Unveiling genetic diversity in jute mallow (Corchorus spp.): morphological clustering reveals distinctive traits among accessions from Africa and Asia

Jute mallow is an important crop produced for its leaves and fiber. In Africa, it is mostly produced and consumed as a leafy green vegetable. We evaluated thirty-two qualitative and quantitative morphological traits at two locations to assess the genetic diversity among two hundred and eighty-three accessions of Corchorus olitorius var. olitorius, Corchorus olitorius var. incisifolius Asch. & Schweinf., and Corchorus capsularis L. mostly from West Africa and additional samples from East Africa, Asia, and other regions. High morphological diversity was detected in the accessions evaluated. The main distinctive morphological traits of the accessions were leaf shape, the leaf margin, the plant growth habit and the number of primary branches. Multivariate analysis grouped the accessions into four clusters (referred to as Cluster 1: “Seed yield”, Cluster 2: “Intermediate”, Cluster 3: “Capsularis” and Cluster 4: “Leaf yield”), which are named after the key characteristics that defined them. The Corchorus capsularis accessions were clustered together and separated from the C. olitorius L. accessions. However, within the latter species, the analysis revealed further separation into two groups irrespective of the subspecies: one with fewer primary branches and a greater leaf surface area than the other with a greater number of primary branches and smaller leaves. Leaf surface area, days to 50% flowering, days to 90% pod maturity and the number of primary branches were important traits that contributed to a high harvest index and hence a high fresh leaf yield. The findings in the current study can help focus and accelerate breeding programs targeting important traits, including leaf shape, branching, flowering time, and leaf and seed yields.