Variability of clones in acorn production and its effect on effective population sizes and genetic diversity of crops in clonal seed orchards of pedunculate oak (Quercus robur L.) in Croatia

Sa？etak In this study we wanted to investigate different parameters providing informations about the efficassy of orchards in producing genetically diverse progeny. We used available inventory data from the company ？Croatian Forest” ltd. about the numbers and the age of ramets, as well as evidented crops in two clonal seed orchards (CSOs) of pedunculate oak : CSO ？Ple？？ice” and CSO ？Petkovac”. For CSO ？Ple？？ice” we used inventory data on ramets and crops for the years 2003, 2006, 2007, 2008, 2009 and 2010. and for CSO ？Petkovac” for the years 2003, 2004, 2005, 2006, 2008, 2009 and 2010. After 2010 the collection of crops per clone was abandoned in both orchards and we only have data for overall crops in the orchards, until the year 2017. We calculated the amounts and variability of acorn crops in different years, as well as projections of crops for years 2018 and 2019 based on polynomial regression curves, for all years of evidented crops between years 2003 and 2017. Results are shown in Table 1 and Figures 1 and 2. All other analysis were possible only for years in which crops were collected separately by clones. We used Pearson’s product-moment and Spearman’s rank correlations to compare distributions of crops per clones between pairs of investigated years, ie. rank of clones in crops production between investigated years. Both correlations were mostly statistically significant with some exceptions (Table 2) Clone fructification balance described by cummulative curves of acorn production in different years, per percentage of fructifying clones is shown in Figures 3 and 4. Clone balance curves in both orchards show irregular distribution of crops per clones, meaning that in investigated years minority of clones contributed to majority of crops. In conditions of equal clone fertility and maximal sinchronicity of clones, clone’s contribution to crops would be in concordance with the number of its ramets (clone size). Table 3 shows that in CSO Ple？？ice this correlation was weaker then in CSO Petkovac and, unlike in CSO Petkovac, not significant in all years. Estimations of effective population sizes and genetic diversity of crops in different years is shown for female clone fertility in Table 4. For calculations of biparental contribution of clones, we used three scenarios encompassing various versions of potential male contribution in effective population sizes. Results are shown in Table 5. The values of effective (status) number of parents (Np) for the first scenario, where male contribution is proportionate to the percentage of clone’s ramets in the