Genetic improvement: Conventional and molecular-based strategies

This chapter focuses on selected information reported since the 1987 edition of the Soybean Monograph as it relates methods and strategies for the genetic improvement of soybean. The genetic improvements have been accomplished mainly through the use of conventional breeding methods; however molecular-based plant-breeding techniques are assuming an increasingly more important role in genetic improvement. Each cycle of genetic improvement begins with the breeder making choices as to the parents to be used to create segregating populations. Molecular marker technologies have facilitated the construction of genetic maps of many organisms including important crop species. Genetic marker analysis can measure the effect of an individual quantitative trait loci at the allelic level. Genetic markers are potentially useful in plant-breeding programs for parental selection, donor trait and recurrent parent selection in backcross breeding, trait selection in segregating populations, and identification of new positive alleles in exotic germplasm.