Article (magazine)  (2023)  
 
...our data confirm the previously reported ploidy of 10 accessions and dispute the ploidy of the other six accessions, i.e., Knock Out®, Home Run®, Miracle on the Hudson®, Blushing Knock Out®, Double Knock Out®, and Oso Easy Paprika®. Each of these six cultivars was previously reported as triploid (D. Zlesak, Per. Comm.).... However, the relative genome sizes determined by flow cytometry indicate that each cultivar is tetraploid...

Double Knock Out^® 'Radtko', Source/Accession MHCREC [Mountain Horticultural Crops Research and Extension Center, Mills River, NC]  ...Estimated ploidy level(x) 4

Article (magazine)  (2010)  Page(s) 1781.  
 
Double Knock Out ® (RADtko), under consideration for future Earth-Kind rose trials, Shrub, 2004, William Radler, Ploidy 3x ....

Website/Catalog  (2007)  Includes photo(s).
 
Award: Gold Medal, Australian Rose of the Year, Marion de Bomhe Memorial Award, Best Floribunda (Rose Hills award).
Name: Double Knock Out®
Type: Floribunda, Fragrance: Mild
Habit: Compact red buds with robust dark green foliage and deep maroon tips
Breeder: William Radler for Meilland International, Tassin, France
Exhibitor: Corporate Roses, SA