Diversity in Wild Apple Species of Chinese Origin

The Malus collection in the USDA-ARS National Plant Germplasm System has twelve wild species of apple collected from China at the Plant Genetic Resources Unit (PGRU) in Geneva, NY.  Between 8 and 148 individual trees represent each species. The assignment of seedling trees to specific species has been difficult due to the high levels of variation observed within species. We have collected phenotypic, ploidy, genotypic, and chloroplast sequence data for each of the field trees maintained at the PGRU that originated from seeds collected during plant explorations in China.  Characteristic fruit and leaf characteristics specific to each species have been identified.  Ploidy data have revealed that some species are diploid while other species have individuals with ploidy levels that range from diploid to hexaploid.  Chloroplast sequence data have aided in species classification and phylogenetic analyses.