Abstract

Use of morphological markers offers an alternative in germplasm discrimination of research-neglected crop species. A collection of 25 accessions including five wild progenitors was evaluated in screen house to identify the morphological difference between Solanum aethiopicum Shum and Solanum anguivi. An Unweighted Pair Group Method with Arithmetic mean hierarchical clustering revealed presence of moderate structure with a cophenetic correlation coefficient of 0.73. Five distinct clusters were produced; the progenitor accessions for the S. aethiopicum Shum were grouped in their own cluster. The Richness, Shannon-Weaver and Simpson indices were also different among qualitative variable categories. A ‘prcomp’ function based Principal component analysis (PCA) in R on quantitative variables indicated that days to germination and emergence, cotyledonous leaf length, cotyledonous leaf width, shoot biomass, plant height, petiole length, days to first flowering opening, plant width, plant branching, and number of leaves per plant are the major drivers of variability in the study accessions. Further, results from canonical discriminant analysis to discern between the S. aethiopicum and its progenitor accession groups showed that the days to germination and emergence provide the best separation; with the former emerging earlier than the latter. The mean values for flowering time, leaves per plant, number of branches per plant and plant height were more favorable for the Shum than its wild progenitor accessions. The study revealed that morphological markers are useful in distinguishing between the S. aethiopicum Shum and its progenitor accessions.

Key words: African indigenous vegetable species, genetic diversity, reordered hierarchical clustering, Principal component analysis (PCA), linear discriminant analysis.