Triploid Fruit Trees

[yummersetter]

Because I'm new to your writings, could you explain the numbers after the varieties?

[FB.]

Because I'm new to your writings, could you explain the numbers after the varieties?

They refer to incompatibility groups. Varieties with the same pair of numbers will be almost entirely incompatible. Varieties with one number the same will be partly incompatible. Different numbers would be fully compatible.

So you can see that Worcester Pearmain (2,24) was crossed with Beauty of Bath (1,4) and created Discovery (1,24; 1 from Beauty of Bath and 24 from Worcester).

[orangepippin]

Some time ago FB pointed me towards the apple incompatibility data, and we then incorporated it in our online pollination checker. The latest version now uses flowering groups, parentage, and incompatibility data to provide a hopefully accurate list of suitable pollinators for any given apple variety.

[yummersetter]

Your website has become a great resource, OP, thanks for all your hard work.
Still thinking about the incompatability group list. Is there more information on here?

[FB.]

Your website has become a great resource, OP, thanks for all your hard work.
Still thinking about the incompatability group list. Is there more information on here?

Incompatibility groups is not really an issue with apples. If the varieties aren't related then there is unlikely to be a problem.

The whole incompatibility system is a natural mechanism to reduce inbreeding and promote outcrossing.
It works by detecting pollen carrying a certain incompatibility gene; the flowers destroy pollen labelled with the same incompatibility gene as in the flowers own genetic makeup on the assumption that the pollen is its own.
So Discovery's "1" allele (inherited from Beauty of Bath: 1,4) will be rejected by Beauty of Bath, but its "24" allele (inherited from Worcester Pearmain: 2,24) will be accepted by Beauty of Bath.
So Discovery would be 50% effective as a pollinator for Beauty of Bath.
Similarly; Discovery's "24" allele would be rejected by Worcester Pearmain.

But throw in Cox (5,9) and Cox's pollen will be eagerly accepted by the flowers of all three above-mentioned varieties.

To save me typing out a long waffle about inbreeding, an apple enthusiast has had their little rant about modern varieties being inbred and losing their health and vigour as a result:
Inbreeding/genetic narrowing in modern apple cultivation, DIVERSITY website

With pears - and especially cherries - incompatibility groups can become a major headache. Some cherries require a specific variety as a partner in order to set a crop.

[yummersetter]

Thank you. Another interesting article. I'm unlikely to ever plant more than a couple more apple trees, but enjoy learning more about them.
So might my Redsleeves, (also Worcester Pearmain x Beauty of Bath) have the same allele combination as Discovery or could it be, say, 2,4 and compatible? (this may be revealing my ignorance of alleles at the moment).
Also, with regard to pollination, is there any difference in reward to the pollinating insects between triploid and diploid nectar and pollen? Apart from the size of the trees, triploids being more vigorous tend to have more flowers per tree so a bee can fill up their pollen sacs more efficiently, does, for example, the triploid flower produce more protein or sugars?

[FB.]

Thank you. Another interesting article. I'm unlikely to ever plant more than a couple more apple trees, but enjoy learning more about them.
So might my Redsleeves, (also Worcester Pearmain x Beauty of Bath) have the same allele combination as Discovery or could it be, say, 2,4 and compatible? (this may be revealing my ignorance of alleles at the moment).
Also, with regard to pollination, is there any difference in reward to the pollinating insects between triploid and diploid nectar and pollen? Apart from the size of the trees, triploids being more vigorous tend to have more flowers per tree so a bee can fill up their pollen sacs more efficiently, does, for example, the triploid flower produce more protein or sugars?

edit:
I just looked up the ancestry of Redsleeves and its grandparents on one side are Worcester x Beauty of Bath which gave Exeter Cross.
On the other side of the family are some un-named research varieties.


If Exeter Cross was Worcester x Beauty of Bath, it could be:
1,2
1,24
2,4
4,24

(or it might possibly even be triploid or tetraploid and we don't know it!)

So, there's a small (25%) chance that Exeter Cross would be 2,4 and therefore fully compatible with Discovery 1,24.
There's a 25% chance that they'd both be 1,24.
...and a 50% chance that they'll share one but not both; therefore only partially compatible.

But then Exeter Cross was crossed with an un-named and unknown-compatibility variety in order to create Redsleeves.
So we're really starting to take a wild guess as to what ended up in Redsleeves.
Redsleeves will be carrying one of the four incompatibilty alleles from either Worcester or Bath grandparents, but we have no idea what is on the other side of its family.

As for diploid v triploid in terms of what the bees prefer: I can't imagine there'd be a significant difference.
But if both a diploid and a triploid were to produce the same number of flowers, the often-slightly-larger fruit of a triploid would not require such high pollination rate to produce the same weight of fruit (because a Bramley apple is perhaps twice the size of a Golden Delicious apple - but both would be the product of one flower).

[yummersetter]

Walking round the apple orchards and looking at the first green leaves breaking out of the buds I noticed that all the early risers (except Rev Wilkes) are triploids