The Proportion of Hybrids in Seed From a Seed Orchard Composed of Two Larch Species (L.europaea and L.leptolepis)

1991

S. 631-640

4 Abb., 3 Tab., 13 Lit. Ang.

Unselbständiges Werk

200041332

The proportion of hybrids in the seed produced in an orchard containing one European larch (Larix europaea) clone used as maternal tree and 271 Japanese larch (Larix leptolepis) clones used as pollinators was determined by isoenzymatic methods. On the basis of the 2 enzyme systems, Shikimate dehydrogenase (SKDH) and NADH dehydrogenase (NDH), the 2 larch species could be unequivocally distinguished in this case and therefore the proportion of hybrids and selfings (individual and clonal) exactly determined. The genetic control of these enzyme systems was analyzed by means of offspring of controlled (including reciprocal) crossings between one European and one Japanese larch. Five samples of different crop years of the hybrid seeds were examined. The proportion of full seeds ranged from 22-60% and the proportion of hybrids in full seed from 68.6-84.6%, thus showing that this method of producing hybrids is very efficient. A further advantage of the use of 2 enzyme systems is the easier detection of minimum amounts of contamination, which in this case ranged from 1.0-6.7%. The possible influence of the parental genotypes on the genetic structure of hybrids and possible explanations for the origin of the contamination are discussed.