Molecular breeding and the impacts of some important genes families on agronomic traits, a review

Gene identification and evolution and also their impacts on agronomical traits are important variations between related species which are often because of differences in the cumulative actions of multiple gene products. Understanding genetic variability for agronomic traits is important parameter of breeding programs for broadening the gene pool of different crops. The Short-Chain Dehydrogenase/Reductase (SDR) super-family is one of the largest known protein families and comprises thousands of members found in species ranging from bacteria to humans. SDR involvement has been demonstrated in a variety of primary and secondary metabolisms. Quantitative trait locus (QTL) mapping provides a starting point for dissecting complex traits into its component alleles which may help to quantify relative impacts of alleles on the traits and locates genomic regions responsible for marker-trait association, and provide a foundation of marker-assisted selection which expedites the breeding process given the proper estimation of position and the effects of QTLs. In this manuscript we have reviewed, molecular breeding and gene evolution and domestication in crops, and also survey some important reported genes which have notable impact on agronomical traits in various crops.