Review Apomixis in cassava: advances and challenges

Freitas, D.Y.H.; Nassar, Nagib M. A.

doi:10.4238/2013.april.2.14

Cited by 10 publications

(11 citation statements)

References 26 publications

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“…The relationship between polyploidy and apomixis has already been described in natural polyploids (Gustafsson, 1946;Firetti-Leggieri et al, 2013), in interspecific hybrids of cultivated species such as in the genus Manihot Mill. (Freitas and Nassar, 2013), and in experiments of artificial chromosome duplication of Paspalum notatum var. saurae diploid individuals, which also present natural polyploids (Quarin et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Polyploidy and apomixis in accessions of Senna rugosa (G.Don) H.S.Irwin & Barneby

Resende¹,

Prado²,

Davide³

et al. 2014

Turk J Biol

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Senna rugosa (G.Don) H.S.Irwin & Barneby (Leguminosae) is a species from the Brazilian Cerrado commonly used for medicinal purposes. Chromosome variability (n = 14 and 28) described for this species indicates the occurrence of chromosome races and recent polyploidization in its evolution history. The aim of this study was to verify the relationship between ploidy level and occurrence of polyembryony in 5 accessions of S. rugosa. Cytogenetic analysis revealed the type of interphasic nuclei, chromosome number and morphology, and nuclear DNA content. Frequency of polyembryony was estimated by germination test. Pollen grain viability was estimated by different techniques. There was variability among the accessions of S. rugosa for interphasic nucleus type (semireticulate and nonreticulate), genome size (2.57 to 2.80 pg/2C), and polyembryony frequency (from 2 to 4 embryos). Pollen grain viability was 2.5% to 20%, depending on the technique used. Numeric chromosome variability was found among meristematic cells from each individual (2n = 28 to 2n = 112), with prevalence of 2n = 56. In mitotic metaphases with 2n = 56, all chromosomes were metacentric and of similar size. The data described, combined with previous descriptions of irregularities in chromosome pairing, suggest that S. rugosa is an autopolyploid facultative apomictic species, with interpopulation variability for level of apomixis expression.

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Section: Introductionmentioning

confidence: 99%

Polyploidy and apomixis in accessions of Senna rugosa (G.Don) H.S.Irwin & Barneby

Resende¹,

Prado²,

Davide³

et al. 2014

Turk J Biol

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“…Although female gamete formation has been reported for L2 (Burge et al, 2002), there is evidence that L1 may be involved in apomictic embryo sac formation, besides L2 itself (Koltunow and Grossniklaus, 2003). Ploidy relationship and low frequencies of polyembryo sacs in cassava have been reported (Nassar et al, 2010;Freitas and Nassar, 2013).…”

Section: Discussionmentioning

confidence: 99%

“…Polyploidy has also been cited in relation to polyembryonic formation and apomixis occurrence in cassava (Freitas and Nassar, 2013). We tried to determine in this study the limit and potential of polyploidization in inducing alterations in polyembryony and consequently apomixis rate.…”

Section: Introductionmentioning

confidence: 99%

Cytogenetic and anatomic behavior of cytochimeras and total polyploids in cassava

Hashimoto-Freitas¹,

Nassar²

2013

Genet. Mol. Res.

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ABSTRACT. Cassava periclinal cytochimeras, cultivars, and interspecific hybrid and polyploid types were studied in relation to embryonic, cytogenetic, and anatomical behavior. Their apical shoots, pollen grains, male and female buds, roots, stomata, and flowering period were analyzed. Chimeras exhibited increased size of L1 and L2 cells. Polyploidy led to enlargement of stomata in chimeras whereas L2 gave tetraploid chromosome configurations, tetrad irregularity, decrease of pollen viability, and increase in frequency of polyembryo sacs. The chimeric composition of tetraploids L1 and L2 and diploid L3 expressed a notable epigenetic effect seen in a marked enlargement of edible roots compared to total diploid. One of the chimeric types was accompanied by complete flowering inhibition. Pollen viability and diameter appeared to be reliable markers to determine ploidy levels.

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“…Parthenogenesis (a form of "apomixis") refers to the development of a haploid embryo from a reduced egg nucleus (n) in an asexual embryo sac without fertilization by the sperm nucleus (Palmer and Keller, 2005;Acquaah, 2007). This has been investigated in various crops since the 1940s (Freitas and Nassar, 2013). It occurs naturally or spontaneously and is widely distributed in plants including a few species of agricultural importance.…”

Section: Introductionmentioning

confidence: 99%

Exploring the induction of doubled haploids in cassava through gynogenesis

Baguma¹,

Kawuki²,

Mukasa³

et al. 2019

Afr. J. Agric. Res.

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Production and use of double haploids is important for attainment of systematic genetic gains, and indeed several plant breeding programmes have benefited from it. Gynogenesis, the in vitro culture of unfertilized ovules and/or embryos has specifically been exploited in several economically important crops but not cassava. In this study, we examined possibilities of generating doubled haploids (DH) in cassava through gynogenesis, by bagging female flowers of selected varieties to prevent pollination. A total of 2,466 flowers across 32 elite cassava varieties were bagged for a period of one-to-three days. Early embryo rescue and ovule culture were done at 7 to 42 days after anthesis. Consequently, 517 fruits (21%) were harvested and dissected to obtain 97 seeds from which 47 unique embryos and 18 callus lines were obtained in vitro. Only six of the rescued embryos (12.8%) regenerated into plantlets. Upon undertaking ploidy analysis and single nucleotide polymorphism (SNP) genotyping, it was established that all samples analyzed (regenerated plants and calli) were diploid. SNP genotyping revealed increased homozygosity (up to 85.7%), but no doubled haploids were noticed. The knowledge generated is a significant contribution towards understanding cassava flowering biology and thus a foundation to on-going efforts towards developing protocols for generation of cassava DH.

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Review Apomixis in cassava: advances and challenges

Cited by 10 publications

References 26 publications

Polyploidy and apomixis in accessions of Senna rugosa (G.Don) H.S.Irwin & Barneby

Polyploidy and apomixis in accessions of Senna rugosa (G.Don) H.S.Irwin & Barneby

Cytogenetic and anatomic behavior of cytochimeras and total polyploids in cassava

Exploring the induction of doubled haploids in cassava through gynogenesis

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