CORN POPULATIONS WITH A BROAD GENETIC BASE

Abstract

A population with a broad genetic base (PBGB) is that one formed from the recombination of a large group of con­trasting genotypes, and which has received very little or no selection at all. The main purposes of a PBGB in a maize breeding program are: a) to reduce the number of genotypes to work with, and b) to promete a greater recombination among the components, which in turn may facilitate the ob­tainment of better genotypes at medium and long term. Ho­wever, this procedure requires several recombination cycles, and besides sorne desirable traits may become too "diluted" the frequency of sorne desirable traits may decrease consi­derably, causing difficulties for their recovery.  Because of the large phenotypic variation, et is suggested to per­forma farnily selection in these populations rather than mass selection.
Sorne experiences in the formation of PBGB in México are presented, including an indication of the genotypes eva­luated as well as those to be incorporated in the future. It is also proposed a group of the PBGB is considered to be convenient required for the different environments condi­tions and farming systems for maize in México.