Breeding systems in some representatives of the genus &lt;i&gt;Lycium&lt;/i&gt; (Solanaceae)

L, Minne; Spies, J. J.; Venter, H.J.T.; Venter, A.M.

doi:10.4102/abc.v24i1.759

Cited by 22 publications

(17 citation statements)

References 4 publications

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“…However, as is common in other gynodioecious species (e.g., Puterbaugh, Wied, andGalen, 1997, reviewed in Eckhart, 1999), there are several morphological correlates associated with male sterility in Lycium, such as shorter corolla tubes and more narrow corolla diameters (Miller and Venable, in press). Polyploid, dimorphic species of Lycium in southern Africa also show no evidence for agamospermy (Minne et al, 1994). We found no evidence for autogamous self-pollination in hermaphrodites and little evidence for agamospermy in females for any of the polyploid dimorphic species.…”

Section: Male Sterility Stability Of Gender Expression and Sex Raticontrasting

confidence: 61%

“…For all three dimorphic species, hermaphrodites have larger ovaries than those on conspecific females and ovule number does not differ between females and hermaphrodites for any of the dimorphic species (J. S. Miller, unpublished data). For example, in African dimorphic Lycium, hermaphrodite plants of the functionally dimorphic species sometimes have completely vestigial styles and stigmas, but otherwise intact ovaries (Minne et al, 1994). It is possible that the disproportionately shorter style and smaller stigma of hermaphrodites (compared to females; Miller and Venable, in press) is an early manifestation of specialization of hermaphrodites towards male function.…”

Section: Male Sterility Stability Of Gender Expression and Sex Ratimentioning

confidence: 99%

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The transition to gender dimorphism on an evolutionary background of self‐incompatibility: an example from Lycium (Solanaceae)

Miller

Venable

2002

American J of Botany

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Populations of three North American species of Lycium (Solanaceae) are morphologically gynodioecious and consist of male-sterile (i.e., female) and hermaphroditic plants. Marked individuals were consistent in sexual expression across years and male sterility was present throughout much of the species' ranges. Controlled pollinations reveal that L. californicum, L. exsertum, and L. fremontii are functionally dioecious. Fruit production in females ranged from 36 to 63%, whereas hermaphrodites functioned essentially as males. Though hermaphrodites were mostly male, investigation of pollen tube growth reveals that hermaphrodites of all dimorphic species were self-compatible. Self-fertilization and consequent inbreeding depression are commonly invoked as important selective forces promoting the invasion of male-sterile mutants into cosexual populations. A corollary prediction of these models is that gender dimorphism evolves from self-compatible ancestors. However, fruit production, seed production, and pollen tube number following outcross pollination were significantly higher than following self-pollination for three diploid, cosexual species that are closely related to the dimorphic species. The data presented here on incompatibility systems are consistent with the hypothesis that polyploidy disrupted the self-incompatibility system in the gynodioecious species leading to the evolution of gender dimorphism.

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Section: Male Sterility Stability Of Gender Expression and Sex Raticontrasting

confidence: 61%

Section: Male Sterility Stability Of Gender Expression and Sex Ratimentioning

confidence: 99%

The transition to gender dimorphism on an evolutionary background of self‐incompatibility: an example from Lycium (Solanaceae)

Miller

Venable

2002

American J of Botany

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“…Polyploidy is known in several Lycium species from all over the world; the most common polyploid levels are 4x, 6x, and 8x, whereas 3x and 10x are rarely observed (FEDOROV 1969;BER-NARDELLO 1982;CHIANG-CABRERA 1982;VENTER 2000). Polyploidy in Lycium is most common in southern Africa, where approximately 30% (7 of 24 species) of its species are polyploids (SPIES et al 1993;MINNE et al 1994;VENTER 2000;2007). In contrast, polyploidy is considerably less common (7 of 51 species) in American Lycium (LEWIS 1961;BAQUAR et al 1965;CHIANG-CABRE-RA 1982;BERNARDELLO 1982;BER-NARDELLO 2000, 2006 (2000) hypothesized both auto-and allopolyploid origins for several African polyploids.…”

Section: Discussionmentioning

confidence: 99%

Karyotypes and ﬂuorescent chromosome banding patterns in southern AfricanLycium(Solanaceae)

et al. 2010

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-Chromosomal analyses of several southern African Lycium species resulted in diploid (2n=24: L. amoenum, L. bosciifolium, L. ferocissimum, L. oxycarpum, L. tenue), tetraploid (2n=48: L. gariepense, L. strandveldense, L. hantamense), and hexaploid (2n=72: L. tetrandrum) counts. Chromosomes in all species were short (mean length = 2.00 μm; mean haploid genome length = 23.77 μm). Further, all species shared a highly symmetrical karyotype formula with 10 m pairs and 2 sm pairs, except L. bosciifolium with only one sm pair. The fi rst m pair had a terminal microsatellite on the short arms. Fluorescent chromosome banding patterns with CMA/ DAPI staining in the diploid species showed NOR-associated heterochromatin in the fi rst satellited pair. The tetraploids L. gariepense and L. hantamense had two chromosome pairs with a CMA + /DAPI -terminal band. Phylogenetic studies have shown that the southern African species are included in a monophyletic group including all Old World Lycium; these species are likely of recent origin and, despite ploidy differences, karyotypes are remarkably similar among species. Available data for South American, Asian, and southern African Lycium indicate that there is a common pattern of mostly m chromosomes in which a few cryptic chromosomal rearrangements may have occurred, suggesting that karyotypic orthoselection has preserved similar patterns among species. Thus, these data imply that speciation in Lycium was not accompanied by changes in chromosomal morphology.

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“…Most Lycium species have perfect flowers on all plants and are cosexual in gender expression (Hitchcock 1932;Chiang-Ca-brera 1981;Bernardello 1986). However, six of the 17 species occurring in Africa have been described as functionally dioecious (Minne et al 1994;Venter et al 1999). None of the 30 South American species are dimorphic in gender expression (Bernardello 1986).…”

Section: Study Speciesmentioning

confidence: 99%

Floral Morphometrics and the Evolution of Sexual Dimorphism in Lycium (Solanaceae)

Miller

Venable

2003

Evolution

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Plants of Lycium californicum, L. exsertum, and L. fremontii produce flowers that are either male-sterile (female) or hermaphroditic, and populations are morphologically gynodioecious. As is commonly found in gynodioecious species, flowers on female plants are smaller than those on hermaphrodites for a number of floral traits. Floral size dimorphism has often been hypothesized to be the result of either a reduction in female flower size that allows reallocation to greater fruit and seed production, or an increase in hermaphroditic flower size due to the increased importance of pollinator attraction and pollen export for hermaphroditic flowers. We provide a test of these two alternatives by measuring 11 floral characters in eight species of Lycium and using a phylogeny to reconstruct the floral size shifts associated with the evolution of gender dimorphism. Our analyses suggest that female flowers are reduced in size relative to the ancestral condition, whereas flowers on hermaphrodites have changed only slightly in size. Female and hermaphroditic flowers have also diverged both from one another and from ancestral cosexual species in several shape characteristics. We expected sexual dimorphism to be similar among the three dimorphic taxa, as gender dimorphism evolved only a single time in the ancestor of the American dimorphic lineage. While the floral sexual dimorphism is broadly similar among the three dimorphic species, there are some species-specific differences. For example, L. exsertum has the greatest floral size dimorphism, whereas L. fremontii had the greatest size-independent dimorphism in pistil characters. To determine the degree to which phylogenetic uncertainty affected reconstruction of ancestral character states, we performed a sensitivity analysis by reconstructing ancestral character states on alternative topologies. We argue that investigations such as this one, that examine floral evolution from an explicitly phylogenetic perspective, provide new insights into the study of the evolution of floral sexual dimorphism.

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Breeding systems in some representatives of the genus <i>Lycium</i> (Solanaceae)

Cited by 22 publications

References 4 publications

The transition to gender dimorphism on an evolutionary background of self‐incompatibility: an example from Lycium (Solanaceae)

The transition to gender dimorphism on an evolutionary background of self‐incompatibility: an example from Lycium (Solanaceae)

Karyotypes and ﬂuorescent chromosome banding patterns in southern AfricanLycium(Solanaceae)

Floral Morphometrics and the Evolution of Sexual Dimorphism in Lycium (Solanaceae)

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