Establishment of a core collection for maize germplasm preserved in Chinese National Genebank using geographic distribution and characterization data

Since the 1980s, a large collection of maize has been preserved in the China National Genebank. To facilitate the evaluation and utilization of these valuable germplasm resources, a core collection was established. The collection was firstly divided into two groups, i.e. the landraces and inbred lines. The percentage of the original collection to be included in the core was given as 7% based on a previous study of sampling strategies in maize. Each group was sequentially stratified based on administrative provinces or regions and kernel types, and a clustering method was applied in further stratification. A logarithmic strategy was used to determine the number of entries in the core at each step. The process resulted in the maize core comprising 951 landraces and 242 inbred lines. Shannon-Weaver diversity index and means were used to validate the core. The core can be used effectively in further in-depth research and maize improvement. © 2004 Kluwer Academic Publishers.