Unreduced 3x gamete formation of allotriploid hybrid derived from the cross of Primula denticulata (4x) × P. rosea (2x) as a causal factor for producing pentaploid hybrids in the backcross with pollen of tetraploid P. denticulata

Abstract

Unreduced 3x gamete formation of allotriploid hybrid derived from the cross of Primula denticulata (4x) 3 P. rosea (2x) as a causal factor for producing pentaploid hybrids in the backcross with pollen of tetraploid P. denticulata Abstract A triploid hybrid, which was obtained from interspecific crosses between tetraploid Primula denticulata (2n = 4x = 44) and P. rosea (2n = 2x = 22), successfully produced 11 plants by backcrossing with pollen of tetraploid P. denticulata. Analysis of ploidy level using flow cytometry and chromosome counting in the 11 BC 1 plants revealed that all progeny had much larger DNA contents and chromosome number than both parents. In this triploid-tetraploid (3x-4x) crossing, progeny was predominantly true or near pentaploid presumably produced by the fertilization between true or near triploid female gamete produced from triploid hybrid and diploid pollen of tetraploid P. denticulata. These results suggest that unreduced (3x) or near triploid female gametes were partially produced by single step meiosis, either first-division restitution or second-division restitution process. The zygotes formed by the fertilization between true or near triploid egg produced by single step meiosis in triploid hybrid and diploid pollen produced by normal meiosis of tetraploid P. denticulata might be the only survivors in embryogenesis.

Use of 2n Gametes in Plant Breeding

“…Other examples of the usefulness of 2n gametes for crop improvement in plant breeding have been demonstrated in Alstroemeria, carnation (Dianthus), primrose (Primula), Triticum, cassava (Manihot), blueberry (Vaccinium), cocksfoot grasses (Dactylis), Lotus and Trifolium (Carroll & Borrill, 1965;Hahn et al, 1990;Hayashi et al, 2009;Lyrene et al, 2003;Negri & Veronesi, 1989;Nimura et al, 2008;Parrot & Smith, 1984;, among others. 2N gametes also occur after haploidisation, which is useful for scaling the ploidy level upward again without artificial ploidy doubling (e.g.…”

Tree and fruit traits of progenies from the cross between (Annona cherimola Mill. × A. squamosa L.) × A. reticulata L. and approaches for the introgression of valuable genes from A. reticulata L.

“…In addition to the fruits of some of the segregants resembling one or the other ancestors (A. squamosa, A. cherimola, atemoya and A. reticulata) in terms of shape, size, skin colour and skin surface, there were several novel types of both tree and fruit traits. Hayashi et al (2009) observed that interspecific hybrids have the potential to capture new types of characteristics as well as combine diverse gene pools. Interestingly, in this study, the fruits of some recombinants resembled those of certain allied Annona species.…”

Ploidy and Genome Size in Lilac Species, Cultivars, and Interploid Hybrids

“…Previous studies have produced models based on a holoploid genome size of a theoretical average, single chromosome based on parent genome sizes, and chromosome counts. Although some estimates of aneuploid chromosomes have been based solely on hypothetical chromosome size (Palmer et al, 2009), several studies have tested this model with root squashes and found most of their predictions to be concurrent with the true chromosome number or accurate within two to three chromosomes in Primula (Hayashi et al, 2009), Lilium (Lim et al, 2003), and Calluna (Behrend et al, 2015). Considering these previous studies and the relatively uniform chromosome size observed in lilac (Fig.…”