RESTRICTION-FRAGMENT-LENGTH-POLYMORPHISM ANALYSIS OF PLANT GENOMES AND ITS APPLICATION TO PLANT-BREEDING

This chapter reviews the restriction fragment length polymorphism (RFLP) linkage maps and genome localization of genes of interest. The potential of RFLPs as diagnostic markers became evident from the studies of the human globin genes where a direct correlation between the sickle-cell mutation carried by a specific β-globin allele and the presence of certain RFLP fragments were evident. RFLPs are the first class of genetic markers that allow the construction of highly saturated linkage maps. A prerequisite for marker-based selection is the identification of RFLP markers tightly linked to a trait of agronomic interest. The most general approach to achieve this is the initial construction of a complete RFLP linkage map. Markers evenly spaced on chromosomes are then used to scan the genome in individuals of progenies segregating for the traits of interest and for the RFLP markers. For the construction of RFLP linkage maps, parents are chosen that show the maximum of polymorphic loci to ensure the mapping of as many marker genes as possible per unit of resources available. In self-fertilizing species, the populations analyzed with RFLP markers are the same as those used for the segregation analysis of morphological markers. In terms of scientific progress, the old disciplines of quantitative genetics and plant taxonomy have been revived by the RFLP approach and the young discipline of plant tissue culture has become a valuable analytical tool. © 1992 Academic Press Inc.