Genetic diversity of the African hexaploid species Solanum scabrum Mill. and Solanum nigrum L. (Solanaceae)

Abstract

Two hexaploid species of Solanum sect. Solanum are present in Africa: Solanum scabrum and S. nigrum. Solanum scabrum is a widely cultivated species and is used as a leafy vegetable, as a source of medicine and as a source of ink dye. In previous studies a wide range of morphological diversity has been reported in this species and in some studies subspecies have been proposed. Subspecies are also recognized in S. nigrum. However, it has not been established whether or not the morphological differences are reflected at the genomic level. The present study applies AFLPs to study the genetic diversity in S. scabrum and its relationship to geographical provenance, morphological differences and the possible existence of subspecies within S. scabrum and S. nigrum. The data obtained were analyzed with cluster analysis (using UPGMA and NJ). The results indicate that the genetic variation within S. scabrum was higher within accessions than between accessions. Accessions did not cluster according to their geographical provenance, indicating that accessions from different geographical areas were not significantly different genetically. The clustering reflected neither morphological differences nor domestication status (cultivated or wild). The morphological differences exhibited by S. scabrum could be due to selection by farmers for different plant types. The AFLP derived clustering pattern did not segregate the subspecies recognized in S. scabrum and S. nigrum into separate subclusters.

A revision of the Old World Black Nightshades (Morelloid clade of Solanum L., Solanaceae)

“…Results from seed protein studies (Edmonds and Glidewell 1977), as well as from more recent population genetic studies (e.g. Manoko 2007; Manoko et al 2008) support our morphological observations in finding no obvious patterns supporting infraspecific structure within particular variable species such as S. americanum , S. villosum and S. nigrum .…”

“…Manoko (2007; Manoko et al 2008) showed that this character did not correspond to monophyletic groups in his AFLP analyses of S. nigrum or S. villosum . Several species amongst the Old World black nightshades have both glandular and eglandular populations and individuals (e.g.…”

Study of the origin of the rarely cultivated edible Solanum species: morphological and molecular data

“…Although, the morphology of cultivated species is different from its wild ancestor and displays much greater diversity, in isozyme, DNA or other molecular markers the diversity remains almost the same (Lester and Daunay 2003). It can be concluded that hair characteristics have low taxonomic value at the subspecies level in section Solanum, confirming the results of Manoko et al (2008), Dehmer (2001) and Dehmer and Hammer (2004). The present study shows that S. nigrum, S. scabrum are closely related species, although this is supported by only moderate bootstrap value, it confirms our previous conclusions (Poczai et al 2008).…”

“…These differences could be attributed to breeding selection for different plant types. S. scabrum is the most intensively cultivated leafy vegetable in section Solanum, and as such has undergone selection by farmers (Manoko et al 2008). Presumably in this case, leaf size, stem wing and stem branching characters were the basis for selection.…”

Preliminary assessment of COSII gene diversity in lulo and a relative species: Initial identification of genes potentially associated with domestication

“…Among the Solanaceae, the monophyletic genus Solanum is the largest and most diverse one, with 1000 to 2000 species growing in all habitats from rainforest to deserts (Bohs, 2007;Bohs and Olmstead, 1999;Chung et al, 2006;Heiser and Anderson, 1999;Manoko et al, 2008). Species belonging to the Solanum genus show a remarkable agronomic importance, some of them are a basic part of diets in different parts of the world (i.e.…”