ASSOCIATION BETWEEN DNA MARKERS AND LOCI CONTROLLING AVOCADO FRUIT TRAITS

Authors: SHARON, DROR - HEBREW UNIV. OF JERUSALEM; HELLEL, JOSSI - HEBREW UNIV. OF JERUSALEM; MHAMEED, SAMIR - HEBREW UNIV. OF JERUSALEM; CREGAN, PERRY; LAHAV, EMMANUEL - HEBREW UNIV. OF JERUSALEM; LAVI, URI - HEBREW UNIV. OF JERUSALEM

Submitted to: Journal of American Society of Horticulture Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/13/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Genetic linkage maps provide road maps of the chromosomes of a plant or animal species. Molecular genetic markers are the milestones or defined points along these road maps. The first objective of the application of genetic maps to plant improvement is to identify the position of important genes that control crop growth, disease resistance, or quality in reference to the genetic milestones on the linkage map. The ultimate goal is to associate a particular form of a genetic marker with a desired crop characteristic. Thus, the plant breeder can select for the desired trait indirectly by the use of the genetic marker rather than by direct measurement of the trait in question. In a tree species in which it takes many years to reach maturity, it would be useful to eliminate progeny with little value based upon the genetic markers they carry so as to allow the breeder to focus on trees with a maximum chance of yielding superior progeny. This work demonstrates the application of a newly developed genetic map of the avocado to find associations with fruit quality. Genes controlling seven of nine fruit traits appeared to be associated with one or more genetic markers. The genetic control of fibers in the flesh of the avocado fruit was associated with one group of markers and with one of these markers in particular. This information is of particular interest to those working in the improvement of avocado..

Technical Abstract: The detection of association between DNA markers and loci controlling traits of interest in an outbred population is complicated and requires highly polymorphic markers. A genetic linkage map of avocado, recently generated consists of simple sequence repeat (SSR) markers as well as DNA fingerprint (DFP) and random amplified polymorphic DNA (RAPD) markers. These markers were used to detect association with loci controlling nine avocado fruit traits. Two statistical methods were used: one-way analysis of variance and interval mapping. Seven traits were found to be associated with at least one of the 90 DNA markers. Based on the two statistical approaches, a locus controlling the presence of fiber in the flesh was found to be located on linkage group 3. This locus was found to be located close to the SSR marker AVA04 having a highly significant value (P = 4.4 x 10E8) The haplotype analysis of linkage group 3 showed a putative interaction between the alleles of this locus.