Frequent occurrence of unreduced gametes in Triticum turgidum–Aegilops tauschii hybrids

Abstract

Spontaneous chromosome doubling via union of unreduced (2n) gametes has been thought to be the way that common wheat (Triticum aestivum L.) was originated from the hybridization of T. turgidum L. with Ae. tauschii Cosson. Previous works have observed unreduced gametes in F 1 hybrids of Ae. tauschii with six of the eight T. turgidum subspecies. It is not clear, however, whether the formation of these unreduced gametes is a norm in the F 1 hybrids. In the present study, we tried to answer this question by assessing the occurrence frequency of unreduced gametes in 115 T. turgidum-Ae. tauschii hybrid combinations, involving 76 genotypes of seven T. turgdium subspecies and 24 Ae. tauschii accessions. Our data show that these hybrid combinations differed significantly (P B 0.01, F = 11.40) in selfed seedset, an indicator for production of unreduced gametes. This study clearly showed that meiotic restitution genes are widely distributed within T. turgidum. However, significant differences were found between as well as within T. turgidum subspecies and in the interaction of the T. turgidum genotypes with those of Ae. taushii. The possible application of the meiotic restitution genes from T. turgidum in production of double haploids is also discussed.

Natural Pathways to Polyploidy in Plants and Consequences for Genome Reorganization

“…Noticeably, hybrids between divergent genomes present up to a 50-fold increase in the production of unreduced gamete as compared to nonhybrid systems [e.g. Zhang et al, 2010]. In addition, the production of diplogametes appears to be heritable and governed by a few genes [d'Erfurth et al, 2008;Zhang et al, 2010].…”

“…Zhang et al, 2010]. In addition, the production of diplogametes appears to be heritable and governed by a few genes [d'Erfurth et al, 2008;Zhang et al, 2010]. However, the molecular basis underlying the formation of unreduced gamete begins to be unraveled, but much remains to be understood [Brownfield and Köhler, 2011].…”

Evaluation of Interspecific-Interploid Hybrids (F1) and Back Crosses (BC1) in Hylocereus Species (Cactaceae)

“…This phenomenon, including first division restitution (FDR) and second division restitution (SDR), has been documented in cereal crops (Jauhar, 2003(Jauhar, , 2007Matsuoka & Nasuda, 2004;Zhang et al, 2007Zhang et al, , 2010Wang et al, 2010). It has been suggested that the unreduced gametes produced through meiotic restitution may have been a major mechanism for the widespread occurrence of polyploidy in nature (Jauhar, 2003(Jauhar, , 2007Ramanna & Jacobsen, 2003).…”

Breeding triploid plants: a review

“…Noticeably, the frequency of unreduced gamete production occurs up to 50-fold more often in hybrids between divergent genomes than in non-hybrid systems (Zhang et al 2010). Nishiwaki et al (2011) found that new, naturally derived Miscanthus (Poaceae) triploid genotypes were identified more efficiently by flowcytometry screening of seeds harvested from areas where tetraploid M. sacchariflorus F. plants grow sympatrically with diploid M. sinensis F. plants, than by random identification of triploids in the field.…”