Pear rootstocks influence on Fruit size

Do you feel that pear rootstock influences fruit size? First lets define rootstock One such study analyzes ohxf rootstock vs. seedling rootstock among others The study tested several common varieties of pears and concluded that ohxf was as good as any and better than most with European pears. “In the UC Pear Production and Handling Manual (2007), Reil reports that Comice pear on Quince BA-29 rootstock produces a favorable short wide fruit with a large diameter, while scions of cv. Winter Nelis, Bartlett and the Old Home crosses produce a less desirable long narrow fruit.” as noted here According to Cummins nursery " Pyrus betulifolia (“BET”) seedlings are the rootstocks of choice for Asian pears. A number of extensive field trials have shown that fruit size is increased significantly as compared to other rootstocks." see this link European pears apparently are likely to succumb to decline prior to fruiting on certain rootstocks such as p serotina and Pyrus ussuriensis according to


Thanks for the links, Clark. I found them both useful. Still looks like most of us growing European pears will find our best match with rootstock in the OHxF series, but I was amazed by the number of options.

For a backyard guy like me, growing one pear tree, good health is a paramount concern. Your other posts on fireblight are useful too.


I used a lot of ohxf333 last year and will keep you posted on how it does in terms of fruit size. I suspect BET will produce larger fruit.

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I have found no difference in fruit size regardless of the root stock.


Here is an example of rootstock having influence on scions. Last year I t-bud grafted this pear on a very difficult to graft callery rootstock. The rootstock grew exactly how this tree grows now! They look identical accept for the leaves of course. 333 has reportedly smaller fruit but some growers claim that’s not true.


I strongly suspect that 333 downsizes the fruit in the South(and it does) because it doesn’t get a long enough rest period and doesn’t really like some of our soils down here. That is really nothing more than a guess. I know it sizes fruit fine in the north west and I bet in most other areas with a winter. I did get some decent sized fruit off of a Hosui Asian Pear a few times with thinning. But overall yield was very poor. Anyway I’ll bet 333 will be good for you.


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Thanks Drew time will tell. Callery is a good rootstock here and I’m leaning more back towards it the more I grow other rootstocks. I’m doing a lot of experimenting right now and have every pear rootstock I know of to test with. Harbin is another I really like and BET is doing good as well. The ohxf rootstocks really are good but I don’t think they are the best choice for everything.

Pear rootstock as most everyone is aware is the most important decision a pear grower makes. @BambooMan brought this up in this thread No Farmingdale in OH X F which most of us enjoyed very much and it made much more sense. Here is what experts said about rootstocks in links such as these

" Rootstocks for Pear

Pear Rootstocks

The majority of commercial pear trees are grown on rootstocks. Pear rootstocks impart characteristics such as vigor, precocity, disease resistance, and cold hardiness. The most commonly used rootstock worldwide is some selection of a Bartlett seedling, making it the “standard” rootstock. In rootstock trials, rootstock test scores are often expressed as a comparison to Bartlett characteristics. For example, the test rootstock may impart dwarf characteristics as 70% height compared to a Bartlett seedling tree. In North America, the most common Bartlett-type rootstock is OHxF. OH stands for “Old Home”, a name given to a seedling selection discovered in Illinois by Prof. F.E. Reimer of OSU. It was found to be resistant to fireblight, but was self-infertile. The “F” stands for Farmingdale, the town in Illinois that Reimer discovered the second Bartlett selection. Like OH, it had fireblight resistance, although not quite as good, but it was self-fertile. Old Home and Farmingdale were crossed by L. Brooks of Oregon and the resulting offspring were fireblight resistant, self-fertile, vigorous and had good cold hardiness, making it desirable as a rootstock and receiving a patent in 1960.

The graphic above illustrates the overall influence on tree size* by various rootstock combinations compared to a Pyrus pear seedling. Key to abbreviations and names: BM = P. communis series from Australia; Brossier = P. nivalis series from Angers, France; Fox = P. communis series from the University of Bologna in Italy; Horner = OHxF clonal series from D. Horner (Oregon nurseryman) and selections by OSU-MCAREC; OHxF = ‘Old Home x Farmingdale’ series; Pi-BU = Pyrus series from Germany; Pyro and Pyrodwarf = P. communis selections from Germany; QR = P. communis selections; ‘Adams’, ‘BA29’, ‘EMC’, ‘EMH’, ‘Sydo’ = Quince dwarfing rootstocks (require interstem for most pear cultivars).

Selections shown in gray text indicate antiquated selections no longer in commercial production.
Selections shown in purple text indicate possible susceptibility to pear decline.
*This general classification of tree size may vary for different cultivars due to cultivar/rootstock interactions.
This graphic was adapted from the article by Elkins, Bell, Einhorn, 2012, J. Amer. Pomol. Soc. 66(3):153-163.

Pear varieties growing on OHxF or any Bartlett seedling rootstock tend to be large, non-porous trees. In order to get trees that are more suited to high-density plantings, rootstocks with dwarfing traits and precocity need to be used. In many parts of the world Quince selections are used as rootstocks. This combination will result in dwarfed growth and precocity. However, Quince is not compatible as a rootstock for many varieties of pear such as Bartlett, Bosc, Forelle, Packham, Triumph, Winter Nellis and Eldorado. For these varieties, the use of an interstock (intermediate graft section) must be used. Another problem with using Quince is that most varieties are not winter hardy making it a poor choice for the Pacfic Northwest. However, there are ongoing trials at OSU testing potential Quince selections exhibiting good winter hardiness (Einhorn’s work). "

Many of us now know old home x farmingdale really isnt ohxf at all according to genetic testing Old Home x Bartlett? | Good Fruit Grower
" Old Home x Farmingdale pear rootstocks, which have been widely used by the U.S. pear industry for many years, should actually be called Old Home x Bartlett, it turns out.

Genetic fingerprinting done at the U.S. Department of Agriculture’s National Clonal Germplasm Repository in Corvallis, Oregon, revealed that it is impossible for Farmingdale to be the pollen parent of any of the several OHxF rootstocks tested.

This prompted Joseph Postman, curator of the repository, to retrace the story behind the OHxF rootstocks. It begins a century ago when Oregon State University pomologist Frank Reimer began scouring the world for pear germplasm with resistance to fireblight, a disease that had made its first appearance in Oregon’s Rogue River Valley in 1906. Reimer was the first superintendent of the OSU Southern Oregon Experiment Station near Medford.

Two of his most important discoveries came from a 1915 visit with fruit grower Benjamin Buckman in Farmingdale, Illinois. One was the cultivar Farmingdale, an open-pollinated seedling that Buckman had found near a d’Anjou pear tree on his farm. The other was Old Home, a seedling that had come from a nursery in Illinois some years earlier. Both these trees were completely free of fireblight. Reimer took scion wood of Old Home back to the Southern Oregon Experiment Station and had Farmingdale scions sent to him several years later.

After more than a decade of testing the many pear species in OSU’s collection, Reimer found only three European cultivarsFarmingdale, Longworth, and Old Homethat had excellent blight resistance when used as trunk stocks.

After Buckman died, the original Farmingdale and Old Home trees in Illinois were destroyed, and the trees at OSU became the primary source of nursery stock.

Fireblight resistant

Reimer found in the 1930s that when Farmingdale was used as a pollen parent in crosses with other blight-resistant selections, a high percentage of the resulting seedlings were highly resistant to fireblight, especially when the seed parent was Old Home.

Although crosses between other blight-resistant parents also produced seedlings that were resistant to blight, many of those seedlings became infected when a susceptible cultivar such as Bartlett or Bosc was grafted onto them. In those cases, fireblight could spread from an infected cultivar across the graft union into the rootstock. In contrast, the OHxF seedlings were resistant even to the spread of fireblight from a grafted cultivar.

One of Reimer’s goals was to establish a mother block of Old Home and Farmingdale trees in Medford to generate seed for producing blight-resistant seedling rootstocks. However, Lyle Brooks, owner of Daybreak Nursery in Forest Grove, Oregon, became concerned about the variability of pear cultivars grafted onto OHxF seedling rootstocks. Collaborating with Dr. Mel Westwood at OSU, Corvallis, he set out to develop clonal rootstocks from those two parents.

In 1950, he obtained half a kilogram of seeds from what he described as an isolated block of Old Home trees planted with Farmingdale pollinizers at the Canadian Department of Agriculture Research Unit near Summerland, British Columbia. It now appears that Bartlett must have been planted in the vicinity of the Summerland pear block where Brooks obtained the seeds.


Of the 2,000 seedlings he grew from those seeds, 516 were planted in a nursery block for evaluation. Thirteen of the more easily propagated selections were evaluated in trials for disease resistance and many other traits, including hardiness, precocity, compatibility with pear varieties, and tolerance to pear decline, as well as resistance to fireblight.

Several, including OHxF 69, 87, 97, and 333, were patented in 1988 by Carlton Nursery, which was operated by the Brooks family. The rootstocks have been propagated worldwide and continue to be in high demand, though some lack the size control and precocity needed for high-density orchards.

More than 40 of the OHxF selections are preserved at the National Clonal Germplasm Repository. In 2009, Postman and ARS plant geneticist Dr. Nahla Bassil did genetic fingerprinting of pears in the collection and found that d’Anjou was very likely the maternal parent of Farmingdale, as Buckman and Reimer had suspected.

They then went on to do genetic paternity testing of six OHxF selections (51, 69, 87, 97, 230, and 333), along with a number of other cultivars. All the OHxF selections proved to be related to Old Home, but the tests showed that Farmingdale was highly unlikely to be a pollen parent. On the other hand, there was a strong indication that Bartlett was genetically related to all those selections.


Postman said this explained what had been something of a puzzle to him over the years: While fruit of the OHxF selections in the germplasm collection resembles Old Home, which has a distinctive round shape, it does not at all resemble Farmingdale. The shape of OHxF fruit tends to be intermediate between that of Old Home and Bartlett. Similarly, the foliage of the OHxF selections resembles the foliage of Old Home but not Farmingdale.

Lynnell Brandt, president of Brandt’s Fruit Trees in Yakima, Washington, said his father Everette worked at Carlton Nursery during the time when Brooks was testing the OHxF rootstocks to identify the most promising ones. Lynnell, who joined the staff of Carlton Nursery in the late 1970s, said he felt confident that both Brooks and Westwood believed that Farmingdale was the pollinizing parent.

“Who were we to question those two?” he asked. “They were the world’s leaders in pear understocks. And it seems strange to me, because Lyle would definitely notice the difference between Bartlett and Farmingdale. He would have known the leaves were different.”

Postman said the fact that the OHxF rootstocks have no Farmingdale heritage means that the highly fireblight-resistant Farmingdale is under-represented in the pedigrees of the pear rootstocks currently used in the pear industry as well as in the parent material being used in rootstock breeding programs.

Although Farmingdale is not likely to instill either dwarfing or precocity in its offspring, Farmingdale germplasm should be reconsidered if fireblight resistance is to be an important genetic trait in future pear cultivars and rootstocks, he suggests.

Future DNA fingerprinting in the USDA pear gene bank should help breeders better understand the paternity of parents when making crosses to develop improved varieties, he added.

The question now is whether the OHxF rootstocks should be renamed. The patent expired in 2005, so no one owns the OHxF name.

“Water’s gone under the bridge for so long, so whether they’re Bartlett or Farmingdale, everyone will probably continue to call them OHxF so things don’t get confused,” said Joe Dixon, sales representative with Carlton Plants. “There’s really nobody who would rename them or have the rights to do so, I don’t think.” •

By Geraldine Warner|November 26th, 2013|Apples, December 2013 Issue, Geraldine Warner, Issues, Production


Geraldine Warner

Geraldine Warner was the editor of Good Fruit Grower from 1992-2015. During her tenure, she planned and prepared editorial content, wrote for the magazine, and managed the editorial team. Read her stories: Story Index"

Geraldine Warner // Sep 15, 2015 // Pears // Research // Varieties

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Dr. Kate Evans, Washington State University’s pome fruit breeder in Wenatchee (Geraldine Warner/Good Fruit Grower)

Dr. Kate Evans

The Pacific Northwest fresh pear industry will allocate more than $200,000 over the next three years to launch a pear rootstock breeding program in Washington.

A dwarfing pear rootstock would enable pear growers to shift to more efficient production systems and use labor-saving equipment, as has happened in apples thanks to rootstocks like Malling 9.

“It’s exciting that the pear industry has recognized that this will help them move forward into that next stage of production,” said Dr. Kate Evans, Washington State University’s pome fruit breeder in Wenatchee. “Think about the huge advantages you have in apple production because of dwarfing rootstocks and high-density plantings, and all the mechanization you can bring in.”

Small trees and fruiting walls also produce fruit of more consistent maturity than the big, old trees that are still common in the pear industry, research shows.

It’s almost a century since Malling 9 was discovered as a chance seedling in France. Though many more dwarfing apple rootstocks have been introduced since then, there has been much less effort directed towards developing Pyrus rootstocks for pears.

That’s partly because pear growers in other parts of the world have been able to shift to high-density systems using quince (Cydonia) rootstocks.

Before joining WSU in 2008, Evans worked for East Malling Research in England, where she released the Quince H rootstock.

Quince H is being used with success in Europe, particularly in Italy. Even in Poland, which has cold winters, growers use dwarfing quince rootstocks with the idea that they will just replace the orchard if the trees succumb to cold, perhaps once every 20 years or so. They still find the plantings to be profitable.

But quince is not thought to be cold hardy enough for the Pacific Northwest. Also, some rootstock-variety combinations are better than others, and there are reports that d’Anjou, Washington’s top pear variety, is not productive on quince.


With the new funding, Evans plans to start a rootstock breeding program in Wenatchee. WSU already has some crosses between Bartlett, d’Anjou, and Comice that were made by a graduate student for a previous project. WSU genomicist Dr. Amit Dhingra has been maintaining that material in Pullman.

Recent research at Oregon State University in Corvallis revealed that the Old Home x Farmingdale 87 rootstock, which is widely used in the Northwest, was misnamed and is actually a cross of Old Home and Bartlett. (See “Old Home x Bartlett?” in the December 2013, Good Fruit Grower.)

“That made us think that perhaps there was some value in looking at some of those Bartlett seedlings we had,” Evans said. “We had this material, so why not?”

Initial screening shows a wide variation in vigor. Some of the most promising candidates will be planted in Wenatchee for a small-scale trial to find out how well they control the vigor and size of commercial pear varieties used as the scions. Dhingra is also looking at how well they would propagate. A common problem with Pyrus rootstocks is they don’t root very well.

Evans also plans to make new crosses. She has a range of germplasm at WSU’s Sunrise Orchard in a pear rootstock parent collection she established five years ago. Having good material to cross is the key to starting a breeding program, she said.

Most of this material came from the pear collection at the National Clonal Germplasm Respository at Corvallis, Oregon. Evans spent some time walking around the collection looking for interesting species. One that she picked out was Farmingdale, which, though not dwarfing and not a parent of OHxF 87, does have high resistance to fire blight.

“One of the nice things about Pyrus is it’s quite diverse, and for the most part willing to cross pretty well,” she said. “There’s an awful lot of opportunity to bring in some germplasm that would suit this industry.”

A benefit of using what she calls “slightly exotic germplasm” is that it can introduce other important characteristics, such as resistance to fire blight and tolerance of pear decline, as well as dwarfing.

Longer process

Breeding new rootstocks tends to be a longer and more difficult process than breeding varieties, Evans said. That’s because rootstocks can’t be crossed until they grow into trees and bloom. Also, it’s more difficult to evaluate the growth characteristics of a rootstock than to spot an exciting new apple growing on a tree. The differences are more subtle.

“My personal view is the amount of testing you should do of a new rootstock is more than for a new scion because if you make a mistake and release a new rootstock out to the industry, it can have a much more devastating long-term consequence than a new scion,” she said.

Advanced selections need to be tested with different scions and in different growing conditions, and she likes to collect at least six or seven years of data from trials. “What inevitably happens is you have to go through a few rounds of that to cut the numbers down,” she said.

That’s why on-going support by the pear industry was important.

“I wanted to start this with a reasonable level of commitment from the industry that they would be prepared to look at this in a long-term way,” Evans said. “It’s a waste of everyone’s time, effort, and money to go through the very early part and not follow through.”

Figuring out how best to multiply any promising selections for replicated trials will be part of the project. Dhingra, who is collaborating with Evans, brings expertise in tissue culture and micropropagation.


Genetic markers enable scientists to identify traits in plant DNA from young seedlings without needing to grow a whole tree, but markers will not be developed for the project initially. Evans said some markers have been identified for the dwarfing trait in apples and she and her colleagues plan to see if those might work in pears, since the fruits are related.

Dr. David Neale, geneticist at the University of California, Davis, is working on a project jointly funded by the Northwest and California pear industries to assess the genetic variation of pears in the national repository in Corvallis, Oregon. The genetic data will be overlayed with the visible, or phenotypical, variations observed between the pear species.

“Long term, we’re trying to do more and more phenotyping of the collection so we can potentially develop more DNA-based tools to help us with breeding selection,” Evans said.

Neale, Dhingra, and Evans are part of a Pear Genomics Research Network created about two years ago to coordinate the various research efforts relating to development of pear rootstocks. Other scientists involved include Dr. Richard Bell and Joseph Postman with the USDA ; Rachel Elkins and Dr. Pedro Martinez-Garcia at UC; Dr. Stefano Musacchi at WSU; and Dr. Todd Einhorn with OSU.

Einhorn is heading a project to evaluate elite pear rootstock material, including quince and Amelanchier selections (read “Promising pear rootstocks,” from the April 15, 2015 issue.

Both quince and Amelanchier are pome fruits. Some of the best selections will be planted in replicated trials in Washington and Oregon. •

By Geraldine Warner|September 15th, 2015|Geraldine Warner, Pears, Research, September 2015 Issue, Varieties


Geraldine Warner

Geraldine Warner was the editor of Good Fruit Grower from 1992-2015. During her tenure, she planned and prepared editorial content, wrote for the magazine, and managed the editorial team. Read her stories: Story Index""


Does anybody else worry that there are way too few rootstocks? We’re essentially growing monocultures from the trunk down. It sure seems like we’re setting ourselves up for another big disease outbreak once something comes along that can target one of the 5 or 6 roots grown everywhere.


50% of my rootstocks are genetically unique callery but they are difficult to graft in some cases. It can be challenging to predict their behavior. The other question becomes what influence does the rootstock have over the food value of the pear? Fruit size? Disease resistance, pest resistance, allergies etc.? All that said i agree its a very bad idea for every rootstock to be ohxf rootstock because a new pest or something else will come up and all the eggs so to speak would be in one basket. To add to this slightly its even more concerning bartlett aka williams is a parent of so many crosses we use to graft. We definately need to breed in more genetically diverse material!


As i continue investigating rootstocks i keep coming back to old home and i really wonder about the origin of it

This rootstock designated |Status:|Not Available|
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This rootstock reminds me a lot of my small yellow pear. Its on my to grow list! According to the USDA its one of the old home pears called # PI 541238

Pyrus communis L.

’OH 50’

Here is another i plan to work with (Not available to order)

PI 541237

Pyrus communis L.

’OH 20


Very interesting articles on pear rootstocks! Thanks for posting!

I was interested to read about quince rootstocks not hardy enough for the Pacific Northwest, where I live. I’ve read a number of things about quince not being ideal for pears, but a number of years ago I bought a Maxie pear on quince from a local nursery. I wanted a better rootstock, but that is all they had. I don’t know which quince rootstock.

That variety isn’t the greatest, so far but the tree survived the historic winter a few years ago. For midwestern growers, I know it’s not that cold, but it was 9 F in my yard.

The Pacific Northwest has diverse climates, from maritime in the west, to high desert in the east, so it’s hard to have a one size fits all recommendation. I wont be too upset if some winter my pear on quince doesn’t make it, although it’s now a frankentree with four other varieties.

I wonder if quince on quince is also not hardy enough, or if its just those tootstocks or just the quince/pear combination?

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They are getting closer everyday on better rootstocks in your area because of the need that exists. The experts are reacting to the discovery of old home x bartlett being the ohxf cross. Farmingdale im growing to fruit now and making new crosses this year. Those fruitlets on that tree contain seeds for some future rootstocks. Im already growing out some from my small yellow pear. Im also looking hard at many of the canadian pears. Harrow delight is likely a better rootstock than what we use currently. It’s grafts have taken 100% of the time on everything i grafted it to. Once i have oh20 and oh50 i can determine what growth habits they have and likely match them with things i grow already to determine how to best use them in the future.

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My Maxie pear has this root stock. Is anyone familiar with it? I tried to look it up but couldn’t find anything about it.

Do you mean “Prem 1P” ? If so I believe that refers to the patent on Maxie, not the root stock. I haven’t known Stark to specify what root stock they’re using.

This is the information your looking for Sneak peak at Stark Brothers rootstocks . On asian pears they are known to use BET rootstock on dwarf euros they are known to use quince…

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The area where it says Prem1P is the same area where the root stock is listed on my other tags. Here are a couple other examples. The Chojuro is on OHxF 333 and the Black Tartarian Cherry is on Mahaleb Seedling (sorry that pic is not good)

I was trying to look up Prom1P before and not finding anything. When I looked up Prem1P it does show that to be the patent name for the Maxie pear. So it doesn’t look like the dwarfing rootstock is listed on that tag.

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Interesting observation that they are using 333, im just now seeing this but reading up on it now. I suspect they did that strictly for faster fruit production. 333 does influence pears to fruit faster.

I will have some BET rootstock sent to me sometime next month and I guess since I will have both Euro and Asian pears then that is probably the best choice I could have made since I want them all to be very vigourous and healthy as can be… and also I had to buy 10 at a time and figured it would be more economical to get this one as well.

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