Most of the cassava varieties cultivated in my country are imported from abroad, and a few are domestically selected.
Germplasm resources are the material basis for crop breeding. Therefore, extensive collection, proper preservation, active innovation and full utilization can provide diverse parents for cassava breeding and promote cassava variety improvement.
There are currently more than 8,500 cassava germplasm (including wild cassava germplasm) collected and preserved in cassava producing areas around the world, mainly distributed in more than 40 countries including Brazil, Colombia, Nigeria, India, Indonesia and Thailand. Among them, the International Center for Tropical Agriculture (CIAT) has established an international cassava germplasm nursery, collecting and preserving more than 6,000 cassava germplasms. It has also conducted research on the storage characteristics of cassava, and successfully used tissue culture technology to induce sterile test tube seedlings for indoor storage. , can be stored for 18 to 24 months under good conditions, which greatly saves the land and labor intensity of field preservation and avoids the risk of germplasm loss. Recent research shows that cassava seeds can be stored for a long time under low temperature and low humidity conditions. However, when seeds are preserved and their offspring are separated, what is preserved is not the genotype of the original species, but the separated genotype. Therefore, to preserve the original genes, an appropriate amount of seeds must be collected from multiple mother plants in the natural population. Otherwise, genetic transfer will occur, resulting in gene loss.
The research on cassava germplasm resources in my country and other Asian countries is not as extensive and in-depth as that of the International Center for Tropical Agriculture and India. In particular, the collection, preservation and utilization of cassava germplasm resources in my country started late and has a poor foundation. During the Seventh Five-Year Plan period, the South China Tropical Crops Research Institute began this work and made some progress. Through the investigation of domestic cassava germplasm resources, a batch of domestic cassava germplasm resources have been collected. At the same time, some excellent foreign germplasm have been introduced from foreign research institutions such as the International Center for Tropical Agriculture. So far, our country has established a research institute at the Chinese Academy of Tropical Agricultural Sciences. The only living nursery of cassava germplasm resources has preserved more than 200 collected and innovative germplasms. At the same time, the agronomic, quality, cold resistance and other traits of some germplasms have been identified and evaluated, a germplasm card file has been established, and the process has begun. Preliminary research on the affinity and combining ability between some germplasms has been carried out and preliminary results have been obtained. However, compared with scientific research institutions such as the International Center for Tropical Agriculture, there are still large differences and must continue to be strengthened.