PHENOTYPIC SELECTION FOR WINTER SURVIVABILITY AND MOLECULAR CHARACTERIZATION IN TURF BERMUDAGRASS POPULATIONS

摘要

Common bermudagrass [Cynodon dactylon (L.) Pers.] is the most important warm-season turfgrass species in the world.As its use penetrates into the transition zone in the U.S.,winter kill becomes a critical concern.Genetic enhancement of cold hardiness has been an important goal in turf bermudagrass breeding.The objectives of this study were to (1) evaluate winter survivability and make selections in breeding populations; and (2) evaluate the allele frequencies of randomly selected genetic loci.Two populations respectively from ‘Riviera’ (RV) and ‘Yukon’ (YK),each encompassing 210 plants,were field established at the Landscape and Horticulture Center of the University of Illinois,Urbana-Champaign (40’05” N.Lat.,88’14” W.Long.) in the summer of 2009.Spring greenup was visually evaluated on April 22,2010.There were large variation for the trait among plants in the two nurseries.Forty-eight superior plants were selected from the RV nursery and 50 from YK nursery in July,2011.Forty-four simple sequence repeat (SSR) markers were selected to characterize allele frequencies in the selected RV survival population (RVs) versus original RV population (RVo),and the selected YK survival population (YKs) compared to original YK population (YKo).The SSR markers collectively amplified 421 scorable polymorphic bands in RVs and RVo populations,and 385 bands in YKs and YKo populations.χ 2 tests indicated significant allele frequency changes occurred in 38 loci in RVs vs.RVo populations,and 16 loci in YKs vs.YKo populations.Allele frequencies of 15 SSR markers changed significantly in both YK and YKo and RV and RVo populations,suggesting a few of the significant markers are likely linked to winter survivability in the populations.Selected germplasm could be valuable for the development of new cold hardy turf cultivars in bermudagrass.