Rice Genomics and Genetics 2024, Vol.15, No.6, 309-319 http://cropscipublisher.com/index.php/rgg 311 2.3 Conservation of genetic resources The conservation of rice genetic resources is vital for maintaining the genetic diversity necessary for future breeding efforts. Both ex-situ and on-farm conservation methods are employed to preserve these resources. Ex-situ conservation involves storing seeds in genebanks, which helps protect genetic material from loss due to environmental changes or human activities (Wang et al., 2016). However, on-farm conservation, where traditional varieties are maintained by farmers in their natural habitats, plays a crucial role in preserving the dynamic evolutionary processes and maintaining higher genetic diversity (Cui et al., 2019a). Studies have shown that on-farm conservation can lead to greater allelic variation and genetic diversity compared to ex-situ methods, highlighting the importance of integrating both approaches for effective conservation. Additionally, the use of modern genomic tools and databases has facilitated the identification and characterization of novel alleles in wild rice species, further aiding conservation efforts (Kamboj et al., 2020). 3 Contributions of Traditional Varieties 3.1 Agronomic traits of traditional varieties Traditional rice varieties possess a range of agronomic traits that are crucial for breeding programs. These varieties often exhibit unique characteristics such as stress resistance, disease resistance, and specific grain qualities that are highly valued in different regions. For instance, traditional varieties in South China have been shown to have diverse traits related to heading date, plant type, panicle type, grain type, and yield, which have been crucial in the development of high-yielding inbred indica rice varieties (Feng et al., 2023). Additionally, wild rice species like Dongxiang common wild rice exhibit excellent resistance against stress and diseases, providing a rich genetic resource for improving modern rice varieties. 3.2 Cultural and regional significance Traditional rice varieties hold significant cultural and regional importance. They are often preferred by local consumers due to their specific quality attributes, which are deeply embedded in regional culinary traditions. The diversity in consumer preferences for rice quality traits across different regions drives the market and influences breeding strategies. For example, the complexity of rice quality traits and their combinations, as identified in various regions, underscores the importance of aligning breeding programs with local consumer demands to ensure economic success (Calingacion et al., 2014). This cultural and regional specificity is a key factor in the continued cultivation and preservation of traditional rice varieties. 3.3 Challenges in utilizing traditional varieties Despite their valuable traits, utilizing traditional rice varieties in modern breeding programs presents several challenges. One major issue is the reduction in genetic diversity that often accompanies domestication and selective breeding. This can lead to a loss of beneficial traits found in wild and traditional varieties (Li et al., 2022). Additionally, traditional varieties may have agronomic limitations such as lower yield potential compared to modern high-yielding varieties. For instance, while dwarf breeding has increased the yield of inbred indica rice varieties in South China, it has also led to reductions in plant height, flag leaf size, and panicle length, which in turn limit the overall yield potential. Addressing these challenges requires innovative breeding strategies that can integrate the beneficial traits of traditional varieties while overcoming their limitations. 4 Contributions of Wild Varieties 4.1 Unique traits of wild varieties Wild rice varieties, such as Oryza rufipogon and Oryza nivara, possess unique traits that are highly beneficial for rice breeding programs. These wild varieties exhibit disease resistance and drought tolerance, which are critical for developing resilient rice cultivars (Sangeetha et al., 2020). Additionally, wild rice species have adapted to a range of geographical habitats, enriching them with novel traits that can be introgressed into modern cultivated varieties to enhance yield and adaptability. For instance, the wild allotetraploid rice Oryza alta has been identified for its potential in genome buffering, vigorousness, and environmental robustness, making it a valuable resource for de novo domestication (Yu et al., 2021; Zhu et al., 2024).
RkJQdWJsaXNoZXIy MjQ4ODYzNA==