There are a few techniques that have been developed and put into practise in order to reduce the observed maturation asynchrony. For example swathing acts to speed up the ripening of later florets by inducing desiccation. This involves the cutting of the crop prior to harvest, sometimes coupled with the spraying of desiccants (Flengmark, 1983; Bowerman, 1984) such as plyphosphate or diquat, which act to kill the plant and facilitate its rapid loss of moisture. Subsequently the immature pods rapidly ripen to improve the uniformity of crop maturation. Another approach is simply the direct combining of the crop, but should only be carried out when most of the seeds in the pod are dry and black (ie. mature). This leads to increased seed loss from dehiscence due to the length of time the crop is left to mature in the field (Macleod, 1981).
There have been chemical methods as well as those physical means described, such as the 'anti-shatter', or pod sealant, 'Spodnam' (di-1-p-menthene). It is designed to form an elastic, anti-transpirant coating on the pods so as to prevent, or reduce pod shatter during ripening. However, there are conflicting reports as to whether 'Spodnam' actually increases resistance to shatter (Szot & Tys, 1991; Bowerman, 1984).
Ogilvy et al (1992) reported on the effects of the various pre-harvest treatments on yield and
quality of winter oilseed rape. They concluded that in favourable conditions all of the above treatments
had little effect on yield, although swathing gave significantly higher
yields in windy conditions and desiccants were recommended in wet and late harvesting seasons
to ensure fast drying of crops.
<>