Artificial interspecific hybrids (3n) of tetraploid dojo loach Misgurnus anguillicaudatus (TTTT) and diploid large-scale loach Paramisgurnus dabryanus (PP) were viable. Allopentaploid loaches (TTTTP) were produced by cold-shocking the fertilized eggs of TTTT females fertilized with sperm of PP males. The TTTTP were viable and well developed. As there are currently no reports on the fertility and gamete ploidy of TTTTP, artificial propagation and ploidy analyses were conducted to determine them. The ovaries of TTTTP were well developed with primary oocytes and secondary oocytes; the testes were sterile with low-density sperm-like cells. By backcrossing with mature TTTT, TTTTP were found to be female fertile and male sterile. The fertility of female TTTTP was low; they produced few viable diploid eggs and a few inviable triploid and aneuploid eggs. Ploidy analysis of cold-shock-induced progenies of TTTTP × TTTT indicated that TTTTP could generate viable diploid eggs, along with diploid second polar bodies. The results of this study are helpful for further understanding of loach polyploidization and should encourage more investigations on hybridization and gamete formation in loaches.

中文翻译：

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四倍体道场泥鳅雌性和大型泥鳅Paramisgurnus dabryanus雄性异五倍体后代的生育力和配子倍性

四倍体道场泥鳅 Misgurnus anguillicaudatus (TTTT) 和二倍体大型泥鳅 Paramisgurnus dabryanus (PP) 的人工种间杂种 (3n) 是可行的。异五倍体泥鳅 (TTTTP) 是通过对 TTTT 雌性受精卵与 PP 雄性精子进行受精而产生的。TTTTP 是可行且发展良好的。由于目前没有关于 TTTTP 的生育力和配子倍性的报道，因此进行了人工繁殖和倍性分析来确定它们。TTTTP卵巢发育良好，有初级卵母细胞和次级卵母细胞；睾丸是无菌的，有低密度的精子样细胞。通过与成熟的 TTTT 回交，发现 TTTTP 是雌性可育和雄性不育。女性TTTTP生育率低；它们产生了很少的可存活的二倍体卵和一些不可存活的三倍体和非整倍体卵。冷激诱导的 TTTTP × TTTT 后代的倍性分析表明 TTTTP 可以产生可行的二倍体卵以及二倍体第二极体。本研究结果有助于进一步了解泥鳅多倍体化，并应鼓励对泥鳅杂交和配子形成进行更多研究。