Provisional Identification of Wheat Genebank Accessions
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Contents |
Introduction
The identification of accessions started with the current list of genebank samples identified by an introduction number (INTRID) and a CID, SID combination.
A set of 163581 distinct combinations of INTRID, CID, SID was extracted from the list of samples. 98859 of these are associated with CID, SID combinations with SID<>0, the rest, 64722, have SID=0.
IWIS2 Selections identified with Accessions (SID<>0)
For distinct CID, SID combinations with SID<>0, it was assumed that each represents a single genotype, either an imported line or a CIMMYT breeding line. 15165 of these have INTRIDs with donor or collection information in the SQL Server WGB database (tables WGBPassport and WGBCollection). These were treated as separate accessions. New germplasm records having the record corresponding to the CID SID combination as source, but having their CID and SID fields zero, were added to form the founding germplasm for these accessions. The remaining 83698 cases with SID<>0 had no collection or donor information. These were grouped into 62628 distinct CID, SID combinations. Each of these was treated as an accession with one or more INTRIDs. A single INTRID for each of these putative accessions was selected from the sample information by taking the one from the earliest-trial, with the lowest trial ID and lowest entry ID. This was assigned as the Accession Name to the original record with the CID, SID combination while other INTRIDs were assigned to the same record as Alternative Accessions Names.
IWIS2 Crosses identified with Accessions (SID=0)
The 64722 combinations with SID=0 fall into three classes:
- Introduced lines with known parents (6628). These are identified in IWIS2 by having no BCID or having BCID not recognized as a CIMMYT Cross and are assumed to be improved lines.
- Introduced lines with unknown parents (57157). These can he assumed, at a first cut, to be landrace collections or wild species.
- CIMMYT crosses (with BCID and known parents) (937).
In the first case, 190 records appeared as foreign crosses with accession numbers. These were split into a cross record and the existing record changed to a derivative from that cross with unknown source. The INTRIDs were added to the existing record as Accession names. The remaining cases were treated like germplasm having SID=0 as described above (2739 with unique INTRIDs, and 3699 with multiple but distinct INTRIDs).
In the second case, if there was only one INTRID associated with the CID, it was assigned to the existing record as Accession Name (49889). Otherwise, new germplasm records were added for each distinct INTRID related by group (GPID1) but not source (GPID2) to the existing record with CID=0, SID=0 and having preferred NAME equal to the preferred name of the group with suffix ‘– INT’. The INTRIDs were added as Accessions Names (7268).
In the third case, a small number of germplasm were identified as complex interspecific crosses or experimental crosses where F1s are lodged in the bank (493). For the rest (444) it was assumed that these introductions corresponded to unknown lines derived from the CIMMYT cross. New germplasm records were added for each INTRID with group (GPID1) equal to the cross record and preferred name equal to the cross name with suffix – INT. The INTRIDs were added as Accession Names to these germplasm.
The resulting list of Accessions
The final classification of the 141082 distinct accessions identified by this process is: Sample Records for the Wheat Germplasm Bank.
| Germplasm Class | Count |
|---|---|
| F1s from CIMMYT crosses | 493 |
| Imported lines with unknown derivative group | 19335 |
| Imported lines with unknown group or source | 49889 |
| Lines from CIMMYT crosses | 63082 |
| Lines from non-CIMMYT crosses | 8283 |
| Total | 141082 |
With the founding germplasm for each accession defined in the central database germplasm records were added for each of the 603833 seed samples to the IWIS3-WGB Local database. The group (GPID1) links to the group of the founding germplasm and the Management Group (MGID) links to the GID of the founding germplasm. Each sample has a trial (TID) and Entry Number (ENT) indicating the plot from when the sample was harvested and Sample Names were constructed as INTRID: TID ENT for each germplasm record.
IWIS3 Representation of Germplasm Samples
Many samples have source trial (STID) and source entry (SENT) also identified. For a given sample, A, if the STID and SENT values match the TID, ENT values for sample B, then the germplasm source (GPID2) of sample A is set to the GID of sample B. If the source trial and entry did not exist in the samples list (presumably because the trial was conducted outside of genebank activities) then germplasm records were added for those sources having the same germplasm group as the sample and Plot Name constructed as STID SENT. The germplasm sources (GPID2) of the dependent samples were linked to these records.
