Marc, you might find the attached paper interesting, especially the introduction which summarizes past findings at the time (1992).
"
Powers and Lyon (1941) divided earliness into three stages: 1) days from
sowing to anthesis, 2) days from anthesis to first fruit set, and
3) days from first fruit set to first ripe fruit. They concluded
that there was sufficient variation within these stages to consider
each a unique and heritable trait." This has been borne out by present day molecular studies, notably Lindhout et al (1994), identified 3 distinct loci corresponding to the three defined stages.
http://link.springer.com/article/10.1007%2FBF00022528
The intro attached below also talks about the dominance of earliness, and says "
The F1 hybrid mean for earliness closely resembles that of the early parent and is often significantly earlier than the late parent (Corbeil, 1964; Daubeny, 1961; Honma
et al., 1963; Lyon, 1941; Powers and Lyon, 1941; Tayel et al.,1959). " That would be most noticeable where there's a big difference in earliness of the parents.
There's been lots of research on the "sowing to anthesis" stage, but most everything I've found has rolled the second two stages into one instead of looking at them separately. Maybe there are reciprocal dominance effects in one of those stages that hasn't been noticed because of the overall dominance of earliness traits.
