We made interspecific crosses to facilitate the introgression of desirable traits of Allium roylei into the Alliumcepa genome. After hand-pollination, 906 interspecific F1Allium cepa × A. roylei plants were obtained by in vitro culture via embryo rescue. Nuclear DNA analysis showed that 97.6% of the regenerants were interspecific F1Allium cepa × A. roylei hybrids. Genomic in situ hybridization (GISH) showed that each hybrid had 16 chromosomes, eight of which were identified as A. cepa and eight as A. roylei chromosomes.

Abstract In the previous study we obtained a population of interspecific F1 A. cepa × A. roylei hybrids. In this study, in comparison to the parental species: A. cepa and A. roylei, the F1 hybrids were evaluated in terms of plant morphology, pollen viability, microsporogenesis and female gametophyte. Most of the morphological characters of the F1 hybrids were intermediate as compared to those of both parental accessions. In pollen mother cells (PMCs) of the F1 hybrids abnormalities were observed in meiosis as well as at the tetrad stage. Pollen viability of F1 A. cepa × A. roylei hybrids was reduced to 30.1%. In the F1 hybrids, 45.8% of the analyzed ovules showed developmental disturbances, whereas in 26.7% of the ovules necrotic processes were observed.