Project Summaries

11-895  Project Manager: D. C. Jones

TOWARD AN EXOTIC NESTED ASSOCIATION MAPPING POPULATION SET FOR UPLAND COTTON

Andrew H. Paterson, University of Georgia

For 2012, we proposed the following activities: 1)  To continue 'generation advance' for a set of 24 "exotic NAM" populations that we have begun to develop, crossing each of 12 selected race stocks to both Acala Maxxa and DES 56; and 2) To corroborate anticipated genetic relationships among these lines, try to identify genomic regions implicated in short-day versus day-neutral flowering, and identify DNA polymorphism suitable for genetic mapping.

In 2010, we produced many crosses for a total of 32 F1 combinations of converted race stocks to Acala Maxxa and/or DES 56, also conducting DNA marker genotyping to confirm hybridity (and weed out false positives) that were sent to Tecoman and planted for production of F2 and backcross seed. In addition, we have F1 plants for 21 previously-made converted x elite crosses and a cross between the elite parents in the growth chamber now, having collected about 2,000 seed to date (averaging about 100 per cross) and still collecting seed. Plants from more than 2,000 F2 seed grown here in GA last year (complementing those sent to Tecoman), were selfed last year and short F3 progeny rows are in the field for another generation advance this year. On a subset, we intend to also collect limited phenotypic information for quantitative genetic evaluation and possibly exploratory QTL mapping.

Although not originally proposed, we also have made backcrosses (to DES 56) for a subset of F1 crosses that broadly sample the cotton botanical races, to permit early exploration for transgressive alleles and expedite their transfer to adapted germplasm. One backcross to DES56, for one representative of most of the botanical races, was sent to Tecoman for advance, and we have planted BC1F2 plots of about 100-150 plants from seven of these populations for evaluation here in Georgia in summer 2012. Fiber has been harvested and is being processed for fiber analysis. Tissue was sampled and DNA extracted, toward exploratory genetic mapping.

We have completed the lab work for a screen of ~700 SSRs on the exotic/converted pairs, and elite parental lines, providing both DNA polymorphism for mapping and information about the genomic distribution of 'conversion' (introgression of day-neutral flowering) in this diverse sampling of germplasm. Analysis of the data is in progress, with a preliminary report presented in the 'Marker-Assisted Selection' workshop at PAG.

As an aside, we note that under our current NSF-funded cotton project, we have tentatively plotted the probable locations in the first genome assembly of virtually ALL DNA markers in CMD. This work was presented in a talk by Zining Wang at PAG in 2012. We intend to publish the resource promptly, although must respect the "Ft Lauderdale rights reserved by the JGI (http://www.phytozome.net/cotton.php#C3) to defer publication of whole-genome analyses until after the genome sequence is published.

 

Project Year: 2012
 

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