Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/1998
Publication Date: N/A
Technical Abstract: DNA markers can assess close genetic relationships between individuals of a crop as when one variety is developed (i.e., "essentially-derived") from another. An acceptable threshold, based on empirical results, should be established for a crop to indicate what constitutes an "essentially-derived" variety in the absence of pedigree information. Empirical data could settle infringements of intellectual property, but data are not being generated for most crops. Thus, our objectives were to characterize genetic relationships among broccoli varieties "essentially-derived" from known parents using random amplified polymorphic DNA (RAPD) markers as a measure of genotype and provide an empirical basis for threshold levels in this crop. Six hybrids and three inbred lines developed from each of the hybrids (24 entries) were evaluated by RAPD analysis. RAPD assays were conducted using 23 different oligonucleotide 10-mers. Of 179 RAPD bands scored, 94 were polymorphic among entries. Similarity indices were computed from RAPD data, and a multi-dimensional scaling (MDS) plot was constructed. Similarity indices for all comparisons ranged from 0.40 to 0.90. 'High Sierra' and its derived lines were the most closely related group with indices from 0.81 to 0.90. With 'High Sierra', 'Sultan', and 'Marathon', the three derived lines were more closely related to their respective parental hybrids than were other entries. The hybrids 'Futura', 'Everest', and 'Viking' were more genetically similar to others than to their derived lines. Threshold levels based on data from 'High Sierra', 'Marathon', 'Sultan' and their derived lines would not identify "essentially-derived" lines developed from other hybrids.