OHxF Pear Rootstock is actually OHxBartlett?

General Fruit Growing
1

I had seen references to this in at least one thread but saw none clarifying it as it’s own topic.

I don’t think we’ll see a change in name, but the irony is there…

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2

@disc4tw
The article you found is from the December 2013 issue of Good Fruit Grower. The research mentioned is from Bassil & Postman 2010 - Identification of European and Asian pears using EST-SSRs from Pyrus . This methodology has been proven very faulty. In particular, the PCR annealing process produces marker responses even when the markers are not present in the DNA. As a result, Dr. Bassil is now reassessing the prior work using SNP transcriptomes.

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Thanks for sharing @Richard. I am no geneticist so input is welcome and encouraged.

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It’s my understanding the SNP data confirmed the original findings. At least that is what Dr. Bassil says at the 18:40 mark of this seminar talk:

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Thanks for sharing - I didn’t realize how important White Doyenne is to all the Euro pear variteies

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@Everett,
That presentation is from her 2020 SNP paper, not the 2010 paper mentioned in post #2 above.

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Here is the 2020 paper.
Zurn et al 2020 - A new SSR fingerprinting set and its comparison to existing SSR-and SNP-based genotyping platforms to manage Pyrus germplasm resources.pdf (888.1 KB)

The SNP’s in this study have yet to be verified in chromatin DNA sequences of the specimens under study. Consequently the values they report could just be anomalies of the PCR device – a known phenomenon. Further, the genomics analysis did not use metric distance measures and thus all values are questionable. I spoke to her about it this summer in relation to their work with Rubus.

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Thanks for sharing - after initial fingerprinting, they could not distinguish Sheldon from Anjou, and Colette from Beierschmitt

fingerprint

It is not clear if the Germplasm has them mislabeled or they are indistinguishable by SSR

error

I grafted Sheldon and Anjou to Callery and should be able to tell once they start fruiting

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… or indistinguishable by the choice of dissimilarity measure.

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I assume similarly to statistics, performing the correct test and interpreting the data properly is very important. Probably as important as getting good samples etc.

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I think Joseph Postman talked about this at our last Home Orchard Society annual meeting. I think it meant there is still untapped potential from including Farmingdale genetics to improve rootstock.

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@disc4tw
The greatest problem here is the public confusion with genetic sequencing and genetic markers. The latter does not include the former.

The second problem is the reliance of many horticultural researchers on claims made by manufacturers of PCR assay hardware. The faulty nature of these claims is now being exposed by advances in genome sequencing.

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