Cytology and Reproductive Behavior of Paspalum equitans, P. ionanthum, and Their Hybrids with Diploid and Tetraploid Cytotypes of P. cromyorrhizon

Quarín, Camilo Luis; Norrmann, Guillermo Alberto

doi:10.1086/337667

Cited by 31 publications

(34 citation statements)

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“…Though we failed to produce the targeted hybrids, we had found a way to partially break down the self-incompatibility system and generate selfpollinated progenies. This method is in agreement with previous trials in other Paspalum species like Paspalum equitans and Paspalum ionanthum (Quarin and Norrmann 1987) and Paspalum notatum (Burton and Hanna 1992) where the addition of foreign pollen to the stigmata increased the capacity of self-pollination. Moreover, since some hybrids have been reported from crosses involving different ploidy levels (Norrmann et al 1994) family M 1 was obtained by pollinating spikelets of Q3754 at anthesis (without emasculation) with the tetraploid (2n = 4x = 40) genotype Q3785.…”

Section: Plant Materialssupporting

confidence: 92%

“…However, no apomictic seeds were recovered due to the lack of endosperm development (Naumova et al 1999). Occasional ovules bearing an aposporous embryo sac together with the typical meiotic one have been reported in several diploid Paspalum species, i.e., Paspalum cromyorrhizon, Paspalum equitans, Paspalum intermedium, Paspalum quadrifarium, Paspalum haumanii, Paspalum brunneum, Paspalum rufum and Paspalum notatum (Quarin 1986;Quarin and Norrmann 1987;Norrmann et al 1989;Quarin et al 2001). However, no information about the functionality of the apomeiotic embryo sacs is available so far for these species.…”

Section: Introductionmentioning

confidence: 99%

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Genetic and embryological evidences of apomixis at the diploid level in Paspalum rufum support recurrent auto-polyploidization in the species

et al. 2008

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Gametophytic apomixis is an asexual mode of reproduction by seeds. This trait is present in several plant families and is strongly associated with polyploidy. Paspalum rufum is a forage grass with sexual self-incompatible diploids (2n = 2x = 20) and aposporous-apomictic pseudogamous tetraploids (2n = 4x = 40). In previous work embryological observations of the diploid genotype Q3754 showed 8.8-26.8% of the ovaries having one meiotic plus an aposporous-like embryo sac, suggesting some capability for apomictic reproduction. The objective of this work was to characterize progenies derived from Q3754 to determine if aposporous sacs were functional and generated progenies via apomixis at the diploid level. Re-examination of Q3754 ovaries showed that 12.5% of them contained one sexual plus an aposporous sac confirming previous results. Progeny tests were carried out on two experimental families (H 1 and S 1 ) employing heterozygous RAPD marker loci. Family H 1 was obtained crossing Q3754 with a natural diploid genotype (Q3861) and S 1 derived from the induced self-pollination of Q3754. Genetic analysis of H 1 showed that all individuals derived from sexual reproduction. However, 5 out of 95 plants from S 1 showed the same heterozygous state as the mother plant for 14 RAPD loci suggesting a clonal origin. Further experiments, designed to test the functionality of aposporous sacs by flow cytometric analyses, were carried out on a third family (M 1 ) obtained by crossing Q3754 with the tetraploid plant Q3785. Histograms of 20 M 1 plants showed 15 diploids (75%), 4 triploids (20%) and 1 tetraploid (5%). Triploids and the tetraploid may have originated from functional aposporous embryo sacs. Likewise, the reconstruction of the developmental route of 40 individual seeds demonstrated that 11 of them (27.5%) derived from fertilized aposporic sacs. The results presented in this work indicate that gametophytic apomixis is effectively expressed at the diploid level in Paspalum rufum and could be the foundation of a recurrent auto-polyploidization process in the species.

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Section: Plant Materialssupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Genetic and embryological evidences of apomixis at the diploid level in Paspalum rufum support recurrent auto-polyploidization in the species

et al. 2008

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“…However, some polyploids reproduced sexually and many apomitics were facultative (Burson, 1997). Sexual reproduction in tetraploids has always been reported to occur in individuals with normal meiosis (Moraes-Fernandes et al, 1968;Burson & Bennett, 1971;Quarín & Norrmann, 1987). The conventional Paspalum breeding programs required sexual types for hybridization.…”

Section: Resultsmentioning

confidence: 99%

Chromosome number and microsporogenesis in Paspalum maritimum (caespitosa group; gramineae)

Adamowski

Pagliarini

Batista

2000

Braz. arch. biol. technol.

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“…Very few diploid gametophytic apomicts occur in nature and none of the exceptional cases belong to the grass family (Asker and Jerling 1992). However, a very low expression of apospory has been found in natural diploid Brachiaria decumbens (Naumova et al 1999) and in several Paspalum species (Quarin et al 1982;Quarin and Norrmann 1987;Norrmann et al 1989). Brachiaria and Paspalum belong to the grass tribe Paniceae.…”

Section: Discussionmentioning

confidence: 99%

A rise of ploidy level induces the expression of apomixis in Paspalum notatum

Quarín¹,

Espinoza²,

Martínez³

et al. 2001

Sexual Plant Reproduction

156

140

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The common races of bahiagrass, Paspalum notatum, are tetraploid (2n=4x=40) and reproduce by aposporous apomixis. Paspalum notatum var. saurae is the corresponding diploid (2n=2x=20) sexual race that outbreeds due to self-incompatibility. Chromosome doubling was induced by colchicine treatments in three individual plants from a natural diploid population. Embryological studies demonstrated that one of the induced autotetraploid plants reproduced sexually. The other two autotetraploids were facultative apomicts. These results indicate that an unexpressed gene(s) for apomixis exists at the diploid level. The expression of the trait is ploidydependent. The ploidy dependency may act either on the locus controlling apomixis through some transcription factors or via a secondary locus which requires a higher allele dosage to affect the expression of the main locus.

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Cytology and Reproductive Behavior of Paspalum equitans, P. ionanthum, and Their Hybrids with Diploid and Tetraploid Cytotypes of P. cromyorrhizon

Cited by 31 publications

References 0 publications

Genetic and embryological evidences of apomixis at the diploid level in Paspalum rufum support recurrent auto-polyploidization in the species

Genetic and embryological evidences of apomixis at the diploid level in Paspalum rufum support recurrent auto-polyploidization in the species

Chromosome number and microsporogenesis in Paspalum maritimum (caespitosa group; gramineae)

A rise of ploidy level induces the expression of apomixis in Paspalum notatum

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