The genomics revolution of the past decade has greatly enhanced our understanding of the genetic composition of living organisms including many plant species of economic importance. Complete genomic sequences of Arabidopsis and several major crops, together with high-throughput technologies for analyses of transcripts, proteins and mutants, provide the basis for understanding the relationship between genes, proteins and phenotypes. Sequences and genes have been used to develop functional and biallelic markers, such as single nucleotide polymorphism (SNP), that are powerful tools for genetic mapping, germplasm evaluation and marker-assisted selection