MOLECULAR MARKERS ENABLE THE IDENTIFICATION OF CONTAMINANTS IN PRODUCTION FIELDS OF ‘CAPTIVA’ ST.AUGUSTINEGRASS

摘要

To ensure the purity of a clonally propagated cultivar,strict guidelines are followed during its registration and release.Cultivar contamination can result from mechanical transfer of other cultivars/genotypes,seedlings,and random somatic mutation.Once contamination has occurred,it can be very difficult and time-consuming to coordinate an effective strategy to identify and contain the problem.‘Captiva’ is a recently released St.Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] cultivar from the University of Florida.In mid-2009,reports began to surface in Florida of off-type plants with different leaf color,texture and growth habit from Captiva.In this study,eight AFLP primer combinations were used to identify genetic variants or contaminants in Captiva foundation,registered,and certified fields.Six other St.Augustinegrass cultivars were also included as checks.Genetic similarities between cultivars and putative contaminants were used to verify sample identity as well as associate off-types with cultivar checks.Forty-nine percent of the contaminants were identified as ‘Palmetto’,eight percent as ‘Raleigh’,seven percent as ‘Sapphire’,three percent as ‘Floratam’,one percent as ‘Floraverde’,and three percent of contaminants were not identified.UPGMA analysis and principal coordinate analysis confirmed these results.An AMOVA ran with only true Captiva samples indicated no significant variation among samples from different field types.This study provides further evidence that molecular markers can be successfully used to quickly identify contaminants and aid sod producers in efficiently quarantining problematic cultivar sources.