Project Summary

This Rice Plantproject will test a multi-faceted strategy for elucidating the genetic basis of important plant traits, in particular those associated with transgressive variation (the occurrence of progeny displaying phenotypes more extreme than either parent). We are using molecular markers to assess the genetic diversity of cultivated rice (Oryza sativa) and its ancestor (O. rufipogon) and will test the hypothesis that the natural population structure of cultivated rice and its progenitor are indicative of general combining ability, similar to the heterotic groups of maize.

We will explore the degree to which the sub-population structure of rice can be used to predict transgressive variation in both hybrid and inbred progeny and will work to characterize the underlying genetic basis of this phenomenon.
To do this, we will:

  1. Assemble a diverse panel of germplasm that reflects the diversity of wild and cultivated rice and make it available through the Genetic Stocks-Oryza (GSOR) at the Dale Bumpers National Rice Research Center (DBNRRC) in Stuttgart, Arkansas.
  2. Develop a 10,000 SNP chip for rice and use it to genotype the diverse panel of germplasm.
  3. Evaluate core morphological and developmental phenotypes in replicated field trials and laboratory assays to provide the basis for association mapping.
  4. Develop six interspecific libraries of chromosome segment substitution lines (CSSLs) from inter- and intra-subpopulation crosses between O. sativa and O. rufipogon to identify genomic regions associated with transgressive variation.
  5. Develop near isogenic lines (NILs) containing introgressions from O. rufipogon in elite O. sativa backgrounds as sources of germplasm for variety improvement in rice.

This project is funded by the National Science Foundation under NSF Grant 0606461: Exploring the genetic basis of transgressive variation in rice.