Assessment of molecular and phenotypic diversity among winter wheat cultivars

Comparing results of different genetic diversity estimates can be useful in parental selection for plant breeders. Forty winter wheat cultivars, from three Croatian breeding centres and four foreign countries, were used to utilize and compare agronomic, morphologic and molecular based genetic diversity estimates. Ten morphologic descriptors according to UPOV guidelines and eight agronomic traits were used to establish phenotypic data. Molecular data consisted of 26 SSR and four combinations of AFLP markers, covering all three wheat genomes. Agro-morphologic data showed variability especially regarding plant height (CV=18.44%), yield (CV=22.02%), and ear emergence (range=8). Discriminant analysis confirmed grouping among cultivars was mostly influenced by number of days to heading and yield. The four AFLP primer combinations and 26 SSR markers yielded 108 polymorphic bands. The UPGMA based on phenotypic data, arranged cultivars in four clusters, with one distinctive outlier, cultivar U1. The UPGMA based on molecular data also arranged cultivars in four clusters, with one distinctive outlier, cultivar Antonius. The similarities based on all four genetic diversity estimates reflected, on average, the degree of relatedness of cultivars used. No correlations between phenotypic and molecular data were found implying that both types of data should be used for genetic diversity estimates in order to cover wider variability between tested cultivars.