Medicinal Plant Research 2025, Vol.15, No.3, 99-109 http://hortherbpublisher.com/index.php/mpr 107 7 Germplasm Innovation and Breeding Strategy Development 7.1 Core germplasm screening and construction The core germplasm screening of Sapindus is based on the dual evaluation of genetic diversity and agronomic-morphological trait expression. Selection criteria typically include: high genetic variability revealed by EST-SSR or ISSR markers, broad representativeness of population structure, and excellent performance in key economic traits such as saponin content, oil content, and fruit quality (Sun et al., 2019; Liu et al., 2021; 2022). The evaluation indicators cover genetic diversity indices (Nei index, observed heterozygosity etc.), principal component analysis (PCA) based on trait data, and the representativeness of the material in the full diversity spectrum. For instance, a study on 149 Sapindus mukorossi germplasms screened out dominant materials, using 19 agronomic-morphological traits and PCA, highlighting the importance of trait diversity and genetic background in the construction of core germplasms (Liu et al., 2021). A well-designed core germplasm bank should not only cover genotype diversity but also take into account phenotypic trait diversity. In the Sapindus mukorossi study, the core set constructed from 161 germplasms contained 40% of the total genetic variation and included representative materials of all major species and trait types (Liu et al., 2022). Among them, materials with high saponin content or high oil content are given priority for inclusion to ensure their application value in breeding and conservation. The integration of molecular and morphological data ensures that the core germplasm has both broad genetic representativeness and outstanding agronomic value, thereby promoting efficient resource management and directed breeding (Sun et al., 2019; Liu et al., 2021; 2022). 7.2 Trait-oriented breeding strategies The breeding program for high saponin content combines phenotypic screening with marker-assisted selection. Genomic studies have identified selective clearance regions and candidate genes (such as CYP716A, CAMTA, HD-ZIP) related to triterpene saponin biosynthesis, providing molecular targets for the improvement of saponin content (Liu et al., 2025). Dominant materials with natural high saponin levels are often used as donor parents in hybridization schemes, and ISSR/EST-SSR markers related to saponin traits make efficient selection in breeding populations possible (Sun et al., 2019; Liu et al., 2021; 2025). The multi-trait aggregation strategy emphasizes the joint introduction of materials with complementary advantages, like high oil content, high saponin content and excellent fruit quality, into the breeding population. Association analysis and core germplasm strategy are helpful for aggregating ideal alleles, while PCA and cluster analysis can help screen out material, with the best combination of multiple traits (Sun et al., 2019; Liu et al., 2021). This method can help develop cultivated varieties suitable for diverse industrial applications, and take into account potential trade-offs as well, such as the negative correlation between saponins and oil content in some materials (Liu et al., 2021). 7.3 Sustainable utilization of genetic resources The sustainable utilization of germplasm resources requires the combination of in-situ conservation and ex-situ conservation. The core germplasm bank can provide genetic reserves for ex-situ conservation, while in-situ conservation can maintain the evolutionary process and local adaptability (Liu et al., 2021; 2022). The combination of the two ensures that genetic resources can still achieve long-term preservation and availability in the context of climate change and habitat loss (Liu et al., 2021). participatory breeding, which involves the participation of local communities and stakeholders, is conducive to improving the promotion and application effect of improved Sapindus varieties. The application of community-based germplasm sharing and focused identification strategies (like FIGS) can accelerate the discovery and utilization of new alleles on target traits, making breeding programs more inclusive and responsive to local needs (Stenberg and Ortiz, 2020; Sunitha et al., 2023). 8 Concluding Remarks In the distribution area, Sapindus exhibited obvious phenotypic and genotypic diversity. There are significant differences among different populations in economic traits such as oil content, saponin content, fruit size and
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