Apple ID using SSR pear marker-pairs – an investigation

Confidence that two varieties, Cherry Pearmain and Skyrme’s Kernel, are indeed different was a major spur in developing this research study.

These varieties have subtly different morphology, but substantially more different blossom and leaf opening times, taste and tree habit.  There is only one difference in the apple SSR fingerprints in the second allele of CH01f03b being 162 vs 136.  Details have been described in the accreditation Registration Request Evidences for them.

Dr Danny Thorogood of IBERS was asked by Museum of Cider to test further the fingerprint difference by running samples with the standard set of pear marker-pairs, of which only GD147 is common with apples.

Several marker-pairs were found to have differences in excess of 2bp and are discussed in the section on Cherry Pearmain and Skyrme’s Kernel below.

Two benefits were seen.  As above it could provide additional SSRs with which to assess whether two (similar) fingerprints were indeed the same or different.  And in assessing a parentage and progeny relationship, the additional SSRs would increase its confidence.

In total 37 samples were analysed including another case of two very similar varieties and several where the additional data supported, or refuted, possible parentage.  A report is available here.