"Settled Science", 1900s edition (Long, Geek alert)

Between 1880 and 1920, plant breeding was HUGE business. They named cities after plant breeders (Burbank, Ca. Hazen, N.D.). It was a very big deal.

Wealthy apple. Plants from the mid-West tend to be have a lot more red.

At the beginning of that same timeframe Peter Gideon, an apple breeder near Lake Minnetonka, Minnesota released the Wealthy Apple. He reported the pedigree as Sops-of-Wine and "Cherry Crab" which was a generic name given to a swarm of similar Malus X robusta  hybrid crabapples.

Gideon went on to be the head of the apple-breeding effort in Excelsior. That venture, which was associated with the University of Minnesota went on to release about 30 apple varieties including the Honeycrisp apple. 

The story

Breeders typically report the parents of the apple they release. Unless they are using mass-breeding techniques, that isn't too hard to do. The breeder (or his grad students) bag unopened apple blossoms. When they open, they gently move pollen from the flower of the chosen male parent to the pistil of the female parent. The bag is replaced and they move on to the next bunch of blossoms. Typically, a colored twist-tie will be used to identify the male parent.

As a percentage of seedlings planted, what do you suppose the "misidentification rate" be? Consider that sometimes blocks of seedlings might get intermingled. 1%? 5%? 20%? 0.01%?

The majority of the data cited in this post came from this article

DNA testing suggests that the failure rate might be enormous.

Cultivar	Year Introduced	Reported Pedigree	DNA Pedigree
Wealthy	1868	Sops-of-Wine X Cherry Crab	Jonathan x Dutchess*
Haralson	1922	Malinda open-pollinated	Malinda x Wealthy**
Wedge	1921	Ben Davis open-pollinated	(Malinda x Duchess) X Northwest Greening
Folwell	1921	Malinda open-pollinated	Duchess x (Alexander x Golden Russet)
Chestnut	1949	Malinda open-pollinated	Wealthy x (Kewick Codlin x Ukn.)
Minnehaha	1920	Malinda open-pollinated	Wealthy x (Ben Davis x Snow)
Victory	1943	McIntosh open-pollinated	McIntosh x Wealthy
Beacon	1936	Malinda open-pollinated***	(Malinda x Duchess) x (Malinda x Tetofsky)
Frostbite	2008	Unknown	(Duchess x Utter’s Large Red) x Ukn.
Redwell	1946	Scott Winter open-pollinated	Wealthy x (Alexander x Ukn.)
Minjon	1942	Unknown	Wealthy x Malinda
Oriole	1949	Unknown	Wealthy x Ukn.
Lakeland	1950	Malinda open-pollinated	Wealthy x Malinda
Fireside	1943	Unknown	Wealthy x Northwest Greening
Prairie Spy	1940	Unknown	Wealthy x Northwest Greening
Northland	1957	McIntosh x Dolgo	McIntosh x Dolgo
Regent	1964	Duchess x Red Delicious	Harlason x McIntosh
Centennial	1957	Dolgo x Wealthy	Dolgo x Chestnut
Red Baron	1970	Duchess x Golden Delicious	Duchess x Golden Delicious
Keepsake	1978	Frostbite x Northern Spy	Frostbite x Northern Spy
Honeygold	1970	Golden Delicious x Haralson	Golden Delicious x Haralson
Sweet Sixteen	1977	Frostbite x Northern Spy	Frostbite x Northern Spy
State Fair	1977	Mantet x Oriole	Mantet x Haralson
Honeycrisp	1991	Macoun x Honeygold	Keepsake x (Duchess x Golden Delicious)
Wildung	2006	Fireside x Sharon	Fireside x Sharon
Minnewashta	1998	State Fair x MN1691	State Fair x MN1691
Minneiska	2006	Honeycrisp x Minnewashta	Honeycrisp x Minnewashta
MN55	2016	Honeycrisp AA44	Honeycrisp x AA44
MN80	2021	Honeycrisp x Liberty	Honeycrisp x Liberty

DNA evidence suggests that eleven of the twenty-eight releases (almost 40%) were reported to have pedigrees that DNA testing disproved.

Those disproved pedigrees are in the Bold Red font and Pink font in the reported pedigree column. 

Wealthy, shown in Bold Green font shows up in far more crosses than it was credited with. How could that happen?

Malinda apple

Suppose you are a grad student and one of the projects you have been assigned is to produce 100 seeds of Malinda (which shows up in many pedigrees) crossed  by Ben Davis (a fairly disease resistant apple). You figure that you will get 5 seeds per apple so you pollinate the "king blossom" in twenty clusters and call it good.

When it is time to harvest the apples you can only find five good apples. What do you do? You make up the difference with apples from the tree next to it! One thing I remember about Wealthy apples is that they can sit on the ground for weeks and not be rotten.

Or maybe  the row of Malinda the five trees in that were closest to the lane were actually Wealthy. Or maybe the professor leading the breeding was intentionally misinforming his competitors regarding the pedigrees of his "home runs".

Why this information might matter

Old-time breeding programs tested very few seeds because of the expense of raising a tree to fruiting. While a program in 1920 might think 100 seeds of a cross was plenty, modern programs can easily rip through 100,000 seedlings. That much larger number allows the researchers to find and select for mutually-reinforcing recessive genes and for interactions between genes.

The modern researcher gets around the economics by culling at incredible rates while the seedlings are still tiny. They can cull for phytophthoria before the seedling has its first true leaves. They can cull for fireblight resistance at three weeks of age. They can cull for cold hardiness at eight weeks of age.

They test for phytophthoria by submerging the emerging seedlings in water that has been inoculated with several strains of the causal agent for collar-rot and letting them sit for a week. 

They test for fireblight by running a sand-blaster to expose growing tissue beneath the bark and spraying the injured seedlings with a solution with three-to-five strains of the most virulent strains of fireblight.

They can test for coldhardiness by putting the survivors into a chiller set at 30F for two days to acclimate them, then by submerging the above-ground stems into a slurry of antifreeze-and-water at -40.

Tough? You darned betchya!  But it is extremely economical compared to releasing a variety and having farmers plant hundreds of acres of it only to have it collapse due to some biotic or climate stress.

So, just scanning through the list of what was released, if I were a betting man I would do a remake on the Wealthy x Northwest Greening and use modern, intensive culling techniques to see what happened.

* Published articles claim Wealthy is Jonathan x Duchess. I pulled the SSRI data from the ARS/GRIN website for those three apples. The Jonathan is a solid match. The data for Duchess is not. One of the issues that can happen with Heritage/old apples is that there can be a swarm of seedlings that have been marketed as "Duchess" and it is possible that the sample pulled for the ARS/GRIN SSRI data was not the Duchess used by the breeder who created Wealthy.

**Convention lists the maternal/seed parent as the first in a cross with the paternal/pollen parent second. In mammals, it is possible to determine which was the maternal parent based on the RNA in the mitochondria. That RNA is not present in the sperm. In plants (to the best of my knowledge) it is not possible to determine which parent was maternal and which was paternal.

***Listed in pink because neither parent was actually Malinda. They may have been tentatively labeled "Improved Malinda" but that is just one more way things can go south in the breeding orchard.