Development and Utilization of Genomic Resources for Sorghum Improvement.
Patricia E. Klein1, Robert R. Klein2, and John E. Mullet1. (1) Institute for Plant Genomics and Biotechnology, Texas A&M University, College Station, TX 77843-2123, (2) SPARC, USDA-ARS, 2881 F&B Rd., College Station, TX 77845
A suite of genomics tools in Sorghum bicolor have been developed over the past ten years including extensive genetic and physical maps, a detailed understanding of genome and chromosome architecture, gene expression profiling technology, and a deep EST collection. In addition, an 8X whole genome shotgun sequence of sorghum was recently released by the DOE/JGI (http://www.phytozome.net/sorghum). These genomic resources are now being utilized to investigate the underlying mechanisms regulating a number of important agronomic traits in sorghum including stress adaptation, fertility restoration, and maturity. The development of saturated sorghum genetic maps combined with high-throughput marker systems has allowed us to detail the genetic diversity amongst elite breeding materials across complete chromosomes, and thereby better understand crop improvement processes that have shaped the genomic diversity of elite sorghum cultivars. These graphical genotypes reveal genomic signatures of historical breeding decisions, especially evidence of directional selection during the conversion of tropical accessions to temperate adaptation. In addition, we have utilized our high density genome map to map-base clone a major fertility restoration gene in sorghum (Rf1) as well as a gene involved in aluminum tolerance (AltSb), and to accelerate progress towards map-base cloning several genes controlling the stay-green drought tolerance trait.