Key Scientific Questions and Recent Advances in Cassava Molecular Breeding

As an important root crop, cassava ( Manihot esculenta Crantz) is not only vital to food security in tropics and subtropics but also the predominant raw material of the starch industry. Ensuring a high and stable yield with better quality is always the main objective of cassava breeders. Nowadays, cassava breeding faces the transition phase from traditional cross-breeding to genetic engineering. Therefore, it is essential to better understand the specific economic traits and biological features of cassava in order to effectively improve the crop through application of biotechnological tools. Unlike cereal crops, the sink/source regulation of photo-assimilate transport and partitioning in cassava must be unique. Moreover, the sink strength of storage root can directly affect cassava yield. As a tropical crop, increasing our understanding of cassava response to low temperature and drought conditions will provide fundamental knowledge to develop useful approaches in its tolerance to abiotic stresses. Post-harvest physiological deterioration (PPD), a unique phenomenon of cassava storage roots being different from other tuberous crops that causes huge production losses, need to be prevented by timely controlling the PPD occurrence in order to extend their shelf life. With the development of molecular biology, study on these issues is drawing more attention to the interested public as well as researchers globally. It is believed that cassava molecular breeding will be greatly promoted by the development of novel approaches derived from intensive basic research of cassava.