Bud sport mutation varieties

I thought it would be interesting to talk about fruit tree cultivars that are presumed to be bud sport mutations.

The age is now upon us when researchers could actually compare the genome of the original and bud sport and understand the function of the genes that had been altered. It seems like the universities looking for a summer research project for their interns could find this topic to be “low hanging fruit.” Here would be my list of cultivars that are bud sports of interest:

Steindorf Blenheim - flowers and fruits 30 days later than Blenheim. Originated on a Blenheim tree so whatever difference makes it do that was only one gene (presumably). This cultivar is really interesting - how does one mutation make it shift its photoperiod by 30 days? I have fruited this in my yard and it was amazing.

Smith Red Valencia - it is curious how a mutation gets this Valencia orange to express anthocyanins in its fruit. Mine has not fruited yet.

Redsweet apricot - reputed to be another budsport of Blenheim, but red, and has some plum characteristics, which was expressed to me by a grower. Another Blenheim grower in Hollister reported getting a red sport of Blenheim so apparently Blenheim has it in itself to do that. It would be interesting if the gene for Redsweet turns out to be the same as the gene for Smith’s Red Valencia.

Broken Heart plum - from Elephant heart, but incomplete and variable color. This one is probably easier to understand, as a mutation that caused incomplete expression of color. I grow it in my yard, I had grafted it out of curiosity more than anything but it really is an amazing plum.

Tropic Gold apricot - this is reported to have originated as a sport of Blenheim, though the origin is more obscure. They just found a tree that seemed like Blenheim except it fruited more consistently in low chill areas. It would be interesting to see how it differs from Blenheim in its actual DNA. I suspect it is just the same as Blenheim. But if it really is better adapted to low chill, then the mutation that made this happen would be of interest.

Those are the bud sports I grow. Are there other cultivars you grow that originated as bud sports? I doubt academics read our site but it would be neat if a listing of bud sports one day led to uncovering of the genetic basis of these traits.


Such an interesting subject. Most of the identified bud sports have something visibly obvious that leads them to be noticed. It makes you wonder what small changes exist that have not been noticed.


Probably a lot! I’ve read that there’s often a fair amount of drift within a given variety as it’s propagated down the line. I think that’s a lot of the reason many nurseries will keep a dedicated “mother tree” that they source budwood from, to maximize the chances of being true-to-type.


Perrine Giant Yellow Transparent apple, a tetraploid budsport of Yellow Transparent. Found in the 1940s, IIRC. More vigorous tree than YT, with significantly larger fruit.

Converse Major pecan, budsport of Major, noticed by the late Henry Converse…a branch in one of his Major trees that consistently produced nuts 10-15% larger than typical.


How winter hardy is this apricot? Might this be a way those of us in z3/4 could beat the spring frosts that usually do in the apricots around here? If it is hardy, how can I get my hands on one? I’ve planted several apricot trees over the years, but never harvested a single fruit ever.

Blenheim of which it is a sport is not considered winter hardy.

In my experience zone pushing works generally when there is some cultivar known for success and then you graft and experiment to try to build on that success. You are certainly welcome to try, I can send you some scion next year.

You may have already tried these things:

Microclimate - if you can place your apricots on an elevated portion of your yard (such that cold morning air drains away) and facing east (so that cold morning air warms up first) this mitigates frost damage. In my completely different climate this approach enabled me to grow some tropical fruit that had been decimated when planted in the low areas.

Cultivar - Find out what works for people in similar zones. I know of Hoyt Montrose, which was successfully grown in Colorado and has a nice history to it.

I think apricots are a real challenge for the coldest zones, other than in greenhouses. Search for the word “Colorado” and there are a lot of interesting chains on others’ attempts. Good luck!

Interesting info on Steindorf Blenheim. I should try it next year. I really like Blenheim and this can extend the harvest season. I have grafted Red Sweet and Losse Blenheim this year. Any info on Losse? I can’t seem to find much online - aka how is this different from (Shipley’s) Blenheim?

I am grafting cherry cox this year. I am also grafting it’s parent - cox’s orange pippin which is a notorious low vigor apple. Will be interesting to compare the 2 side by side in my climate.

Cherry Cox Apple Variety and a Few Others, Tasting and Review — SkillCult

As a side note…I am thinking of grafting cox’s orange pippin on my most vigorous seedling rootstock from last year (grew 4 ft. It’s first year in my short growing season) to see if it puts a little pep in it’s step…

You asked about Losse Blenheim. C Todd Kennedy said in a talk in 2018 at Festival of Fruit that Shipley’s Blenheim is not productive every year and Losse Blenheim is. He said that they were used interchangeably by nurseries in the 1930s. If that is correct then Losse may be a common strain today but not identified as such.

If this is true then identifying the genetic difference between Losse and Shipley would be of interest!

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I got the budwood from @Stan. I am sure he read many old books, traced various sources, correctly identified and grafted all the different Blenheims :wink: More reliable than ARS-GRIN! Meanwhile, I just have to drive up to Tracy :smiley:

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What! I’m at a loss as to why this variety isn’t available as a frost safe apricot and isn’t used as a breeding tree to create varieties for more northern areas.

Hard to believe.

if seen more often than not that claims about a sport’s attributes are overly exaggerated.
30 days later flowering seems extreme. Or might be only in verry specific circumstances. (early slight heatwave that just wakes up belnheim and just not wakes up the steindorf) followed by cold weather.

If true in most circumstances though 30 days delayed flowering sounds awesome on an apricot!!

@JamesN Did it reliably flower 30 days later for you? And only in 1 year? or most years?
even if the 30 days is exaggerated, a week is also quite amazing :slight_smile:

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There is definitely a distinction between validity in its original location, and universal translateability to different locations. I don’t think we are (intentionally) claiming the latter. My understanding is you all tend to see more compressed bloom. Where I am, stone fruit bloom (in general) starts in December, and ends in mid-May.

Here is what Mr. Steindorf said in the original patent from 1967:
“My new discovery relates to a new and distinct variety of apricot or Prunus armeniaca, originating as a sport of the parent variety, Blenheim apricot, and is characterized by its habit of blooming and bearing approximately thirty days later than the parent Blenheim apricot.”

There are 3 reasons why something might flower later:
-higher chill requirement
-different photoperiod sensing
-heat responsive in growth

Steindorf Blenheim definitely shows no evidence of a change in heat responsivity, and in So Cal, I would recognize it!

I grow Steindorf in two locations:
Inland southern California
Bay Area (where I grew up)

It does flower about a month late in both locations. In the Bay Area, my observations are less direct, I am up there a lot but not constantly. I was there April 14 and it was mostly done but it did have some flowers still. That puts it about a month later than Blenheim in that location.

In San Diego, Blenheim started the final days of February and Steindorf started the first week of April. Just over 30 days.

My guess is it is just a high chill Blenheim, and there is not going to be anything unique about the cultivar in your higher chill area. Going along with my higher chill theory:

-seems to struggle in terms of chill in my location. Blenheim does have scattered bloom also but fruits abundantly every year. Steindorf is like a totally different creation.
-I have a small specimen grafted in eastern shade and its bloom was actually more compact, and a bit earlier than the big tree, suggesting it met its chill requirements earlier and better in the morning shade.
-If Blenheim has some high chill factors in its heritage it would make sense that a sport mutation could unmask them and create later flowering. I assume bud sport mutations don’t generally create new functions, but disrupt functions, leading to the unmasking of hidden (recessive gene) traits?

The one thing that made me wonder about this cultivar is to me it tasted like Moorpark. In San Diego, it flowers and fruits synchronously (and meagerly) with Moorpark. I questioned whether I was able to finely discriminate apricot flavors and then I saw Andy Mariani describes Steindorf as having a Moorpark flavor. Maybe that is how Blenheim tastes if it gets another month of sun and heat to make those flavors more plum-like and floral.

Let’s see if we can get @Stan to comment since he is in a higher chill area than the south bay. If Steindorf is just a high chill Blenheim then he would probably see it flower earlier, closer to Blenheim. He would also be able to differentiate it better from Moorpark, since that is his favorite cultivar (or was).

Finally, if anyone wants to try this next year let me know and I will send scion. I will be hacking it back this winter and using the tree more for testing new varieties.


Thanks for the detailed reply :heart: thats awesome :grin:

Unfortunatly if it’s just a high chill version, it would make it only valueble to places that are on that chill requirement border. And mostly maratime/stable climate regions.

As far as i understood it they are basicaly mutants. They can have different phenotypes by many mechanisems (damage to dominant gene and thus expressing recesive gene. But could also alter gene’s to act differently. Or alter the expression “amount” of gene’s) So im not sure, but i think they don’t only unmask recessive genes.

From what i understood, most bud mutations happen either by chance due to copying errors during the formation of the buds. Or are most often from latent buds that recieved UV radiation for years, And then sprouted due to heavy pruning. After heavily pruning back an older tree you’r most likely to encounter sports.

I lost the tree on which Steindorf Blenheim was grafted, so I only had a couple of years to observe it. At my location it bloomed at most a week after Bleinheim. However, they were grafted on different trees with different rootstocks, so it’s not a completely accurate comparison.

They would bloom at the same time, or maybe with a one day difference, in your location. At my place, Zard blooms one month after Tomcot, while at @mamuang’s the difference is hardly a week. Additionally, high-chill varieties can bloom very late in low-chill locations like Bay Area or San Diego. I see reports from people in such areas about their trees blooming when for me these varieties finished blooming a month or month and a half earlier. Blooming times in these areas have zero relationship to what you would see up north.


You’re right. When I saw that @JamesN is in zone 9, I thought the vast difference of bloom time of one variety to the next was very possible. It is not just stone fruit. We have known about pears, too.

In colder climate like mine. Pears bloom time mostly overlaps one another. I have over 20 + varieties of pears (both Asian and Euro).

Zard blooms about 5-7 days later. That could make a difference. However, Zard did not set well for me so if I were to choose between Zard and Tomcot (where I am), I will choose Tomcot every time. It tastes good. It has a longer bloom time and sets like mad. Some blooms on Tomcot are likely to escape freeze and produce fruit.

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