Genetic assessment of a mini-core subset developed from the USDA rice genebank

H. A. Agrama, Wen Gui Yan, Fleet Lee, Fjellstrom Robert, Ming Hsuan Chen, Melissa Jia, Anna McClung

Research output: Contribution to journalArticlepeer-review

121 Citations (Scopus)


Development of core collections is an effective tool to extensively characterize large germplasm collections, and the use of a mini-core subsampling strategy further increases the effectiveness of genetic diversity analysis at detailed phenotype and molecular levels. We report the formation of a mini-core subset containing 217 entries derived from 1794 core entries representing the genetic diversity found in more than 18,000 accessions of the USDA-ARS rice (Oryza sativa L.) germplasm collection. The mini-core was developed with PowerCore software on the basis of 26 phenotypic traits and 70 molecular markers. The 217 entries in the mini-core had a similar distribution over 15 geographical regions, with 1794 entries in the original core collection. The resultant mini-core had 6.3% of mean difference (MD%), 16.5% of variance difference (VD%), 102.7% of variable rate (VR%), and 97.5% of coincidence rate (CR%) with the core collection, which brought about full coverage of 26 traits. All 962 alleles identifi ed by the 70 markers in the core collection were captured in the mini-core, which maximized allelic richness up to 100% and resulted in an average genetic diversity (Nei index) of 0.76, ranging from 0.37 to 0.97 among the markers. In conclusion, the mini-core presented in this study is a highly suitable and representative subset of the USDA rice core collection as well as the entire USDA-ARS rice germplasm holdings.

Original languageEnglish
Pages (from-to)1336-1346
Number of pages11
JournalCrop Science
Issue number4
Publication statusPublished - Jul 2009
Externally publishedYes


  • ASV
  • Alkali spreading value
  • CR%
  • Coincidence rate
  • MD%
  • Mean difference
  • PCR
  • Polymerase chain reaction
  • QTL
  • Quantitative trait loci
  • SNP
  • SSR
  • Simple sequence repeat
  • Single nucleotide polymorphism
  • VD%
  • VR%
  • Variable rate
  • Variance difference

ASJC Scopus subject areas

  • Agronomy and Crop Science


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