Plant & Animal Genomes XVII Conference

January 10-14, 2009
Town & Country Convention Center
San Diego, CA

Exploiting Natural Variation In Rice: Construction Of Chromosome Segment Substitution Lines (CSSLs) And Interspecific Bridges (iBridges)

Alain M Ghesquiere , Mathias Lorieux

  LGDP IRD/CNRS/Perpignan University 911, Av Agropolis BP 64501 34394 Montpellier Cedex 5 France

While many interesting traits have been identified in African cultivated rice (O. glaberrima Steud.) and other rice relatives, introgression of those traits into cultivated rice (Oryza sativa L.) is very tedious and time consuming and breeders generally prefer the simplest path of intra-specific crosses since the sterility barrier is not an issue. In the case of O. glaberrima, we designed a crossing scheme that aims to produce interspecific bridges (iBridges) between the two cultivated species of rice. These iBridges comprise O. sativa lines carrying large introgressions of the O. glaberrima genome and that are producing fertile hybrids with O. sativa. These lines would be a material of choice for large-scale introduction of allelic diversity of African rice into Asian cultivated rice germplasm. In order to explore allelic variability at important genes (yield, drought tolerance, disease resistance), we are building a series of Chromosome Segment Substitution Lines (CSSLs) that bear small introgressions from O. glaberrima, O. barthii, O. glumaepatula, O. rufipogon and O. meridionalis. CSSLs represent a powerful material to study the genetic bases of segregating traits in case of interspecific crosses, which often show high hybrid sterility. We show here examples of transgressive behavior of CSSLs and virus resistance mapping.