13 CHAPTER 2 Soybean (Glycine max (L.) Merr.) Ram J. Singh, Randall L. Nelson, and Gyuhwa Chung CONTENTS 2.1 Introduction.............................................................................................................................14 2.2 Domestication and Dissemination of Soybean ......................................................................15 2.3 Botany .....................................................................................................................................17 2.3.1 Taxonomy ...................................................................................................................17 2.3.2 Morphology ................................................................................................................17 2.4 Gene Pools of Soybean ..........................................................................................................20 2.4.1 Soybean GP-1 .............................................................................................................20 2.4.2 Soybean GP-2 .............................................................................................................21 2.4.3 Soybean GP-3 .............................................................................................................21 2.5 Cytogenetics ...........................................................................................................................22 2.5.1 Evolution of the Glycine Genome .............................................................................22 2.5.2 Genomic Relationships among Diploid Species........................................................26 2.5.2.1 Genome Designation ...................................................................................27 2.5.2.2 Classical Taxonomy ....................................................................................27 2.5.2.3 Crossing Affinity .........................................................................................27 2.5.2.4 Chromosome Pairing...................................................................................27 2.5.2.5 Molecular Methods .....................................................................................30 2.5.3 Polyploid Complexes of G. tabacina and G. tomentella ..........................................30 2.5.3.1 Glycine tabacina (2n = 80).........................................................................31 2.5.3.2 Glycine tomentella (2n = 78, 80) ...............................................................31 2.5.4 Chromosomal Aberrations: Structural Changes.........................................................32 2.5.5 Chromosomal Aberrations: Numerical Changes .......................................................32 2.5.5.1 Autopolyploidy............................................................................................32 2.5.5.2 Aneuploidy ..................................................................................................32 2.5.5.2.1 Primary Trisomics .....................................................................32 2.5.5.2.2 Monosomics ..............................................................................33 2.5.5.2.3 Tetrasomics ...............................................................................34 2.5.6 Linkage Mapping........................................................................................................34 2.5.6.1 Chromosome Map .......................................................................................34 2.5.6.2 Classical Genetic Linkage Map ..................................................................34 2.5.6.3 Molecular Linkage Map..............................................................................35 3639_C002.fm Page 13 Wednesday, July 19, 2006 1:09 PM