Hi, nelli.
Best wishes on your search for rust resistant varieties. The ATP database is a good start. (I've been busy making lists...
)
I recently ran across this blog
http://daylilybreeder.blogspot... , which may be of interest to some people here, particularly with respect to the entries on rust resistance. The author has a 12-part series on breeding for rust resistance, beginning in Nov 2013, as well as a 2-part series in Oct 2014, which focuses on the work of Ron Reimer in hybridizing for rust resistant diploids.
I had already been taking *some* care in my parents when making my crosses (wrt rust resistance), but now I am inspired to be much more focused (or ruthless) about it. I may have to use *some* rusty plants (because of certain genes), but one of my goals is to improve rust resistance (or maintain it, if there is already some high degree of resistance) in the next generation, regardless of whatever other traits I am trying to propagate.
It does pose an interesting conundrum for those of us who want good looking gardens, but who also want to hybridize with an eye to rust resistance. The issue is wrt evaluating seedlings for rust. I am not talking about climates where rust is not much of an issue (which makes evaluation difficult), although that is certainly one aspect of it, but rather the need to supply a source of rust in order to evaluate the seedlings for resistance (or not). That need more or less mandates the permanent residence of some number of rust buckets (to provide the rust), and rules out spraying (fine with me, maybe not so fine for other people in other gardens). I was going to keep a few rust susceptible daylilies around regardless (one I need for certain genes, others I like for their flowers), but that in turn means that even if the bulk of my daylilies are resistant, my garden will still never be "clean" of rust (if anyone's garden in the warm winter areas ever can be). That, in turn, rather makes this whole thread pointless - no use fretting over rusty pot soil if one is going to be keeping rust buckets around anyway! Doh!
Normally I would not care about having a "pristine" clean garden. My garden is a private one and for our pleasure, and so long as it is "clean enough" (the majority of the daylilies being resistant and showing little rust), that it is good enough for me.
But it does raise the interesting What-If question.... that of What If I ever hybridized a rust resistant daylily worthy of registration and introduction. (I'm not holding my breath, but hope springs eternal...) If one is required to spray in order to sell, that means no selling - because I ain't spraying (and not just because of the need to evaluate seedlings). And even though the plant may be resistant to rust (in *my* garden), hypothetically it might still *carry* rust (because it has been continually exposed since it was a seedling) which might then produce (a few) spores in a different garden, even if I did spray (which I'm not going to).
So how does one introduce a rust resistant plant once one has one? Even with spraying, one can't claim (at least in a warm winter garden) that the plant is clean (the sprays just suppress any rust). There seems no solution here, short of packing up the garden and moving to Zone 5 (which we are not about to do).
