Karyological studies of haploid rice plants

Hu, Chao-Hwa

doi:10.1266/jjg.32.28

Cited by 12 publications

(5 citation statements)

References 9 publications

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“…Similar was the case with the 5s locus recombinant DNA (rDNA) in chromosomes 9 and 45s rDNA locus in chromosome 11. These, together with the normal meiosis observed by numerous earlier authors (Hu 1960; Nayar, 1973), indicate a close phylogenetic relationship between the two rice species. This would be difficult to obtain if had they evolved from two different ancestral species ( O. rufipogon and O. barthii ), in two different continents (Asia and Africa), and at two different times (about 7 and 3 millennia BP), as some authors have suggested.…”

Section: The Ancestral Speciessupporting

confidence: 84%

Evolution of the African Rice: A Historical and Biological Perspective

Nayar

2012

Crop Science

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The usual assumption is that African rice {Oryza glaberrima Sfeud.) originated about 3500 yr ago from fhe annual wild rice, Oryza barthii A. Chev., and Asian rice {Oryza sativa L.) was introduced info West Africa in fhe lafe 15fh century CE) by the Europeans. Evidences from several social science and biological science disciplines have been collated and/or reinferpreted to draw the following inferences: (i) There are several accounts of rice culture in northern and western Africa from early centuries of the Common Era; (ii) The Senegamblan monoliths, linked to the fime of origin of African rice as 3500 yr ago, have been carbon dafed fo the 7th century CE; (iii) Neolithic culture had hardly reached tropical West Africa 3500 yr ago; (iv) The characteristics of O. barthii vis-à-vis the two cultivated rices-bigger grains, higher yields, easy crossability with both intermediate features, and weediness-may suggest its hybrid nature; and (v) The rarity of O. glaberrima beginning with the time of its initial identification, acceptance of local farmers to having both rices growing together, repeated discovery of O. glaberrima-Wke forms in non-African rice regions, and prevalence of close colinearify between the two cultivated rices at molecular and chromosomal levels suggest their close relationships. These factors indicate that African rice might have evolved from Asian rice, and that the wild rice, O. barthii, might be a hybrid derivative of the two cultivated rices.

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Section: The Ancestral Speciessupporting

confidence: 84%

Evolution of the African Rice: A Historical and Biological Perspective

Nayar

2012

Crop Science

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“…The ploidy level was confirmed by flow cytometry. In addition, flower sizes were larger than those of diploid plants, which is consistent with the floral characteristics of triploid plants (Hu & Ho, 1963). These results, which clearly demonstrate that a zygote from one egg cell and two sperm cells have the potential to develop and form triploid embryos, also support the hypothesis that polyspermy is not a lethal event in plants .…”

Section: The Development Of Polyspermic Zygotes In Ricesupporting

confidence: 83%

Polyspermy in angiosperms: Its contribution to polyploid formation and speciation

Toda

Okamoto

2019

Molecular Reproduction Devel

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Polyploidization has played a major role in the long‐term diversification and evolutionary success of angiosperms. Triploid formation among diploid plants, which is generally considered to be achieved by fertilization of an unreduced gamete with a reduced one, has been accepted as a means of polyploid production. In addition, it has been supposed that polyspermy also contributes to the triploid formation in maize, wheat, and some orchids; however, such a mechanism has been considered uncommon because reproducing the polyspermic situation and unambiguously investigating developmental profiles of polyspermic zygotes are difficult. To overcome these problems, rice polyspermic zygotes have been successfully produced by electrofusion of an egg cell with two sperm cells, and their developmental profiles have been monitored. The triploid zygotes progress through karyogamy and divide into two‐celled embryos via a typical bipolar mitotic division; the two‐celled embryos further develop into triploid plants, indicating that polyspermic plant zygotes, unlike those of animals, can develop normally. Furthermore, progenies consisting of triparental genetic materials have been successfully obtained in Arabidopsis through the pollination of two different kinds of male parents with a female parent. These different pieces of evidence for development and emergence of polyspermic zygotes in vitro and in planta suggest that polyspermy is a key event in polyploidization and species diversification.

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“…Being consistent with their sterile phenotype and floral characteristics of triploid rice plants (Fig. 3G), 51 the ploidy level of the mature plants was determined to be 3C by flow-cytometry analysis (Fig. 3H).…”

Section: Nuclear Division and Development Of Polyspermic Zygotessupporting

confidence: 64%