Abstract: Among the hierarchies of biodiversity,genetic diversity is variable and difficult to measure.How-ever,it is the basis of all the other diversities and is also the essential element to avoid species ex-tinction and gene losse, and to protect subspecies,races and clones.Some recently developed molecular biology techniques,especially RFLP,PCR and RAPD metheds,may be used in the ex-amination of hybridization and introgression from other species,the geographical structure of population of a given species or to investigate the differentiation of closely related species.In gen-eral,they are powerful tools in determining the potential extinction, declination and genetic di-versity conservation of forest species.

Key words: wheat, TaCRT-A gene, single nucleotide polymorphism, haplotype, drought resistance, genetic mapping.