Selection procedures used in plant breeding have gradually developed
over a very long time span, in fact since settled agriculture was ?rst
undertaken. Nowadays these procedures range from very simple mass
selection methods, sometimes applied in an ine?ective way, to indirect
trait selection based on molecular markers. The procedures di?er in
costs as well as in genetic - ciency.Incontrasttothegenetice?ciency,
costsdependonthelocalconditions encountered by the breeder. The genetic
progress per unit of money invested varies consequently from site to
site. This book considers consequently only the genetic e?ciency, i.e.
the rate of progress to be expected when applying a certain selection
procedure. Ifabreederhasacertainbreedinggoalinmind,
aselectionprocedureshould be chosen. A wise choice requires a
wellfounded opinion about the response to be expected from any procedure
that might be applied. Such an opinion should preferably be based on the
most appropriate model when considering the crop and the trait (or
traits) to be improved. Sometimes little knowledge is available about
the genetic control of expression of the trait(s). This applies
particularly in the case of quantitative variation in the traits. It is,
therefore, important to be familiar with methods for the elucidation of
the inheritance of the traits of interest. This means, in fact, that the
breeder should be able to develop population genetic and quantitative
genetic models that describe the observed mode of inheritance as
satisfactorily as possibl
