Agronomy and Horticulture, Department of


Date of this Version



A DISSERTATION Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the degree of Doctor of Philosophy, Major: Agronomy; Under the Supervision of Professor P. Stephen Baenziger
Lincoln, Nebraska: January, 2010
Copyright (c) 2010 Anyamanee Auvuchanon


Genetic diversity of wheat cultivars from Turkey and the Great Plains was studied under the hypothesis ‘Turkey’ wheat originated from Turkey and is the original hard red winter wheat landrace in the Great Plains. Wheat cultivars in Turkey and the Great Plains were selected for adaptation in two countries which were similar in climate. Twenty-two Turkish and twenty-three Great Plains wheat cultivars were selected for this study using SSR markers, agronomic, and end-use quality traits data. Wheat cultivars were clustered into five groups based on SSR markers and the clustering largely followed their countries of origin and pedigree. Modern Great Plains wheat cultivars diverged from Turkey wheat and historic Great Plains wheat cultivars. Although cultivars from one gene pool were predominant in each cluster, cultivars from another gene pool were also present indicating genetic similarity. Field experiments were conducted in six environments in Nebraska. The cultivars and cultivar by environment interactions for nine agronomic and four end-use quality traits were significant. Most Turkish wheat cultivars were injured by the Nebraska winter; hence showed lower grain yields. Great Plains wheat cultivars diverged from Turkish wheat cultivars due to breeding for adaptation based on agronomic traits. Turkish and U.S. wheat cultivars clustered together for end-use quality traits indicating similar selection criteria. Cluster analysis based on agronomic and end-use quality combination indicated that wheat cultivars from two countries had separated. The original Great Plains wheat cultivars (Turkey and Kharkof) were clustered separately from modern Great Plains wheat cultivars by both SSR and combination of agronomic and end-use quality data. Our results suggested that breeding programs in both countries improved wheat cultivars for specific environment as the genetic diversity based on agronomic traits; nevertheless, SSR markers indicated that 130 years after the introduction of Turkey wheat, much of the genetic background of two wheat groups has been maintained. The better adapted Turkish wheat cultivars in Nebraska were Karasu-90, Alpaslan, Lancer, Dogu-88, Harmankaya, and Yildirim which can be used as parents.