Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: June 1, 1997
Publication Date: N/A
Technical Abstract: Broccoli (Brassica oleracea L.) breeders use anther or microspore culture to produce dihaploid (diploid) lines. During culture, polyploidization occurs and diploid regenerants can result. However, polyploidization may not occur at all, or it may involve a tripling or quadrupling of the chromosome complement. Thus, regenerants must be screened to identify diploids, the regenerants most likely to set seed and serve as inbreds. DNA flow cytometry has proven a useful procedure for determining ploidy of regenerants. In this study, we evaluated the effect of leaf age and sampling procedures on ploidy determination via flow cytometry. Anther derived plants were analyzed at a transplant stage and at a mature plant stage. In addition, stability of flow cytometry preparations and the stability of ploidy readings of leaves stored at 4 C were examined over seven days. In only one case out of 123 comparative assays did leaf age affect ploidy determination. Flow cytometry preparations and also leaves stored at 4 C gave consistent ploidy determinations up to four days after preparations were made or tissue was refrigerated, respectively. These results indicate that broccoli breeders can make flow cytometry preparations onsite and send them offsite for flow cytometry analysis. Alternatively, leaves could be refrigerated, sent offsite, and then prepared and analyzed at another location.