1a.Objectives (from AD-416):
The objective of this research is to evaluate, characterize, and utilize accessions from the world collection with an overall goal of releasing new germplasm resulting in a marked increase in hybrid grain yields. The specific objectives include the development and utilization of genotyping methodology developed by the ARS incumbent for marker-assisted selection of photoperiodism; the genetic fingerprinting of tropical accessions and photoperiod-converted materials to obtain a catalog of the regions of the tropical genomes that are critical for agronomic performance; map and identify markers linked to additional trait loci including dwarfism genes for use in marker-assisted selection; and investigate value-added traits that emerge during the conversion of tropical sorghums to temperate adaptation.
1b.Approach (from AD-416):
Utilize molecular markers linked to photoperiod (ma) genes to selected backcross progeny during the introgression of photoperiod-insensitive alleles into tropical germplasm. Utilize Diversity Array Technology (DarT) markers arrays to fingerprint tropical accessions while fingerprinting backcross-derived lines to catalog genomic blocks that are inherited from the tropical accession or the temperate donor parent. Utilize mapping populations developed by the ARS incumbent or MMR Genetics to map additional trait loci including dwarfism genes, and utilize molecular markers linked to these traits to expedite their introgression during the conversion of tropical accessions to photoperiod-insensitive, dwarf-germplasm suitable for growers in temperate climates.
The goal of this project is to convert tall and late-flowering ARS sorghum accessions to short and early flowering types by transferring photoperiod-insensitive and dwarfing genes into the accessions. Accessions that would otherwise flower too late or that would be too tall to be productively used in sorghum improvement in temperate environments like those of the U.S. will be made available. In FY 2013, project-developed short-stature, early flowering germplasm was released to breeders in the U.S. and abroad. Project work, as it continues, will develop foundational information that will be used by the cooperator and others in the sorghum breeding community to develop new photoperiod-insensitive sorghums for productive use by farmers in temperate agricultural zones worldwide.