Plant Gene and Trait 2025, Vol.16, No.5, 206-214 http://genbreedpublisher.com/index.php/pgt 208 Phyllostachys edulis also has a well-developed underground rhizome system, which can efficiently store and transport nutrients. Studies have found that the carbon distribution of newly rooted rhizomes accounts for 9.5% of the total biomass, which is much higher than that of woody plants of the same size (Kobayashi et al., 2022). It has a strong adaptability to NH4 + in nitrogen fertilizers and performs better and has stronger competitiveness in a high ammonia environment (Zou et al., 2020; Hong et al., 2024). In addition, Phyllostachys edulis can improve soil water retention and increase microbial diversity by regulating rhizosphere microorganisms and soil properties, thereby enhancing the stability of the ecosystem (Liu et al., 2023; Fang et al., 2024). 2.2 Economic value of bamboo shoots as food Bamboo shoots are important cash crops. They grow fast, have high yields and are rich in nutrients. Bamboo shoots contain protein, amino acids, dietary fiber and various trace elements, and are excellent raw materials for healthy food. Bamboo shoots can not only meet the demands of domestic and foreign markets, but also promote the development of the food processing industry, becoming an important support for increasing farmers' income and regional economy. Some new varieties, such as Phyllostachys edulis ‘Pachyloen’, not only have high yields but also good edible quality, further enhancing economic value (Hu et al., 2020). 2.3 Timber properties and industrial applications The mechanical properties of Phyllostachys edulis timber are excellent, with high strength, light weight and good toughness. It is widely used in industries such as construction, furniture, papermaking and textile (Hu et al., 2020). The cellulose and lignin content of Phyllostachys edulis is also very high, making it suitable for the production of high-performance composite materials and biomass energy (Chen et al., 2022). The formation of Phyllostachys edulis timber is also regulated by hormones. For instance, gibberellin treatment can promote internode elongation and lignin deposition, thereby enhancing the mechanical properties of timber (Zhang et al., 2018). Due to its large biomass and fast carbon cycle, Phyllostachys edulis also has great application potential in carbon sinks and ecological restoration (Hu et al., 2020; Kobayashi et al., 2022). 3 Traditional Breeding Approaches 3.1 Selection of elite germplasm for shoots and timber The selection of superior germplasm is at the core of traditional bamboo breeding. Phyllostachys edulis is widely cultivated because of its high yield of shoots and good quality of timber. Researchers usually select outstanding individual plants or groups by conducting phenotypic observations on natural populations and artificial forests, such as growth rate, bamboo shoot yield, and timber strength, as the basis for production and subsequent breeding. In recent years, the application of whole-genome resequencing and molecular markers has provided genetic data support for these superior traits. These tools help to identify candidate genes related to important traits such as timber mechanical properties, thereby improving germplasm utilization efficiency (Del Giudice et al., 2022). 3.2 Vegetative propagation and clonal breeding It is rare for Phyllostachys edulis to flower and bear fruit, and its generation cycle is very long (generally 60 to 120 years), so asexual reproduction has become the main method of propagation and breeding. Phyllostachys edulis mainly expands through underground whip roots and can form large-scale clonal colonies. Studies have found that most of Phyllostachys edulis forests in East Asia almost all originated from the same clonal line, and human transplanting and natural expansion jointly created an extremely large single clonal population (Isagi et al., 2015). In addition, tissue culture and cuttings have also been used to rapidly propagate superior strains and ensure the stable transfer of traits (Isagi et al., 2015; Huang et al., 2022a). However, long-term reliance on asexual reproduction has led to very low genetic diversity of Phyllostachys edulis, which also increases its risk when facing pests, diseases and environmental stress (Isagi et al., 2015). 3.3 Hybridization attempts and limitations in bamboo breeding The hybrid breeding of Phyllostachys edulis is very difficult. The biggest problem is that its flowering habit is extremely irregular and its seeds are very difficult to obtain (Gao, 2021). Even if it flowers occasionally, the number of seeds is small, the germination rate is low, and the seedlings have difficulty competing with mature bamboo or other tree species in the natural environment. Therefore, it is difficult to form a new dominant
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