In the meantime, knowledge about levels and patterns

of genetic diversity is often extrapolated to less known species on the basis of similar life history traits (Hamrick and Godt, 1990 and Hamrick and Godt, 1996), but care must be taken because correlations can be low and experience has shown that patterns of variation for every tree species are different (Rehfeldt, 1994). Among the many potential life history traits that might be expected to correlate with patterns of genetic diversity, Duminil et al. (2007) reported that genetic structure is generally related to mating system (selfing vs. outcrossing) for nuclear markers and seed dispersal mode (gravity vs. other categories) for maternally-inherited markers. It is pivotal that germplasm collection missions

capture a representative Natural Product Library in vivo sample of the genetic diversity of the target species that will be used in restoration projects. A number of general guidelines for tree seed collection aim to ensure a minimum level of genetic diversity, such as those published by The Australian Network for Plant Conservation Inc. (Vallee et al., 2004), the University of California (Rogers and Montalvo, 2004), the World Agroforestry Centre4 (ICRAF) (Kindt et al., 2006), ENSCONET, 2012 and Royal Botanic Gardens, Kew, 2003. Today, such guidelines appear to be largely unknown or overlooked by restoration practitioners or those who supply germplasm for restoration (Bozzano et al., 2014 and Godefroid et al., 2011). This is probably partly because Methocarbamol their implementation can be time and resource

demanding when applied to trees and partly because the negative effects of genetic homogeneity are often not immediately evident but accumulate NLG919 clinical trial over time (Rogers and Montalvo, 2004). Generally accepted rules have been developed for how many samples one should collect to capture at least 95% of genetic variation (measured as alleles) with the least amount of effort. Such rules relate to many factors, such as breeding or pollination system and flowering and seed characteristics (Dvorak et al., 1999 and Brown and Hardner, 2000). In general, a smaller number of seeds from many trees is a better sample of the genetic diversity within a population than many seeds from a few trees (Brown and Hardner, 2000). In a completely outcrossing species at least 30 randomly selected trees should be sampled (Rogers and Montalvo, 2004). If there is evidence of substantial self-pollination, a minimum sample of 60 trees is recommended (Brown and Hardner, 2000). Sampling from fewer trees will not capture the range of genetic diversity, whereas collecting more than the minimum sample size is recommended when the main aim is to maintain genetic diversity over generations (Rogers and Montalvo, 2004). Care should be taken to avoid unintentional selection of traits during seed harvest such as systematically discarding small seed, as this may lead to loss in the germplasm’s adaptive capacity to biotic and abiotic stressors such as pests or climate change.