Breeding System, Crossability Relationships and Isolating Mechanisms in the <i>Solanum nigrum</i> Complex

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

“…Schilling and Heiser (1979), however, suggested that the ability to cross was not a useful taxonomic character in the morelloids. Natural hybrids have also been reported between diploids and polyploids and between polyploids themselves (Henderson 1974; Leslie 1978; Venkateswarlu and Rao 1972), although Edmonds (1977) showed that within ploidy level crossability success was much higher than that between ploidy levels. Hybridisation, followed by backcrossing to parental species and/or polyploidisation, has been thought to explain some of the complex morphological variation found within the group (Stebbins and Paddock 1949; Edmonds 1979a).…”

“…Stone cells mostly absent (Australia, South Pacific and South America), but if present (North America, Mexico, Eurasia and Africa) 2–4(6) per berry, 2–4 larger ones >0.5 mm and two smaller ones <0.5 mm in diameter. Chromosome number: 2n =2x=24 (Tokunaga 1933 [as S. dillenii ]; Nakamura 1937 [as S. photeinocarpum ]; Stebbins and Paddock 1949 [as S. nodiflorum ]; Heiser 1955 under S. nodiflorum ; Baylis 1958 as S. nodiflorum ; Soria and Heiser 1961 [as S. nodiflorum ]; Heiser et al 1965 [as S. nodiflorum ]; Edmonds 1972, 1977, 1982, 1983, 1984a; Venkateswarlu and Rao 1972 [vouchers labelled as S. nigrum S14, S30, S31]; D’Arcy 1974a; Henderson 1974; Tandon 1974; Bhiravamurty 1975 [as S. nodiflorum ]; Randell and Symon 1976; Symon 1981; Ganapathi and Rao 1986a; Symon 1985; Schilling and Andersen 1990; Bukenya 1996; Jacoby and Labuschagne 2006; Moyetta et al 2013; Olet et al 2015). …”

“…General overviews of Black nightshade taxonomy and systematics have been published (Edmonds 1977, 1978, 1979a; Chakrabarti and Sharma 1994), including geographically focused taxonomic treatments for South America (Edmonds 1972), North America (Schilling 1981), Australia (Henderson 1974), Africa (Edmonds and Chweya 1997; Olet 2004; Manoko 2007; Edmonds 2012), Europe (Wessely 1960) and the Indian subcontinent (Schilling and Andersen 1990) and detailed cytological, molecular and morphological studies (Saarisalo-Taubert 1967; Venkateswarlu and Rao 1972; Edmonds 1982, 1983, 1984a; Ganapathi and Rao 1986a, 1986b, 1986c, 1986d, 1987a, 1987b; Nandhini and Paramaguru 2014). These studies have greatly enhanced our understanding of the complex morphological and ploidy level variation present in the group, but much taxonomic work remains within the Morelloids especially in South America, where more than half of the known Morelloid species are found (Barboza et al 2013).…”

The Use of Numerical Methods to Describe Population Differentiation

“…The band patterns obtained from acrylamide-gel electrophoresis of seed protein extracts confirm this. It has already been demonstrated that S. luteum is not an autotetraploid form of 5. americanum (Bhaduri, 1945;Tandon and Rao, 1966a, 1966b-, Venkateswarlu and Rao, 1972. Stfbbins (1950) suggested that S. nigrum probably contained four genomes from nodifiorum ( = americanum) or a species closely related to it, and two from some other diploid species.…”

Hybridization Studies of Five Species of the Solanum Nigrum Complex Found in South Africa and two Cocktail Tomato Cultivars

“…Natural hybrids were also reported at higher ploidy levels, e.g. intra-specific hybrids of the hexaploid S. nigrum (Venkateswarlu & Rao, 1972). Where accession distribution overlaps, natural hybrids were also reported among the S. nigrum complex, despite their different ploidy levels, such as between the hexaploid S. scabrum and the diploid S. americanum (Henderson, 1974).…”