PRODUCTION OF HYBRID SEED IN A SEED ORCHARD OF 2 LARCH SPECIES, LARIX-SIBIRICA AND LARIX-DECIDUA

The larch seed orchard studied is intended to produce interspecific hy brid seed between Larix sibirica and Larix decidua. Only the L. sibiri ca clone (half of the grafts) in the orchard was intended to act as th e seed parent, and the six L. decidua clones are pollinators. The prop ortion of hybrid seed produced was determined using Mdh3 locus as a ge netic marker. The mean percentage of hybrid seed produced by the graft s of L. decidua was 93, but that of the hybrid seed produced by L. sib irica was only 18. The results can be explained by differences in flow ering abundance. The grafts of L. sibirica produced several times more pollen than those of L. decidua. Contrary to the original plans, L. d ecidua should be used as the seed parent and L. sibirica only as the p ollen parent in the studied seed orchard.