Application of Molecular Markers for Avocado Improvement

Molecular markers serve as reference points that help locate agriculturally important traits on a genetic map. The denser the clustering of the markers, the greater is the precision with which an agronomic trait can be pinpointed. A trait and a tightly linked molecular marker are likely to be inherited together, such that selection for the marker can replace selection for the agronomic trait. Unlike many yield-related traits that only become apparent after 3-6 years in mature avocado trees, molecular markers can be identified at the seedling stage, eliminating the necessity of maintaining large numbers of seedlings of which only very few may prove to have superior genotypes. Once a particular marker has been shown to be tightly linked to a trait of interest a pool of candidate seedlings can be prescreened, retaining only those seedlings that possess the marker (and hence the trait). This highly efficient process is called marker-assisted selection (MAS) and makes avocado breeding both faster and more efficient.