mating system and population structure in a black spruce (picea mariana (mill.) b.s.p.) clonal seed orchard in northwestern ontario
abstract
multi-locus enzyme systems were studied in a black
spruce {picea maniana (mill.) b.s.p.) clonal seed orchard in
northwestern ontario. the embryonic and megagametophytic
tissues of each clone were sampled and electrophoretically
analysed to examine the inheritance pattern of 8 polymorphic
loci. with the exception of leucine aminopeptidase (lap) and
aconitase (aco), allozyme segregation followed expected 1:1
ratios. the mating system is characterized by a moderate
level of selfing (s=0.15) and a small effective population
size. the ratio of genetically effective males to receptive
females was calculated to be 0.31. although the parental
population was in hardy-weinberg equilibrium, the majority of the enzyme systems examined revealed a deviation from the
hardy-weinberg equilibrium in the filial generation. several
loci exhibited heterogeneous pollen pools and there was an
observed excess of heterozygotes. indications of non-random
mating and small effective population size invalidate two
basic seed orchard assumptions, namely, random mating and
large population size.
collections
- retrospective theses [1604]