ccChooser can be used to developing and evaluation of core collections for germplasm collections (entire collection). This package used to develop a core collection for biological resources like genbanks. A core collection is defined as a sample of accessions that represent, with the lowest possible level of redundancy, the genetic diversity (the richness of gene or genotype categories) of the entire collection. The establishing a core collection that represents genetic diversity of the entire collection with minimum loss of its original diversity and minimum redundancies is an important problem for gene-banks curators and crop breeders. ccChooser establish core collection base on phenotypic data (agronomic, morphological, phenological).