|Robbins, Matthew - OHIO STATE UNIV, OHIO|
Submitted to: Plant and Animal Genome VX Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: December 1, 2006
Publication Date: January 13, 2007
Citation: Robbins, M.D., Staub, J.E. 2007. Comparative analysis of marker-assisted and phenotypic selection in cucumber [abstract]. Plant and Animal Genome VX Conference Abstracts. p. 27. Technical Abstract: Previously developed marker-trait associations in cucumber (Cucumus sativus L.) were employed to compare the effectiveness of marker-assisted selection (MAS; genotyping with 20 molecular markers) to phenotypic selection (PHE; open-field evaluations) for multiple, quantitative traits. Four inbred lines were intermated then bulked maternally to create four distinct base populations at selection cycle 0 (C0). Each of these populations underwent MAS, PHE, and random mating (RAN; no selection control) for three cycles. The four traits under selection, multiple lateral branching (MLB), gynoecious sex expression (GYN), earliness (EAR), and fruit length to diameter ratio (L:D), are controlled by relatively few (2-6) QTL per trait and related to yield. The trait values at C0 and responses to selection varied among the four populations. In general, C0 populations with inferior trait values either responded favorably to selection or remained constant while those with superior trait values either did not change or decreased. Both MAS and PHE provided improvements in all traits under selection in at least one population with the exception of MAS for EAR. Improvements of MLB and L:D were similar after MAS and PHE, but PHE was more effective for GYN and EAR. Responses to PHE were superior in three of the four populations, although the population for which MAS was superior showed the only increase in yield (fruit/plant), which was not under direct selection. These results indicate that both MAS and PHE are useful for multi-trait improvement in cucumber, but their effectiveness depends upon the traits and populations under selection.