Unveiling Cassava Diversity: Agronomic and SNP Marker Trait Profiling in the Democratic Republic of Congo

Abstract

Cassava is a perennial crop known for its adaptability to diverse agro-ecological conditions. In many tropical countries, including the Democratic Republic of Congo (DRC), it is a key contributor to food security, making it the most important staple food. Nearly 90% of cassava roots and leaves harvested in the DRC are consumed by humans, contributing significantly to the population's energy, protein, and micronutrient intake. This study evaluated 136 cassava varieties, including nine improved varieties developed by IITA and INERA-DRC along with 120 local varieties collected from various agro-ecological zones and maintained by INERA. Conducted at INERA Mvuazi in Kongo Central, DRC, the trial used an alpha lattice design with eight blocks and 17 plots replicated twice. Key agronomic traits such as CMD, plant height, biomass, harvest index, dry matter content, starch, and fresh root yield were profiled. Significant phenotypic variation was observed, particularly in plant height (2727.79cm), biomass (55.05kg), and yield (44.24t/ha), with high heritability estimates for traits like starch content (0.55) and biomass (0.98). Hierarchical clustering identified five distinct groups with varying traits and performance, highlighting the diversity within the germplasm. Genotypic analysis using SNP markers revealed substantial genetic diversity, with population structure analysis identifying four genetic clusters. The integration of phenotypic and genotypic data provided a comprehensive understanding of the relationships within the germplasm. The study identified 47 top-ranking cassava varieties with exceptional multi-trait performance, suitable for breeding programs aimed at improving yield, disease resistance, and dry matter content. This research offers valuable insights into the genetic and phenotypic diversity of cassava germplasm in the DRC, supporting future breeding efforts.