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.
This is a new project, with the goal of transferring photoperiod-insensitive sorghum genes into ARS-maintained sorghum germplasm accessions whose current late-flowering response results in delayed grain development and poor maturation in temperate climates. Work in FY 2010 focused on project planning and protocol development, but also included successful isolation of DNA from germplasm supplied by the cooperator that will be genetically characterized utilizing molecular markers. Project work, as it progresses, will develop new information that will be foundational to the efforts of plant breeders to develop new photoperiod-insensitive commercial sorghums for productive and profitable utilization in temperate agricultural zones worldwide.