ARS | Publication request: GISH ANALYSIS REVEALS CHROMOSOME REGIONS OF ALLIUM FISTULOSUM AMONG PROJENIES FROM ADVANCED BACKCROSSES TO ALLIUM CEPA

Submitted to: The Allium Improvement Newsletter
Publication Type: Research Notes
Publication Acceptance Date: March 15, 2001
Publication Date: N/A

Technical Abstract: Allium fistulosum L. is a cultivated species closely related to the bulb onion (Allium cepa L.) that possesses several important disease resistances. Although the first interspecific hybrids between bulb onion and A. fistulosum were reported over 60 years ago, no bulb-onion cultivars with a beneficial trait from A. fistulosum have been developed. Recent studies indicate that the failure to introgress beneficial traits from A. fistulosum by backcrossing to bulb onion may be due to nuclear-cytoplasmic incompatibilities that occur when the interspecific hybrid possesses the cytoplasm of A. fistulosum. We used in situ genomic hybridization (GISH) to score the frequency and types of recombination events between the genomes of A. fistulosum and bulb onion in advanced backcross generations. One plant was identified that carried a complete chromosome from A. fistulosum and two other plants carried portions of chromosomes from A. fistulosum. The ends of A. fisutlosum chromosomes tended to fluoresce strongly, indicating that euchromatic regions may be concentrated near the centromeres.