Fireblight has been bad in the area since the new strain of fireblight arrived. It made most experts look bad with fb resistant choices like harrow delight. This strain mowes through harrow delight rows like it has no resistance.
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Yes,
Same with apples. I have been chainsaw pruning the especially problematic varieties. Even the PRI stuff is taking a few strikes. It has really made me rethink variety genetics. With all the advances if fruit breeding they are making at the universities, they will always have to go back to wild / open pollinated fruit that develop disease resistance through natural selection.
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Good points about genetic diversity. I agree with you 100% about that. I believe once these PRI type apples start having disease issues it will be a mess to try and clear up.
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Yes it is a matter of time just like the vf genes of the pri apples originally were scab resistant. We know fireblight evolves as well
The purpose of breeding and crossing these apples was never intended to offer disease resistance tbat would last this long. More work needs done with apples and pears.
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Single gene resistance is an exercise in futility. It can only work in certain specific conditions which have not been found yet with any commercial fruit. An example, the strobilurin mushroom produces an anti-fungal compound that is very effective and highly unlikely to be “broken” by any target fungal organisms. Its mode of action is to block a biopath which almost all fungal organisms MUST operate to live. Anti-fungal (and anti-bacterial) single gene resistance found in apple so far has only been of a type which blocks the organism kind of like locking your door. Eventually, the organism can and will find a key to open the door at which point the resistance gene is broken.
Multi-gene resistance holds out more promise. Instead of a single gene blocking infection, many genes are stacked in a plant such that 3 or more block infection. Instead of finding one key, now the organism has to find at least 3 keys which is much less likely to occur. Why isn’t multi-gene resistance breeding a major part of breeding programs? I could give several reasons, but in the end, it gets down to breeders who have not yet found enough genes to be effective and in many cases not yet recognized the inherent limits of single gene resistance.
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I will admit I don’t really understand the science, but I’m not 100% sure the researchers do either. I know with apples, they have identified gene markers for scab resistance. As you said, they will have to keep finding new scab resistant genes as the fungus evolves. I personally want to avoid the new generation of university apple releases because there are developed using transgene (GMO) methods. They splice in Birch or something to make apples that grow vines and bloom continuously allowing them to breed year-round. They never grow out a verity without looking a multitude of gene markers first. All totally unnecessary if we had not virtually eliminated natural selection in apple growing.
Would any of these cultivars be able to reliably produce without spraying for pests or disease?
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Without spray? Only in a few very specific locations with low disease and pest pressure.
39th, breeders do in fact understand the problems though a bunch are still focusing on ineffective single gene breeding plans. Here is an article on pyramiding genes for poly-gene resistance. While it is about rice, the concepts are the same for virtually all plants. You can find a weeks worth of reading by searching for “breeding for resistance”.
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Weren’t most of the Malus floribunda/single-gene apple programs started decades ago? I got the feeling they were mostly releasing crosses they had already to keep the programs going rather than being single-mindedly, single-gene zealots or something. Most of the scab-immune apples have CAR/powdery mildew susceptibility and end up needing sprays many places anyway.
I’ve seen it mentioned before that some pears can be grown no spray. I didn’t know that was region specific.
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I can grow them spray free and Kansas is higher insect and disease pressure than most places.
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are any cultivars better suited to growing spray free (more pest and disease resistant)?
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@Bigmike1116 I’m fairly close to you and I don’t spray any pears. I get a couple mangled up ones, but the bulk of them do just fine. I do sometimes get a black fungus on the leaves that I have to spray for. Forgot what it’s called, but it’s only in really wet years.
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Warren, Karl’s favorite and Turnbull pears are @ 39th parallel and the NJ 55 Suncrisp apple! My personal favorite.
Mid-Missouri zone 6b. While I was growing up, we had an old pear tree in the yard, probably a Bartlett. I was born in 1943, so this pear was probably planted by my Grandparents. Excellent eating pears and it produced almost every year until it was cut down a few years ago. My parents had also planted 4 other pear trees in the yard that the pears tasted and looked same as the Bartlett, but the tree looked more like Kieffer pears. Also excellent eating, very productive and we gave pears to the neighbors every year. I remember spraying the trees a time or two some years but they turned out good either way.
I now live 20 miles West of that farmstead and have one young Bartlett tree and 2 Kieffer pear trees (7 years old) that this year, produced the best pear crop that I have seen. The trees were loaded and the pears averaged .6 pound each. They had very little damage even though I only sprayed once. I now have 10 gallons of pear wine brewing in the barn.
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2001 to 2014… I attempted to start 2 pear trees here… tried several different varieties ( not sure any of them were known to be disease resistent… some I can remember are anjou, bartlet) and as soon as they started blooming FB wipes them out.
I quit trying pears for many years…
A couple years ago… I grafted kiefer, improved kiefer and orient scions to wild callery rootstocks here.
Note… I know that a lot of people dont care for kiefer pears… but we absolutely love them.
A couple years ago… kiefer and orient were still thought to be some of the most FB resistent varieties.
With this new strain of FB is that still true ?
My new trees will be ideal size to graft on other varieties next spring.
I am plannng to add Bell and Potomac.
I grew some Bell scion myself this season.
If kiefer and orient are now known to be quite succeptable to the new FB… sounds like I could be headed for disaster again.
Should I completely top work my new trees changing them over to Warren, Karls Fav, Potomac, Ayers, Bell ?
It would be nice to get a pear tree to live here and produce some fruit.
Thanks
TNHunter
The thing about recommending varieties is that flavor and even pest susceptibility varies from year to year. I tend to be swayed most by the most recent harvest which does not necessarily lead to an accurate assessment.
When we had a multiyear stretch of relatively dry weather results were much different than after a similarly long stretch of weather leaning on wet and grey.
The most reliable evaluations will come from regions with the most consistent weather, like CA. Except those evaluations only apply dependably to the weather in which they are tested, which is true of all fruit variety recommendations. Some varieties perform similarly well in a wide range of weather, some don’t.
My list here would put Harrow Sweet on top. Bartlett is probably the 2nd best to grow here in S. NY of those I’ve tried. These two are both precocious and bear very reliably, unlike many other types. But this list would vary a great deal even site to site in my region. Seckel is a great home orchard pear, unless pear psyla shows up in your orchard. Some sites it does and some it doesn’t. Same deal with Bosc. Korean Giant can be grown at some sites without a single spray. The Asians tend to be immune to pear psyla, but when stinkbugs show up they (including KG) can be very difficult to defend. They don’t show up at all sites.
For home growers it is extremely useful to be able to ripen pears almost fully on the tree because we struggle a great deal in properly timing the harvest- I know I do and that my customers are almost completely at sea.
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I’m almost due west of you, with similar growing conditions. Around here, Orient pears are still recommended as the most disease resistant commonly available pear. I’ve had three or four nursery folk tell me as much over the past year.
I planted two Ayers last year. One had two manageable strikes, one had none. I’m planting Warren, Maxine, Hood, Turnbull, and Orient early next year.
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@mud … best I remember we had some forum members from TX that lost their Kiefer and Orient trees to the new FB.
Has the new FB made it to TN yet ?
Will our kiefer and orient trees survive it ???
The only pear trees that I know of to survive long term and produce good crops here in my county are kiefer.
TNHunter
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