Genetic characterisation of solanum nigrum and related species using simple sequence repeats
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Date
2014-10-08
Authors
Rwigi, Susan Wagio
Journal Title
Journal ISSN
Volume Title
Publisher
Kenyatta University
Abstract
Solanum nigrum (commonly referred to as black nightshade) and related species are
world-wide weeds on arable land, gardens, rubbish pits, soil rich in nitrogen in
moderately light and warm situation which occur from sea to montare levels. Human
consumption of leaves and fruits as food is wide spread, particularly in Africa and South
East Asia. Nightshades have also been used in the field of medicine in the manufacture
of analgesics, ointments and vasodilators. In Kenya there are three distinct varieties of
black nightshade, grown in high, medium and low altitude areas. Broad leafed
nightshades are found throughout Africa. There are several wild species but the most
popular species is Solanum scabrum. A wild variety Solanum villosum has also been
identified in a number of regions in Kenya. Solanum nigrum and related varieties can be
grown in wide range of soil types but do not tolerate drought. Yields range from 20-40
tons per hectare under good management. Many of the species are poisonous giving
varying degree of toxicity which may be mildly irritable to causing fatalities with small
quantities. In Kenya these species are found extensively around Mt Kenya, Mau forest,
Kisii highlands and Kakamega. Farming is not extensive and only few farmers produce
the crop. The limited information available on importance and basic aspects of this
neglected and underutilized family, such as black nightshade, hinders the development
of these species as well as their sustainable conservation. Exisisting knowledge on the
genetic potential of these plants are limited and the information regarding the genomic
organization of Solanum nigrum complex species found in Kenya is scarce. However
molecular markers could help us gain a better understanding and the information could
improve the genetic analysis to facilitate future breeding programmes. This work targets
the use of SSR molecular markers in determining the genetic diversity of both cultivated
and wild varieties of black nightshades in selected parts of Kenya. Leaf samples will be
collected from five regions and morphological analysis done on leaf shape, colour of the
fruits, nature of leaf surface and type of leaf margin. Samples will then be dried in snaptop
bag containing silica gel in readiness for DNA extraction using the CTAB protocol.
A set of7 SSR primers as used by Angeline van Biljon et ai, 2010 will be used for PCR
amplification of the DNA. Final DNA concentration will be confirmed by
electrophoresis in 2% agarose gel run at 120v for 40min in a TAE (tris acetate
ethlydiquine tetra acetic acid) buffer and visualized with ethidium bromide staining
under UY light. Bands in the SSR profiles of each individual plant will be scored as
present or absent (lor 0, respectively) and subjected to sequential clustering algorithm
using the Unweighted Pairgroup method with Arithmetic Means (UPGMA).The lengths
will be analysed in an automated ABIR31 0 sequencer (Applied Biosystem) that use gene
mapper TMsoftware. Morphological data will be subjected to analysis of variance
(ANOY A) by the GLM procedure of the Statistical Analysis System and correlation
coefficient to determine the degree of diversity. The relationships within populations of
cultivated and wild types will be generated using phylogenetic analysis package
GenAlex 6.3.and presented in a dendogram. Findings from this study will be useful in
the improvement of wild black nightshade germplasm to develop suitable plants using
Marker Assisted Selection