It is well known that commercial lines of seed of Crested Dogstail often exhibit marked differences in colour, some samples in bulk being canary yellow while others are almost black. There is often great variation within a line in the colour of the individual seeds which may vary from greenish yellow through various shades of yellow, orange, and brown to almost a black colour. In some samples, however, the range in colour is more restricted, such samples naturally exhibiting a more uniform appearance.
It is important to understand at the outset the commercial attitude towards the colour of a sample. Until recently the great demand by farmers was for seed of a bright yellow colour, which, although of a lower bushel weight than darker seed, was nevertheless more attractive in appearance. As a general rule the germination was good so that as far as utilisation in New Zealand was concerned this type was satisfactory.
General observations have shown that there are distinct differences between plants in regard to the colour of the seeds at comparable stages in growth. It was considered that any data which could throw light on colour development and further facts on its probable utility would be useful.
The investigations recorded in Part 1. were carried out with the object of attempting to ascertain whether the darkness in colour of Crested Dogstail seed is due to maturity alone, or whether there are other factors concerned.