Kang, K.S., Kjær E.D. & Lindgren D. 2001. Balancing gene diversity (status number) and nut production in Corylus avellana L. collections from native Danish populations. Scan. J. For. Res.

Theory on the balancing between gene diversity and amount of nut collection was developed and applied to Danish hazelnut (Corylus avellana L.) populations. By controlling female fertility based on power function [F(x)= x^a], a tradeoff between equalizing maternal contribution and obtaining an acceptable amount of nut was achieved, and gene diversity during the initial phase of mobilizing the natural gene pool could be managed. Constrains on nut production could be made on maternal proportion as both lower and upper bounds. For a case of the collection of hazelnuts from 264 individuals, the status number (N_s) was estimated to 149 based on female contribution if all nuts were collected and used. Higher status numbers could be obtained by balancing the number of nuts collected per tree, but such increase of the status number would result in substantial loss of nut production. If it was decided to truncate the progeny size at 50 nuts, which required restriction of the nut contributed equally from the 14% most fertile individuals to a maximum contribution of 0.74%. This increased the N_s from 149 to 201 while 85% of all nuts were included.