Determination of the minimum number of stool bed ortets required to capture a desirable genotype from full-sibling family crosses

Two important questions for clonal forestry are: (1) how many ortets must be established to ensure that one or more of the best genotypes in a family will be available for field tests and plantation establishment; and (2) how certain can one be that at least one top genotype will be present in a sample of n ortets. In this study, we calculated the level of confidence (LOC) in having included one or more desirable, rootable genotypes in a random sample of n ortets from a full-sibling family. We also calculated the number of unique ortets required to achieve a given LOC in having included one or more desirable, rootable genotypes in a sample. In general, when the sample size is small, either because the original number of ortets was low or because of poor rootability, the LOC is lower. When rootability is low or when only a small percentage of the possible genotypes is considered desirable, the original number of ortets required to achieve a given LOC is higher. Both LOC and sample size are highly influenced by the target number of desirable genotypes to be captured in a sample of ortets.