Submitted to: Genes, Genomes, and Genomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/12/2012
Publication Date: 1/1/2013
Citation: Kong, W., Jin, H., Franks, C., Kim, C., Auckland, S., Goff, V., Rainville, L., Burow, G.B., Woodfin, C.A., Burke, J.J., Paterson, A. 2013. Genetic Analysis of Recombinant Inbred Lines For Sorghum Bicolor x Perennial S. Propinquum.. Genes, Genomes, and Genomics. 3:101-108. Interpretive Summary: Sorghum bicolor x S. propinquum is thought to be the widest genetic cross that can be made by conventional means, and these species offer opportunities to genetically dissect a wide range of traits related to plant domestication and crop productivity. We have produced and describe here a recombinant inbred line (RIL) population of 161 F5 genotypes that segregates for rhizomatousness. This S. bicolor x S. propinquum RIL population offers advantages over early-generation populations and will shed new light on the genetic, environmental, and physiological/biochemical factors that regulate plant growth and development.
Technical Abstract: From an annual S. bicolor x perennial S. propinquum F2 population used in early-generation genetic analysis, we have produced and describe here a recombinant inbred line (RIL) population of 161 F5 genotypes that segregates for rhizomatousness and many other traits. The genetic map of the recombinant inbred lines (RILs) derived from annual S. bicolor and perennial S. propinquum contains 141 loci on 10 linkage groups collectively spanning 773.1 cM. While most of the genome is well sampled on a genetic scale, on a physical scale markers are concentrated in distal regions and sparse in central regions of the chromosomes, in accordance with our prior observations that sorghum pericentromeric heterochromatin is recalcitrant to recombination, with the vast majority of recombination occurring in the distal euchromatin. The advancement of the RIL population in an environment to which the S. bicolor parent was well adapted (indeed bred for), but the S. propinquum parent was not, largely eliminated a locus for short-day flowering that confounded many other traits, but may have also caused some enrichment for S. bicolor alleles at other locations in the genome. Additional recombination that has accrued in the development of this RIL population may have also improved resolution of apices of heterozygote excess, accounting for their greater abundance in F5 than F2. The S. bicolor x S. propinquum RIL population offers advantages over early-generation populations that will shed new light on the genetic, environmental, and physiological/biochemical factors that regulate plant growth and development.