Comparison of DNA marker technologies in characterizing plant genome diversity: Variability in Chinese sorghums

Chinese sorghums [Sorghum bicolor (L.) Moench] are reputed to have a narrow genetic base, resulting from infrequent introduction of exotic germplasm into China. We have used several different molecular approaches to evaluate diversity and relatedness in a selection of 34 Chinese sorghums. The results indicated that different DNA marker technologies for germplasm assessment yield comparable results, but that a relatively new technique termed inter-simple sequence repeat amplification (ISSR) was relatively rapid, reproducible, and inexpensive. Extensive diversity was observed within the Chinese sorghums, and an lines could be easily differentiated. Different lines collected from the same locality were found to exhibit particularly high levels of relatedness. Contrary to expectations, improved varieties were found to contain more diversity and to be more different from each other than were the Chinese landraces studied, suggesting recent introduction of non-Chinese germplasm into these improved materials.