| Autor: |
Hyde, Peter T., Leckie, Brian M., Carpenter, Sara C. D., Lorbeer, James W., Hoepting, Christine A., Ullrich, Maire R., Mutschler, Martha A. |
| Zdroj: |
Crop Science; January 2015, Vol. 55 Issue: 1 p136-145, 10p |
| Abstrakt: |
Onion (Allium cepaL.) lines resistant to Botrytisleaf blight (BLB) were produced by backcrossing the Bs1BLB resistance of Allium royleiStearn into cultivated onion. This study evaluated important issues for the commercial use of BLB‐resistant onions: the relative degree of BLB control possible when Bs1is homozygous rather than heterozygous, the control achieved against multiple pathogen isolates, and the potential for negative traits associated with transfer of Bs1. Homozygous BLB‐resistant onions tested in inoculated growth chamber screens with five distinct Botrytis squamosaWalker isolates and in naturally infested regional field trials showed significantly lower BLB symptoms than susceptible commercial hybrid controls. F1hybrids heterozygous for the Bs1gene showed levels of BLB symptoms between those of the homozygous resistant and susceptible controls, confirming previous reports of partial dominance. The difference in BLB control in plants heterozygous for Bs1compared with homozygous plants was more noticeable under heavier disease pressure. Hybrids heterozygous for Bs1had similar level of BLB control in most of the field trials as their parental homozygous BLB‐resistant lines, indicating that either heterozygous or homozygous BLB resistant hybrids could be used commercially for BLB control. There were no differences in the degree of pathogenicity across the five B. squamosaisolates, which were genetically different based on polymorphism for DNA markers, or among the naturally occurring pathogens present at the six different field locations used. No obvious association was noted between presence of the Bs1resistance gene with unfavorable characteristics such as reduced bulb size or yield. |
| Databáze: |
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