Genetic diversity of Solanum nigrum cultivated in Kenya

Abstract. Wagio RS, Runo S, Muchugi A. 2019. Genetic diversity of Solanum nigrum cultivated in Kenya. Asian J Agric 2: 63-71. Solanum nigrum L., sometimes known as black nightshade, is a worldwide weed found on arable land, in gardens, and garbage dumps. It has been utilized in the pharmaceutical industry to produce analgesics, ointments, and vasodilators. Using morphological and Simple Sequence Repeats (SSR) markers, this study aimed to assess the genetic diversity of S. nigrum populations growing in specific regions of Kenya. One hundres-twenty (120) samples from four populations were evaluated in total. Morphological characterization utilized four aerial characters. leaf surface (smooth and hairy), leaf margin (whole and sinuous), leaf form (ovate, lanceolate, and diamond), fruit color (red, purple small, and purple large). Tukey's HSD test demonstrated substantial variation among the evaluated attributes (P?0.05). Four SSR primers produced 63 polymorphic bands, ranging from 14 to 17 per primer set. The range of Polymorphic Information Content was 0.1429 to 0.1855, with a mean value of 0.1704. Heterozygosity (using SSR markers) averaged out to be He=0.1370. Axis 1 and 2 of the PCoA explained 44.65% of the population distribution variance. The analysis of multi-level variance (AMOVA) showed that there was only 14% variation between populations and 86% variation inside the populations. Nei's genetic distance varied between 0.010 (Kipkaren and Matanya) and 0.020 (Makuyu and Mauche). Using DARwin 6.0.5 and Unweighted Neighbor Joining with 1000 bootstraps, a dissimilarity study was conducted. The absence of morphological and genetic distinctions in the dendrogram is indicative of the absence of genetic divergence between groups. Variance in the Agro-Ecological Zone is not indicative of variation in the S. nigrum cultivars. Comparing morphological and molecular data revealed leaf surface and fruit color grouping with genetic data. Using the same data, however, there was no grouping between leaf shape and leaf margin. The observed physical distinctions are primarily the effect of human selection. This study demonstrates that the S. nigrum complex displays limited genetic diversity but considerable morphological heterogeneity. Low genetic distance and the absence of clustering patterns indicate that S. nigrum is a closely related group of plants. The results of this study will have far-reaching implications for future breeding efforts of the Solanum complex, as they will be utilized to produce markers connected to crucial agronomic features. The findings will contribute further to resolving the taxonomic ambiguity surrounding S. nigrum.