanting techniques Optimizing seedling production and transplanting is key to fully using disease-resistant germplasm. In greenhouses, seedlings should be grown under controlled conditions to reduce early exposure to pathogens. Practices include disinfecting seedling trays, using sterile substrate, and maintaining optimal germination temperatures (20 ℃~25 ℃) and humidity below 70%. These measures improve survival rates and seedling vigor. In open-field cultivation, resistant germplasm should be planted in well-drained soil with added organic matter to support root development (Sun et al., 2022). Transplanting time is as important as management. Disease resistant seedlings should be transplanted in a period with mild environmental conditions to avoid extreme humidity or temperature changes. Reasonable plant spacing (usually 30 cm × 20 cm) helps to reduce the spread of pathogens and ensure good ventilation. Inoculating seedlings with beneficial microorganisms (such as Trichoderma spp.) before transplanting can enhance disease resistance and promote root growth in the field (moparthi et al., 2017). 5.2 Disease management strategies Combining disease resistant germplasm with precise control strategies can significantly enhance the effect of disease management in off-season cultivation. Physical prevention and control measures, such as greenhouse ventilation, humidity regulation and continuous monitoring of microclimate conditions, play a key role in inhibiting the spread of pathogens. Controlling the greenhouse humidity below 60% can effectively inhibit the spread of powdery mildew and downy mildew, which are most likely to breed in high humidity environment (Liang et al., 2018). Biological control measures are complementary to disease resistant germplasms by using biological pesticides and antagonistic microorganisms to inhibit disease outbreaks (Carolan et al., 2017). Beneficial microorganisms such as Bacillus subtilis and Pseudomonas fluorescens inhibit fungal pathogens through competitive rejection and the production of antibacterial compounds. Biopesticides derived from Beauveria bassiana and neem oil provide eco-friendly solutions that can effectively manage fungal and bacterial infections while ensuring plant safety (Gu
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