Mating system in a low-density natural population of the dioecious wind-pollinated Patagonian Cypress

PASTORINO, MARIO JUAN; GALLO, LEONARDO ARIEL

GENETICA

Springer

Año: 2006 vol. 126 p. 315 - 321

0016-6707

The mating system of a species is an essential factor that determines the genotypic frequencies of its populations in each generation. Thus, knowledge in this regard is important in the application of practical measures in conservation and forest tree breeding. Austrocedrus chilensis (D.Don) Pic. Ser. et Bizzarri is a member of the Cupressaceae native to the Andean-Patagonian Forest of Argentina and Chile with regional economic importance. It is a dioecious tree with pollen and seeds distributed by wind. Isozyme markers were utilized to study the mating system of this species through the survey of individual effective pollen clouds in a natural low-density population. If random mating occurs, effective pollen clouds that pollinate single seed trees are expected to be genetically homogeneous. The classical Hardy–Weinberg test of panmixia was also performed. Although it failed to reject random mating, the analysis of the pollen clouds showed that this mating pattern does not occur. Evidence of locally distributed heterogeneous pollen clouds is presented. The two methods are critically compared.