Re:HYB: Breeding strategies
iris@hort.net
  • Subject: Re:HYB: Breeding strategies
  • From: L* M* <l*@lock-net.com>
  • Date: Wed, 26 Oct 2011 16:00:47 -0400
Tom, does line breeding (as you intend its meaning in your article) using seedlings only descended from one initial cross? Or does it also include additions of outcrosses to the mix now and then? You say "closely related" - not sure how close you mean.
I've looked at pedigrees a lot, but without knowing exactly what the breeder's goal has been, or what the intermediate seedlings had or didn't have along the way, I don't have a good understanding of how to best implement line-breeding to reach my goals. But one of my selection rules has been that if a seedling isn't an improvement of some sort (either trait(s) I'm specifically breeding for or just something I like more than in the parents), I haven't used it for breeding. Sometimes will keep it around just because I haven't gotten around to throwing it away, sometimes just in case it eventually decides to rebloom.
In your article, I notice you say that in line breeding, the above might not always be a good selection criterion: 


 In fact, it's not unusual for the first generation seedlings to be inferior to the parents, apparently lacking their most impressive qualities. This is where line breeding is useful.
I'm just getting started on serious attempts to breed rebloomers, now that a decade+ of breeding oncers has produced a lot of reliable bloomers here in a range of colors and some patterns. My goal is to have 'summer' rebloomers in my growing conditions, which means there has to be a combination of the (probably) recessive 'summer' rebloom genes with all the other growth habits necessary to rebloom, including a relatively high temperature threshold. Without losing all the other bloom traits in subsequent generations.
Lloyd Zurbrigg (plus Earl Hall intros by him) and G.P. Brown's rebloomers have been the most reliable 'summer' rebloom performers I've tried here so far. Plus super performer BELVI QUEEN. So far, 'summer' rebloomers from other hybridizers tend to perform more as fall cycle rebloomers (summers too hot for them?)
I haven't made many trial crosses yet, but have made a few crosses just to try to understand how 'summer' rebloom might be inherited/expressed in my growing conditions. Very unsatisfying so far! I had hoped to at least produce some seedlings to choose among that would be well adapted to my growing conditions, reliably summer bloom and more reliably fertile both ways than the parents.
One example: of maybe a dozen surviving seedlings from IMMORTALITY X MATRIX (both summers here, IMM much more reliably so), only one seedling is a rebloomer and so far, it's been a cycle rebloomer (which Chuck says is a dominant trait).
Are these two parents closely related enough for this to be a line breeding cross? The rebloom seedling is worse than both parents re: form, but not much worse. What to do - breed to something carrying IMM genes with better form (IMM grandkids) but no rebloom or breed to something with rebloom but equally old form? Or not use it at all (which is what I would have thought before reading your article) 

IMMORTALITY =  I Do X English Cottage
MATRIX = Violet Miracle X Brother Carl
BROTHER CARL = Sister Helen X I Do
I DO = Grand Baroque X Amy
VIOLET MIRACLE = (Sign of Leo x (Tuxedo x Purple Duet)) X Violet Classic
ENGLISH COTTAGE = 68-92-Wide: ((Crinkled Ivory x Autumn Sensation) x Grand Baroque) X Cross Stitch
Another example (posted earlier): about 21 surviving seedlings from HARVEST OF MEMORIES X RENOWN. HoM is an early fall cycle bloomer here, I think reported to summer bloom elsewhere, but if it does summer bloom, haven't heard of it being reliable in various climates. RENOWN rarely reblooms here, but has summer bloomed for me once. 5 seedlings from the cross have rebloomed, only one might be a summer, the others cycle. None has form any better than parents (still waiting for the last one to open. but nothing exciting noted during spring bloom). 
Same questions for this cross as the previous one.

HoM = (Magic Memories x Key Lime) X Corn Harvest
RENOWN = Matrix X Suky
KEY LIME = 68-92-Wide: ((Crinkled Ivory x Autumn Sensation) x Grand Baroque) X 68-105-Cream: (((58-49-PA x Flame Kiss) x Java Dove) x Grand Baroque). 
SUKY = Violet Miracle X Victoria Falls
I addressed this question to Tom, because of the article on Breeding Strategies, but also would enjoy hearing other's thoughts on line-breeding. 

Thanks.

Linda Mann east TN USA zone 7

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