GENETICS OF GENETIC CONSERVATION .1. SAMPLE-SIZE WHEN COLLECTING GERMPLASM

A sample of about 172 plants, drawn at random from a population of a target species, is of sufficient size to conserve at a very high probability, all or very nearly all of the polymorphic genes that are segregating in the population, provided that their frequency is not less than 0.05, irrespective of whether the individuals of the species set all of their seed by self- or by cross-fertilisation or a mixture of both. When samples are taken from a number of populations, the size of the sample drawn from each need be no larger than 172 divided by the number of populations visited. It is pointed out that implementation of this conclusion could lead to very considerable saving of resources in both the collection and storage of material in gene banks.