THE GENETIC RELATIONS BETWEEN LENGTH OF TIME TO GERMINATION AND SEED DORMANCY IN LISIANTHUS (EUSTOMA-GRANDIFLORUM)

The inheritance of speed of germination and its genetic relations with seed dormancy was investigated in lisianthus (Eustoma grandiflorum). The study was based on data from parental, F1, BC1F1 and F2 generation s of a cross between a normally germinating genotype (P1) and a chill- requiring genotype (P2). The mean post-chilling germination speed of P 2 was considerably lower than that of P1. Germination speed was found to be under nuclear embryonic control. Analysis of generation means fo r prechilled seeds revealed an additive gene action with complete domi nance of the alleles conferring higher germination speed, since the me ans of the F1 and the BC1(P1) were indentical to that of P1. Such domi nance was not found for unchilled seeds, in which the mean germination speed of the F1 and the BC1(P1) was lower than that of P1. It was hyp othesized that slow germination speed was induced by pleiotropic effec ts of seed dormancy alleles. Seed prechilling seemed to eliminate thes e effects in progeny heterozygous for dormancy alleles, but not in pro geny homozygous for dormancy alleles.