Cassava breeding: Classical to recent breeding approaches for food, industry and climate resilience

Cassava ranks as the fourth-most significant starchy root crop in underdeveloped countries in terms of future food and acting as a key source of income for small and marginal farmers. To meet the growing demands for food security and economic development, it is imperative to develop improved cassava varieties that offer higher yields, enhanced nutritional content, safer for consumption, greater resistance to diseases and climate change. The development of these improved varieties necessitates advancements in breeding techniques, leveraging both traditional methods and modern biotechnological tools. However, a major challenge in cassava breeding is heterozygous nature and the crop’s sparse flowering, which limits the potential for sexual reproduction, thereby constraining breeding efforts for predominantly clonal selection. The continuous clonal propagation impedes genetic diversity and the introduction of novel traits, narrowing the overall progress of breeding programs. Integrating genomic tools and accelerating the adoption of biotechnological advancements can overcome these limitations and expedite the development of superior cassava varieties. This review highlights the need of cassava breeding for addressing these challenges with conventional as well as with new breeding techniques with the aim to provide a comprehensive understanding of the current scenario and future directions of cassava breeding research. Key words: Climate change, CRISPR/Cas 9, New breeding techniques, PPD, speed breeding, Waxy cassava