Triploid and pentaploid breeding is of great importance in agricultural production, but it is not always easy to obtain double ploidy parents. However, in fishes, chromosome ploidy is diversiform, which may provide natural parental resources for triploid and pentaploid breeding. Both tetraploid and hexaploid exist in Schizothorax fishes, which were thought to belong to different subfamilies with tetraploid Percocypris fishes in morphology, but they are sister genera in molecule. Fortunately, the pentaploid hybrid fishes have been successfully obtained by hybridization of Schizothorax wangchiachii (♀, 2n = 6X = 148) × Percocypris pingi (♂, 2n = 4X = 98). To understand the genetic and morphological difference among the hybrid fishes and their parents, four methods were used in this study: morphology, karyotype, red blood cell (RBC) DNA content determination and inter-simple sequence repeat (ISSR). In morphology, the hybrid fishes were steady, and between their parents with no obvious preference. The chromosome numbers of P. pingi have been reported as 2n = 4X = 98. In this study, the karyotype of S. wangchiachii was 2n = 6X = 148 = 36m + 34sm + 12st + 66t, while that the hybrid fishes was 2n = 5X = 123 = 39m + 28sm + 5st + 51t. Similarly, the RBC DNA content of the hybrid fishes was intermediate among their parents. In ISSR, the within-group genetic diversity of hybrid fishes was higher than that of their parents. Moreover, the genetic distance of hybrid fishes between P. pingi and S.wangchiachii was closely related to that of their parental ploidy, suggesting that parental genetic material stably coexisted in the hybrid fishes. This is the first report to show a stable pentaploid F1 hybrids produced by hybridization of a hexaploid and a tetraploid in aquaculture.

Progenies derived from rice (Oryza sativa ssp. japonica) plants pollinated by Oenothera biennis exhibited numerous morphological and developmental traits. Some variant individuals appeared in generation D2. From generations D3 to D6, a large number of variants were observed, showing distinct variable traits including giant embryos. Statistical analysis on D6 lines showed significant differences between progenies and their rice parental line in several main traits, including plant height (49.2–164.5 cm), panicle number (12.1–38.2), panicle length (20.3–30.3 cm), length of sword leaf (13.8–57.5 cm), leaf width (11.1–25.2 mm), grain number of main panicle (142.0–367.0), percentage of seed setting (0.8–99.0%), 1000-grain weight (19.7–33.8 g) and time from germination to panicle emergence (90.0–108.0 days). Most of the variable coefficients were above 20% (the highest was 40.8%). Through pedigree selection of these plants, genetically stable lines were obtained, which are useful for rice breeding. Results from amplified fragment length polymorphism (AFLP) analysis showed that several rice lines contained extensive genetic variations, which included disappearance of rice parental bands and/or appearance of novel bands.