In this installment we will look at techniques of rating rust resistance and susceptibility. I want to stress that this is not a comprehensive coverage of the subject, but is a look at the techniques I use and how those techniques compare to the methods of various other breeders. A comprehensive discussion of techniques and methods of rating rust resistance in daylilies is beyond the scope of a simple blog. This is a complex subject and I hope this small overview can spur further thought and discussion.
One final point I want to touch on is that any garden can have variable environmental factors, while different gardens will likely represent environmental differences as will different regions around the continent. Environment can influence the expression of resistance. One report from one year from one garden is highly unreliable. Multiple reports representing many gardens gives a much better chance of understanding actual resistance. When multiple years are also factored in from multiple gardens, that gives a much better picture of actual resistance. With that said though, even one garden can make for better evaluation by using multiple clumps of the same cultivar or seedling scattered throughout the garden. Both multiple clumps and random arrangement, even within one garden, gives a much better insight into the actual resistance of a given plant and helps to neutralize environmental effects. This is but one technique to help eliminate environmental effects and come to a better evaluation of actual resistance. There are also other techniques used by professional researchers to formulate statistical models that can help to eliminate environmental effects.