Genetic diversity in wild Spanish populations of Thinopyrum junceum and Thinopyrum junceiforme using endosperm proteins and PCR-based markers

The genetic variation of sixteen wild, Spanish populations of Thinopyrum junceum and Thinopyrumjunceiforme and their interspecific relationships were analyzed. The relationships between these species and the diploids T. bessarabicum and T. elongatum were also investigated. The number of phenotypes and the composition of bands yielded by the electrophoretic separation of endosperm proteins were used to estimate intra- and interpopulational variability. DNA polymorphism generated by 24 arbitrary 10-mer primers and 14 specific 20-mer primers was used to determine interpopulational variability and interspecific relationships. Jaccard's coefficient of similarity was used to analyze presence and absence data in the DNA polymorphism and endosperm protein determinations of individual plants. Pearson's product-moment correlation coefficient was used to analyse interpopulational variation using endosperm protein band frequency data. Dendrograms were constructed using an unweighted pair group method with arithmetical average (UPGMA). The high level of intrapopulational variability found in T. junceum and T. junceiforme was inconsistent with the traditional classification of these species as self-pollinating. The level of interpopulational variation varied according to the degree of polymorphism of the corresponding markers. The endosperm proteins and random amplified polymorphic DNAs (RAPDs) proved to be the most polymorphic markers to those used although only the former were able to distinguish between the different populations. Interspecific relationships were consistently confirmed by all the PCR-based markers, and were also in agreement with the results of other authors.