We made interspecific crosses to facilitate the introgression of desirable traits of Allium roylei into the Allium cepa genome. After hand-pollination, 906 interspecific F1 Allium 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 F1 Allium 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.
Alicja Chuda, Karolina Kłosowska and Adela Adamus
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.
Maria Pobożniak, Marta Leśniak, Alicja Chuda and Adela Adamus
Field experiments on the susceptibility of onion to thrips infestation were carried out in 2012 and 2013. The investigation used 18 cultivars and 5 breeding lines of Allium cepa, and the species A. fistulosum and A. roylei. In 2012 A. fistulosum was one of the most infested plants, whereas in 2013 infestation was no more than average. The most infested cultivars of A. cepa were ‘Efekt’, ‘Alonso F1’, ‘Alibaba’ and ‘Wama’ and the ‘NOE5’ breeding line. In 2012 the extent of damage ranged from 12 to 55%, in 2013 from 20 to 30%. The ‘NOE2’, ‘NOE3’ and ‘Wama’ cultivars were the most seriously damaged by thrips. Leaf damage to A. fistulosum was minimal. No damage was caused to the wild species A. roylei by feeding onion thrips.