ISHS Acta Horticulturae 546: International Symposium on Molecular Markers for Characterizing Genotypes and Identifying Cultivars in Horticulture
CHALLENGES IN DEVELOPING MOLECULAR MARKERS FOR ALMOND (Prunus amygdalus) AND GRAPE (Vitis species) |
| Authors: | F.J. Ryan, C.A. Ledbetter, D.W. Ramming, D.E. Palmquist, D.E. Bell, S.J. Peterson |
| Keywords: | AFLP, linkage maps, phenetic characters, RAPD |
| Abstract:
Molecular markers based on DNA have utility in breeding programs for perennial crops. These markers can be used to measure variability, to provide markers for horticultural characteristics, and for linkage mapping. However, problems can be encountered in the application of this methodology. The results of two separate investigations will be presented to illustrate some of these challenges. We used RAPD analysis to investigate genetic variability among 26 heritage almond (Prunus amygdalus) accessions. Thirty polymorphic bands were utilized and phenetic analysis was conducted by UPGMA clustering after construction of a similarity matrix using simple matching coefficients. Clustering reflected the known pedigrees of the various accessions; however, comparison of these similarities with those estimated from other phenetic data, such as kernel or nut weights, revealed large differences in the clustering, probably due to the polygenic nature of the characters of interest and the limited amount of the genome surveyed in the RAPD analysis. A second investigation involved the development of molecular markers for characters in a cross of a parent of Vitis vinifera and a parent with V. labrusca heritage in a pseudo-testcross. Fluorescent-labeled amplified fragment length polymorphism (AFLP) markers were used to characterize the parents and a F1 progeny line. Segregation of many of the AFLP markers was observed in the progeny but a number of horticultural characters, such as muscat or labrusca flavors, were difficult to assign since their expression was influenced by ripeness and weather. Determination of molecular markers closely linked to these characters may require quantitative measures of associated flavor components. | |
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