Chapter 11 - Variation in cassava landraces: high levels of diversity in germplasm from central Brazil

Abstract

Cassava is one of the major tuber crops. Its roots are an important source of commercial starch and staple food for many tropical countries. Observations in its center of origin (central Brazil) showed that local producers maintain a wide range of phenotypic diversity, especially at root morphology. To quantify this variation and its distribution, we performed a morphologic characterization coupled with a genotyping approach to assess genetic relatedness and diversity and to unravel potential signatures of admixture. Our genetics analysis revealed that 40% of the sampled individuals showed patterns of genetic admixture, indicating that cross-pollination and seed propagation may play an important role in the propagation and diversification of the crop. Our study revealed high levels of phenotypic and genome-wide diversity and highlights the potential importance of traditional practices in the generation, conservation, and maintenance of genetic diversity. Several of these varieties/landraces have the potential for breeding purposes and should be included in programs that aim for the conservation of plant genetic resources.