Abstract

Zewdu Asrat*

QTL mapping is process of locating genes with effects on quantitative traits using molecular markers. It is basic research activity requiring careful planning of crosses and high precision phenotyping. It is used to offer direct mean to investigate the number of genes influencing the trait, to find out the location of the gene and to know the effect of dosage of these genes on variation of the trait. Genetic mapping is the first step to map based cloning. It is used for DNA based Marker Assisted Selection (MAS) and carrying out study on linkage between genes of interest. Genetic properties Of QTL, environmental factors, experimental errors in phenotyping and size of population are main factors affecting the QTL detection. The environment directly affects the expression of quantitative traits and when some experiments are conducted on the same sites for various seasons, it helps to detect the effects of environments on the QTL having influence on the traits of interest.