Triploid apples

[boundtothesoil]

After reading what's been said by FB and orangepippin about triploids in this topic, I looked at the records for the crosses I've made between 2010-2013 to see how different varieties performed in terms of success of failure when used as either female or male parents. I've listed the results below separately for female and male parents. I would have pasted in a nice bar chart graph, which is much clearer, but the file size was far too large to be accepted.

The sample size isn't very large and none of the results are statistically robust, but a few indications might be of interest viz a viz the variations on tripoidy mentioned by Orangepippin.

Each 'cross' consisted of a single cluster of three emasculated (female) flowers hand pollinated with pollen from a cluster of covered flowers (i.e. preventing pollen contamination) from the variety selected as the male parent. 'Success' was defined as at least one of the three pollinated flowers producing a mature apple with at least one fully developed pip inside it. 'Failures' were subdivided into 'failed pollination' (i.e. the flower dropped off) and failure post pollination (i.e. developing fruitlet dropped off in June drop or later.). I haven't listed the actual crosses, although generally I tried to avoid using self fertile varieties as female parents after the first year or so and there are not many duplicates.

Female parents Nos crosses, Nos successes, Nos failed pollination, Nos failed post pollination
Adam’s Pearmain 6 1 5 0
Annie Elizabeth 5 0 5 0
Ashmead’s Kernel 8 2 4 3
Beauty of Bath 20 13 1 6
Bramley’s 6 2 3 1
Cox’s Pomona 1 1 0 0
Discovery 23 16 5 2
Ellison's Orange 19 9 0 10
Emneth Early 1 1 0 0
George Cave 14 6 6 2
Grenadier 4 1 1 2
Ida Red 10 6 1 3
James Grieve 6 3 2 1
Katy 4 2 0 2
Lord Lambourne 10 9 0 1
Scarlet Pimpernel 6 2 4 0
Spartan 8 7 0 1
Sunset 9 2 5 2
Winston 2 1 0 1
Tydeman’s late Orange 1 1 0 0
Totals 163 84 42 37

Male parents Nos crosses, Nos successes, Nos failed pollination, Nos failed post pollination.
Adam’s Pearmain 12 7 1 4
Annie Elizabeth 5 1 3 1
Ashmead’s Kernel 0 0 0 0
Baker’s Delicious 4 2 1 1
Beauty of Bath 12 1 4 7
Braeburn 4 2 1 1
Cox’s Pomona 4 2 1 1
Discovery 1 1 0 0
Egremont Russet 9 6 2 1
Ellisons orange 10 6 4 0
Emneth Early 2 1 1 0
George cave 4 3 1 0
Grenadier 2 2 0 0
Gwell Na Mil 6 5 1 0
Honeycrisp 5 4 0 1
Ida red 4 2 1 1
James Grieve 13 10 2 1
Katy 8 4 1 3
Lady Lambourne 3 1 1 1
Llanerchaeron Beauty 4 3 0 1
Lord lambourne 3 2 0 1
Monmouth Beauty 5 3 1 1
Scarlet Pimpernel 20 9 4 7
Spartan 7 4 2 1
Sunset 7 3 2 2
Tydeman’s Late orange 5 3 1 1
Total 159 87 35 37


The most interesting things about the numbers in the context of this thread are how useless Annie Elizabeth has been and how Adam's Pearmain has been a dud female parent for me, but quite a successful male parent. Hence, I'm querying a strait triploid status for Adam's Pearmain.

The other thing I find odd is how Beauty of Bath is a pretty good female parent, but a useless male parent, even though it has great looking pollen. Lastly, Sunset has been pretty rubbish all round so far.

[boundtothesoil]

-

How many of the fine triploid varieties still being grown have produced lots of good seedlings?
Not many.

Why?
Probably because the abnormal genetics of triploids (which makes them poor pollinators of others) probably means genetic abnormalities in the offspring produced from those same triploids (abnormal pips/seeds) which would be expected to result in a very low proportion of high-quality seeds and lots of low-quality seeds.

I have just got some results from germination of pips from crosses made in 2013 that illustrate FB's point. The photo shows three sets of seedlings:-
1. Open pollinated Annie Elizabeth: 39 pips sown; 19 seedlings emerged ( 49% germination).
2. Open pollinated Ashmead's Kernel: 45 pips sown: 24 seedlings emerged (53% germination).
3. Beauty of Bath x Lord Lambourne crossed: 10 pips sown: 10 seedlings emerged (100% germination).



All the pips were sown at the same time and treated similarly.

Apart from the higher germination rate of the diploid cross (Beauty of Bath x Lord Lambourne) compared with the triploid (Ashmead's Kernel) and the probable 'odd-ball' ploid (Annie Elizabeth ), the most obvious difference is in uniformity of seedlings. The diploid cross seedlings look pretty uniform, but there is wide variation in the phenotypes of the Ashmead's Kernel and Annie Elizabeth offspring. These include stunted types, three-cotyledon types, mottled cotyledon types, and deformed cotyledon types. They also had a much wider range of emergence dates compared with the diploid cross. I doubt that some of these triploid offspring will make it to the first true leaf stage of developement.

[digon]

I also planted some crosses from 2013 and had a massive diiference in germination rates.
I crossed the following:
Pitmaston pineapple female x Redlove Era male......100% germination within 8 days of planting. (14 from 14)
Redlove Era female x Scrumptious male.......zero germination 5 weeks after planting. (0 from 28)

Despite the seeds being handled, stored and planted exactly the same ie. 3months at 2degC I thought the Era seeds must have perished somehow but now having re-read this thread, maybe Redlove Era is a Triploid? It does have large course edged leaves and is very vigorous but the fruit also had a large number of perfect looking seeds.

[boundtothesoil]

maybe Redlove Era is a Triploid?

Interesting results. I have no knowledge of Redlove Era, but I don't think it can be a triploid because it has worked so well for you when used as a male parent (hence likely diploid). I have very rarely if ever had any successes using pollen from triploid varieties in crosses, and I've tried quite a few.

I'm intrigued that you have crossed Pitmaston Pineapple. It's on my list of to do crosses but I haven't had any flowers on my two year old Pitmaston Pineapple grafted tree to use.

[digon]

Interesting results. I have no knowledge of Redlove Era, but I don't think it can be a triploid because it has worked so well for you when used as a male parent (hence likely diploid). I have very rarely if ever had any successes using pollen from triploid varieties in crosses, and I've tried quite a few.

So it does sound as though the seed has perished during storage.
I'll try again this year and see what happens.
Do you bag the emasculated female flowers to prevent natural pollination?

[boundtothesoil]

Do you bag the emasculated female flowers to prevent natural pollination?

Yes, I select three flowers per cluster at the balloon stage, emasculate them then immediately protect them in small muslin bags. I pollinate them when they have opened, brushing them with depetalled flowers I have previously identified as my 'male parents' also enclosed in muslin bags at the balloon stage to prevent any pollen contamination. I leave the muslin bags on the pollinated female flowers until the fruitlets start to expand. This is probably a bit of an over zealous approach, but I am keen to maximise the chances that the cross I want to make is the one that I get. For this reason, I try not to use proven/listed self fertile varieties as the female parent, unless I'm trying to cross two self fertile ones.

[FB.]

Redlove Era female x Scrumptious male.......zero germination 5 weeks after planting. (0 from 28)

Try the same cross again, but use the same batch of Scrumptious pollen that you use on the Redlove to pollinate several other non-triploid varieties. Then check seed germination from all crosses with Scrumptious as a father.
Also try Redlove as a pollinator for Scrumptious. Maybe some kind of incompatibility mechanism makes the seeds non-viable due to varieties being related; Redlove has red flesh, as does the mother of Scrumptious; Discovery to a limited extent, as does the 'sport' of Discovery called 'Rosette'. So maybe they are related and inbreeding is the problem.

It is possible that Scrumptious might be triploid or nearly triploid and although capable of pollinating the flowers and pips being produced in other varieties, there may be sufficient genetic abnormalities in the pips that they don't germinate.

I have never managed to germinate a pip from Crawley Beauty despite it producing lots of good-looking pips - and its good disease resistance and tolerance of difficult soils (such as chalk) might be indicators that it is triploid.
I also noted in a previous topic that many triploids were once listed as self-fertile (Crawley Beauty is self-fertile) and that many varieties - often 'cookers' - I suspect to be triploid (but which haven't been scientifically proven) are listed as self-fertile (e.g. Annie Elizabeth, Lord Derby, Grenadier etc).