Morphotype-based characterization of tomato (Solanum lycopersicum L.) accessions cultivated in Togo for conservation and genetic improvement

Introduction Tomato ( Solanum lycopersicum L.) is one of the most important vegetable crops worldwide, yet its production is constrained by limited knowledge of locally cultivated varieties. Breeding of high-performing varieties requires a clear understanding of available genetic resources. This study aimed to characterize tomato accessions cultivated in Togo based on morphotype variation, with implications for conservation and genetic improvement. Methods A total of forty-five (45) accessions collected across the country were phenotyped under field conditions at the Coastal Agricultural Research Center (CRAL/Davié) station using a randomized complete block design with three replications. A total of eleven morphological traits were recorded according to the tomato crop ontology. Descriptive statistics, multiple correspondence analysis (MCA), and cluster analysis were carried out to assess the germplasm diversity and its structure. Results and discussion MCA revealed substantial variability among accessions in plant size, vigor, stem pubescence, foliage density, leaf shape, and severity of Tomato Yellow Leaf Curl Virus (TYLCV) and bacterial wilt. Field evaluation under natural infection conditions indicated that several accessions exhibited tolerance to bacterial wilt (91%) and TYLCV (76%), underscoring their value for genetic improvement programs. Cluster analysis revealed five distinct morphotypes, highlighting considerable diversity among the accessions. Morphotype 1 (6 accessions) comprised large, vigorous genotypes susceptible to TYLCV but tolerant to bacterial wilt, whereas morphotype 2 (18 accessions) included intermediate, vigorous genotypes with the inverse response. Morphotype 3 was represented by a single, distinct accession exhibiting tolerance to bacterial wilt. In contrast, morphotypes 4 (13 accessions) and 5 (7 accessions) grouped short-statured genotypes exhibiting dual field tolerance, differing in plant vigor and leaf architecture. The identified polymorphic traits constitute robust phenotypic descriptors for preliminary varietal identification and offer practical entry points for targeted breeding strategies. Collectively, this germplasm provides a valuable genetic reservoir for the development of high-yielding, resilient tomato cultivars adapted to local agro-ecological conditions, with significant implications for enhancing food and nutritional security in Togo.