2012 Annual Report
1a.Objectives (from AD-416):
Objective 1: Identify and utilize fertility/sterility mutants in a phenotypic recurrent selection program for insect-mediated cross-pollination to increase hybrid seed production. Objective 2: Identify phenotypes/genotypes that can be characterized and molecularly mapped that contribute to insect-pollinator attraction and reward.
1b.Approach (from AD-416):
Soybean accessions in the USDA germplasm collection will be crossed with known cytoplasmic restorer lines to identify cytoplasmic male sterile cytoplasms. Sterility mutants (nuclear) obtained via gene tagging from the w4-mutable system will be characterized genetically. Both the cytoplasmic and nuclear sterility mutants will be used in a phenotypic recurrent selection system, with insect-mediated cross-pollination, to increase hybrid seed production.
The plant factors that contribute to the increased attraction/reward of the insect pollinators will be identified, characterized, and molecularly mapped.
Cytoplasmic male sterility is a type of plant sterility that would greatly enhance hybrid breeding in soybean. In certain genetic backgrounds and environments, male sterility is not complete in soybean, therefore, additional crossing and testing are needed to identify stable sterility systems. In 2012, supposed maintainer and restorer soybean germplasm was grown in the field for seed increase to maintain the germplasm. Soybean accessions in the USDA germplasm collection were crossed with known cytoplasmic restorer lines to identify cytoplasmic male sterile germplasm. Approximately 200 cross-pollinations were made to initiate molecular mapping studies of all known male-sterile, female-fertile mutants. Evaluated approximately 2000 F2:3 progeny rows of 8 male-sterile, female-sterile mutants for molecular mapping to determine the genotype of F2 plants. These germplasms will be useful to plant breeders to develop hybrid soybean that are expected, after selection, to have superior agronomic performance.
Perez-Sackett, P.T., Palmer, R.G. 2012. Effect of day and night temperature on the expression of male sterility of nuclear male-sterile (ms8ms8) soybean. Euphytica. 186(3):847-853.
Findley, S.D., Pappas, A.L., Cui, Y., Birchler, J.A., Palmer, R.G., Stacey, G. 2011. Fluorescence in situ hybridization-based karyotyping of soybean translocation lines. Genes, Genomes, Genetics. 1:117-129.