Cytological evaluations of advanced generations of interspecific hybrids between Allium cepa and Allium fistulosum Showing resistance to stemphylium vesicarium

Authors: KUDRYAVTSEVA, NATALIA - Russian State Agrarian University; Havey, Michael; BLACK, LOWELL - Seminis Vegetable Seeds, Inc; HANSON, PETER - The World Vegetable Center (AVRDC) - Taiwan; SOKOLOV, PAVEL - Russian State Agrarian University; ODINTSOV, SERGEY - Russian State Agrarian University; DIVASHUK, MIKHAIL - Russian State Agrarian University; KHRUSTALEVA, LUDMILA - Russian State Agrarian University

Submitted to: Genes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/27/2019
Publication Date: 3/4/2019
Citation: Kudryavtseva, N., Havey, M.J., Black, L., Hanson, P., Sokolov, P., Odintsov, S., Divashuk, M., Khrustaleva, L. 2019. Cytological evaluations of advanced generations of interspecific hybrids between Allium cepa and Allium fistulosum Showing resistance to stemphylium vesicarium. Horticulturae. 10(3):195. https://doi.org/10.3390/genes10030195.
DOI: https://doi.org/10.3390/genes10030195

Interpretive Summary: Wild species possess numerous valuable traits for the development of new cultivars with improved characteristics. Allium fistulosum L. possesses numerous pest resistances that are lacking in onion (Allium cepa L.), including resistance to Stemphylium leaf blight (SLB). Genomic in situ hybridization (GISH) was used to study the chromosomal composition of advanced generations of interspecific hybrids between A. cepa and A. fistulosum which showed resistance to SLB. GISH analyses showed that F5, BC1F3, BC1F5, BC2F4 plants derived from interspecific hybrids were allotetraploids possessing the complete diploid sets of both parental species. Even though artificial doubling of chromosomes of the interspecific hybrids was not used, spontaneous polyploidization was likely caused by 2n-gametes formation. The saturation with A. cepa chromosomes in backcrossing populations was not revealed. Despite the amphidiploid nature of the interspecific hybrids, recombinant chromosomes between A. cepa and A. fistulosum were identified. Cytoplasmic evaluations with high-resolution melting (HRM) of advanced hybrid generations showed the presence of N cytoplasm of bulb onion that is very useful for onion improvement. These results will be useful for onion breeders interested in introgression of pest resistances from A. fistulosum to onion.

Technical Abstract: Interspecific crossing is a promising approach for introgression of valuable traits to develop cultivars with improved characteristics. Allium fistulosum L. possesses numerous pest resistances that are lacking in Allium cepa L., including resistance to Stemphylium leaf blight (SLB). Genomic in situ hybridization (GISH) was used to study the chromosomal composition of advanced generations of interspecific hybrids between A. cepa and A. fistulosum which showed resistance to SLB. GISH analyses showed that F5, BC1F3, BC1F5, BC2F4 plants derived from interspecific hybrids were allotetraploids possessing the complete diploid sets of both parental species. Even though artificial doubling of chromosomes of the interspecific hybrids was not used, spontaneous polyploidization was likely caused by 2n-gametes formation. Remarkable, the saturation with A. cepa chromosomes in backcrossing populations was not revealed. Despite the amphidiploid nature of the interspecific hybrids, recombinant chromosomes between A. cepa and A. fistulosum were identified. Cytoplasmic evaluations with high-resolution melting (HRM) of advanced hybrid generations showed the presence of N cytoplasm of bulb onion that is very useful for onion improvement.