Evolutionary patterns in the Dilatata group (Paspalum, Poaceae)

Speranza, Pablo

doi:10.1007/s00606-009-0205-5

Cited by 22 publications

(24 citation statements)

References 48 publications

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“…A different genetic system occurs in P. dilatatum in which allopolyploidy at tetraploid level is also associated with sexual reproduction but conspecific allopentaploid and allohexaploid apomictic races also exist (Burson 1983). Moreover, several biotypes of each ploidy level of P. dilatatum were recognized by its morphology, cytology and reproductive behaviour (Burson 1983(Burson , 1995 and also by molecular methods (Speranza 2005;Speranza and Malosetti 2007;Miz and Souza-Chies 2006 and references therein). Paspalum ionanthum Chase resulted also tetraploid (2n = 4x = 40), however it is an exceptional species because have sexual cross-pollinated tetraploids and also co-specific apomictic octoploids instead most of 4x of Paspalum are autogamous (sub P. guaraniticum Parodi, Burson and Bennett 1970;Quarin and Norrmann 1987b).…”

Section: Tetraploidsmentioning

confidence: 99%

Chromosome numbers and ploidy levels of Paspalum species from subtropical South America (Poaceae)

Hojsgaard

Honfi

Rua

et al. 2008

Genet Resour Crop Evol

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Somatic chromosome numbers of 131 accessions belonging to 55 Paspalum species from subtropical South America have been determined. All species had x = 10 as a basic chromosome number, except P. almum which had x = 6. Six ploidy levels were found among species with tetraploidy as the most frequent condition. New diploid and octoploid counts were reported. For Paspalum lilloi and P. glabrinode (both 2n = 2x = 20), and for P. ellipticum, P. erianthoides, P. ovale and P. remotum (all 2n = 8x = 80) sporophytic chromosome numbers are presented for the first time. Records that differ from previously reported counts are given for the following species: P. paucifolium (2n = 2x = 20), P. ceresia (2n = 6x = 60), P. conjugatum (2n = 6x = 60), P. alcalinum (2n = 6x = 60) and P. aff. arundinellum (2n ? 1 = 5x ? 1 = 51). These chromosome data are discussed in light of ploidy-level variation and implications for breeding systems within and among species.

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Section: Tetraploidsmentioning

confidence: 99%

Chromosome numbers and ploidy levels of Paspalum species from subtropical South America (Poaceae)

Hojsgaard

Honfi

Rua

et al. 2008

Genet Resour Crop Evol

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“…Seven genotypes of P. dilatatum, representing part of the natural genetic variability described by Speranza (2009), were evaluated for germination behaviour. These genotypes included four pentaploid apomictic clones of P. dilatatum subsp.…”

Section: Plant Material Seed Harvest and Dry Storage Conditionsmentioning

confidence: 99%

“…Similar limitations have been reported in several other warm-season grasses, one of the causes contributing to slow establishment may be seed dormancy (Adkins et al, 2002), for this reason, it is interesting to understand the mechanisms underlying seed dormancy in these species. Natural genetic variability has been reported for P. dilatatum in its native range (southeastern South America) (Speranza, 2009). The species comprises several apomictic clones and some sexual biotypes, including P. dilatatum subsp.…”

Section: Introductionmentioning

confidence: 99%

Differential incidence of the lemma on seed germination among different Paspalum dilatatum genotypes

2017

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-Paspalum dilatatum Poir. is a promising perennial summer grass forage for temperate regions, but among other factors, slow stand establishment has hindered its adoption. One of the reasons may be seed dormancy. Intraspecific variability in seed dormancy has been reported in P. dilatatum, but the mechanisms underlying this variability remain unclear. In this paper, we focus on the role of seed external covering structures on germination, particularly the lemma. Seeds of apomictic and sexual biotypes of P. dilatatum were subjected to acid scarification and removal of the lemma to study their germination, imbibition rate and sensitivity to ABA. Seeds without lemma showed higher germination than other treatments in dormant genotypes. We found that the lemma delayed but did not prevent water uptake in any genotype. Comparing sexual biotypes, P. dilatatum subsp. flavescens showed higher lemma-imposed dormancy than P. dilatatum "Virasoro", and also higher seed dormancy at the caryopsis level. The thickness of the lemma was not different between these biotypes, so this trait did not explain differences in dormancy. Intraspecific variability of seed dormancy in this species may be attributable to the lemma incidence, however differences in the caryopsis component of seed dormancy should be considered.Index terms: perennial warm-season forage grasses, seed dormancy, seed covering structures, acid scarification.Impacto diferencial da lema sobre a germinação de sementes entre diferentes genótipos de Paspalum dilatatum RESUMO -Paspalum dilatatum Poir. é uma gramínea forrageira perene de regiões temperadas, mas sua utilização é limitada pelo seu estabelecimento lento, entre outros fatores. Uma razão pode ser a dormência das sementes. Tem sido relatada variabilidade intraespecífica da dormência em P. dilatatum, mas os mecanismos envolvidos nesta variabilidade não são claros. Neste trabalho estudamos o papel das coberturas externas sobre a germinação, particularmente da lema. Sementes de biótipos sexuais e apomíticos de P. dilatatum foram submetidos à escarificação ácida e remoção da lema para estudar a germinação, a taxa de embebição e a sensibilidade ao ABA. As sementes sem lema mostraram maior germinação que outros tratamentos em genótipos com dormência. Ainda, a lema retarda, mas não impede a entrada de água. Comparando genótipos sexuais, P. dilatatum subsp. flavescens apresentou uma maior dormência imposta pela lema que P. dilatatum "Virasoro", e também dormência mais elevada ao nível do cariopse. A espessura da lema não foi diferente entre estes genótipos, e portanto esta não explicou as diferenças na dormência. A variabilidade intraespecífica da dormência nesta gramínea panicóide pode ser atribuída às diferenças na incidência da lema. Contudo, diferenças na dormência ao nível da cariopse devem ser consideradas.Termos de indexação: gramínea forrageira perene estival, dormência das sementes, coberturas externas das sementes, escarificação ácida.

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Section: Introductionmentioning

confidence: 99%

“…Natural genetic variability has been reported for P. dilatatum in its native range (south‐eastern South America), including the common apomictic pentaploid biotype (Burson, ), sexual tetraploids (Hickenbick, ; Speranza, ), apomictic hexaploids and other geographically restricted forms (Burson, ; Speranza, ). More recently, genetic variability has also been reported within the pentaploid biotype (Machado et al ., ; Speranza, , ). Morphological and physiological variability has also been reported among P. dilatatum biotypes, including tiller and panicle length (García et al ., ), forage yield and grazing tolerance (Venuto et al ., ), and response to water stress (Couso et al ., ).…”

Section: Introductionmentioning

confidence: 99%

Variability in germination behaviour of Paspalum dilatatum Poir. seeds is genotype dependent

Glison

Viega

Cornaglia

et al. 2014

Grass and Forage Science

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Dallisgrass (Paspalum dilatatum Poir.) is a warm‐season grass, native to South America. Its adoption as a pasture crop has been hindered by low seed germination and slow establishment. However, variability in germination behaviour for this species has never been systematically analysed. For Paspalum spp., dry‐storage and moist cold or warm pre‐conditioning treatments have been reported as effective for the relief or breaking of seed dormancy. In the present work, seed germination responses at 32°C were assayed for sixteen P. dilatatum genotypes, representing its known natural genetic variability, to two moist pre‐conditioning treatments (at 5 and 20°C) and without pre‐conditioning, and three seed storage periods (0, 3 and 6 months). Pre‐conditioning at 20°C showed high germination percentages (>80%), with ratios equal to or higher than pre‐conditioning at 5°C, suggesting that cold is not required to break dormancy. Longer storage times resulted in increases in germination responses for most of the genotypes, while other biotypes showed no effect. Biotypes Virasoro and Chirú showed a remarkably different behaviour with higher germination percentages of untreated freshly harvested seeds. Our results show that diversity for traits involved in seed germination exists among naturally occurring P. dilatatum genotypes and the characterization of these traits should be addressed during ecotype characterization and evaluation of potential domesticates of this species.

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Evolutionary patterns in the Dilatata group (Paspalum, Poaceae)

Cited by 22 publications

References 48 publications

Chromosome numbers and ploidy levels of Paspalum species from subtropical South America (Poaceae)

Chromosome numbers and ploidy levels of Paspalum species from subtropical South America (Poaceae)

Differential incidence of the lemma on seed germination among different Paspalum dilatatum genotypes

Variability in germination behaviour of Paspalum dilatatum Poir. seeds is genotype dependent

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