Location: Plant Introduction Research
Project Number: 5030-21000-065-01-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Aug 1, 2019
End Date: Jul 31, 2021
Utilizing available genomic and pedigree information, determine tropical genome segments introgressed in double haploid released (BGEM) maize lines, differentiate between temperate and tropical conserved regions, and compare nature of well or poorly adapted BGEM lines. Utilize trait performance and pedigree information from conventionally bred GEM releases in combination with these findings to guide selection of material worthy of development or for appropriate placement to address challenges to maize production.
The Germplasm Enhancement of Maize Project (GEM) has introgressed tropical germplasm into temperate maize germplasm over the past 25 years. More than 300 conventionally bred lines, and more than 200 doubled haploid lines have been released. Pedigree information and extensive information on traits such as flowering time, plant and ear height, agronomic performance, and resistance to various diseases are available. Challenges to use of unadapted, tropical germplasm in the GEM maize pre-breeding program include 1) photoperiod - addressing conversion of short day adapted germplasm to long day conditions during the introgression process to develop temperate environment-adapted material, 2) lack of heterotic pattern information that better informs decisions on breeding cross combinations, and 3) lack of information on intrinsic traits and/or alleles to guide selection of material worthy of development or for placement to support production in specific areas of adaptation or where superior traits are most needed, and 4) poor agronomics. Information is to be extracted from breeding nursery, agronomic performance testing, and disease resistance trials. Records have been maintained of materials that were or were not advanced based on performance or adaptation. Phenotypic and pedigree data can be provided by the PI to the Cooperator for analysis using the newly developed tools that identify both genetic and environmental determinants across diverse genotypes and environments. Daylength, temperature and thermal time records can be accessed. Planting date record is available. Genomic data (SNP or single nucleotide polymorphism) is available for most of the released conventional lines and doubled haploid, or BGEM-designated lines. Other public genomic data from institutions can be accessed and be considered in the context of releases that share common landrace or geographic origins with background of GEM germplasm. Available genomic information will be used to determine tropical genome segments which were introgressed, and to differentiate between temperate and tropical conserved regions. Insights will be gained by examining well and poorly adapted BGEM germplasm. Ultimately, these efforts will contribute to enabling the GEM project to better identify and target genomic regions necessary for adaptation and will aid in identification of exotic germplasm worthy of development. Analytical methods will be applied to understand performance and/or adaptation patterns, and to predict performance of breeding cross combinations. Cooperator and ARS PIs will work closely throughout process to develop useful procedures, review and consider interpretations of analyses. These findings will be used to inform future research approaches, and to aid in rapid adaptation of exotic germplasm to the temperate Midwestern U.S. If additional genomic characterization information resources become available, they can be integrated to potentially identify useful alleles associated with specific germplasm.