LOSS OF GENETIC DIVERSITY FROM HETEROGENEOUS SELF POLLINATING GENEBANK ACCESSIONS

Genebank seed accessions of predominantly self-pollinating species may be stored either as bulked (mixed) seed lines or as pure line cultiva rs. If seed lines are bulked in storage then when considered over seve ral regeneration cycles, loss of genetic diversity within heterogeneou s self pollinating genebank accessions is shown to be severe. This wit hin-accession loss of diversity represents opportunities foregone thro ugh the random loss of individual genotypes. Amongst working collectio ns, the utility and repeatability of genebank accessions is paramount in the justification of the germ plasm resource. Therefore, the only p ractical solution to the management of predominantly self-pollinating species is to preserve individual accessions as pure lines.