It took 40 years before weather conditions were wet enough for botrytis to affect lilies here at the farm in Lucky Lake, Saskatchewan. Since 2010 botrytis resistance has been an obvious goal. Here are three cultivars that show good resistance. Tetraploid pollen used on Iowa Rose results in easy seed. Poorer results on Morden Butterfly. Not Centurion being a diploid asiatic lily is easy to breed with.
Not Centurion
Morden Butterfly, W.G. Ronald
Iowa Rose, Prochaska, Hartle-Gilman