Assessment of Morphological Diversity in Cassava (Manihot esculenta Crantz) Core Collection: Insights for Germplasm Conservation and Breeding in Togo

Objectives: Assessing genetic diversity within crop germplasm is essential for effective breeding programs. This study aimed to assess morphological diversity within Togo’s cassava germplasm to guide conservation and breeding efforts. Materials and Methods: The one hundred fourty nine (149) cultivars phenotyped were collected across the country and planted in an augmented block design, with five improved and released varieties used as checks. In total, thirty two (32) qualitative traits were collected based on the cassava crop ontologie. Multivariate analyses of the data collected were run (descriptive analysis, Multiple Correspondance Analysis and Cluster Analysis) using SAS 9.4 and XLSTAT software. Results and implications: Overall, high morphological diversity was observed among the cultivars for all the traits evaluated. The most diverse traits included petiole color, leaf color, leaf vein color, flowering and seed set abilities, branching levels, end branch color, stem epidermis color, lobe margins, and growth habit of stem. Seven morphotypes with interesting features were identified through cluster analysis. Morphotype 1 is made of unflowering and unbranching cultivars with greenish-red petioles. Morphotype 2 is composed of varieties exhibiting purple petioles, three levels of branching, dichotomous branching habit, good flowering and seed set ability. Morphotype 3 made of onlyonecultivar was considered as outlier. Morphotype 4 cultivars are characterized by red petioles, compact plants, white root pulp and bad seed set hability; whereas cultivars belonging to morphotype 5 exhibited green petiole, good flowering and seed set abilities. Morphotype 6 is made of cultivars with sessile peduncle root, conical cylindrical root, orange root pulp, short distance between leaf scars, good flowering and seed set ability. Morphotype 7 genotypes exhibited dark green apical leaves, cream stem epidermis, two levels of branching, good flowering and seed set ability. The most diverse traits identified in this study could be used for genetic resources identification. Parent cultivars could be selected from morphotypes harbouring good flowering and seed set habilities.