154
3.2 Effects of Storage Time of Primed Seeds on Sorghum
and Millet Plant Establishment and Yield
It may be difficult for the farmers to know what quantity of seeds to prime when the
rain starts, because that depends on how much land they will be able to sow in the
following day. If too many seeds have been primed, the question is what to do with
the seed surplus. A study was therefore initiated to assess the length of time it is possible to store the primed seeds without losing the effect of priming on seed germination, emergence, and crop growth. Sorghum seeds in this study were dried in shade
for 2, 24, 48, and 72 hours following seed priming, whereas millet seeds were dried
for 2, 24, and 48 hours. Neither sorghum nor millet showed any effect of drying time
on emerged plants, number of heads, and grain yield. This result demonstrates that it
is possible for farmers to store the seeds for up to 3 days if they are not able to utilize
all the seeds on the day of priming. This makes seed priming a more flexible approach
than if all the seeds need to be sown immediately following seed priming.
3.3 Environmental Conditions on the Response to Seed
Priming and Microdosing
It was important to determine the environmental conditions under which seed priming and microdosing would perform best. The relative yield between treatments
(T2, T3, and T4) and control (T1) was calculated; if it was above one, this would
indicate a positive effect of the treatment (priming and microdosing) as compared to
the control. This relative yield for each treatment and site was plotted against yield
of the control for the site. The yield of the control can be considered as an indicator
for the environment at the site as it is determined mainly by rainfall, soil conditions,
disease, pest, and weed pressure. The regression analysis showed that the relative
benefit of seed priming and microdosing was reduced when environmental conditions become more favorable (higher yields in the control).
In sorghum, there was hardly any effect of seed priming and microdosing when
the yield in the control was above 2000 kg/ha. Below a sorghum yield of 900 kg/ha
in the control, there was a good response to seed priming and microdosing. Between
900 and 2000 kg/ha, seed priming and microdosing had a positive effect, but the
effect was more variable. These results show that seed priming and microdosing are
technologies that are mostly suited to marginal environments (Figs. 1, 2, and 3).
The result for pearl millet showed that, as with sorghum, there is a decline in relative
yield between the treatment and the control when the yield of the control is increased.
As Figs. 4, 5, and 6 indicate, there is a consistent response to these treatments when the
yield in the control is below 500 kg/ha. Above 500 kg/ha in the control, the response in
comparison to the control is still evident, but the effect is more variable.
However, when plotting the yield in the control against the absolute yield
increase, no clear relationship was apparent (figure not shown). The same increase
in yield (kg/ha), as a result of the treatment, can therefore be expected across different yield levels in the control.
A. Coulibaly and J. B. Aune
3.2 Effects of Storage Time of Primed Seeds on Sorghum
and Millet Plant Establishment and Yield
It may be difficult for the farmers to know what quantity of seeds to prime when the
rain starts, because that depends on how much land they will be able to sow in the
following day. If too many seeds have been primed, the question is what to do with
the seed surplus. A study was therefore initiated to assess the length of time it is possible to store the primed seeds without losing the effect of priming on seed germination, emergence, and crop growth. Sorghum seeds in this study were dried in shade
for 2, 24, 48, and 72 hours following seed priming, whereas millet seeds were dried
for 2, 24, and 48 hours. Neither sorghum nor millet showed any effect of drying time
on emerged plants, number of heads, and grain yield. This result demonstrates that it
is possible for farmers to store the seeds for up to 3 days if they are not able to utilize
all the seeds on the day of priming. This makes seed priming a more flexible approach
than if all the seeds need to be sown immediately following seed priming.
3.3 Environmental Conditions on the Response to Seed
Priming and Microdosing
It was important to determine the environmental conditions under which seed priming and microdosing would perform best. The relative yield between treatments
(T2, T3, and T4) and control (T1) was calculated; if it was above one, this would
indicate a positive effect of the treatment (priming and microdosing) as compared to
the control. This relative yield for each treatment and site was plotted against yield
of the control for the site. The yield of the control can be considered as an indicator
for the environment at the site as it is determined mainly by rainfall, soil conditions,
disease, pest, and weed pressure. The regression analysis showed that the relative
benefit of seed priming and microdosing was reduced when environmental conditions become more favorable (higher yields in the control).
In sorghum, there was hardly any effect of seed priming and microdosing when
the yield in the control was above 2000 kg/ha. Below a sorghum yield of 900 kg/ha
in the control, there was a good response to seed priming and microdosing. Between
900 and 2000 kg/ha, seed priming and microdosing had a positive effect, but the
effect was more variable. These results show that seed priming and microdosing are
technologies that are mostly suited to marginal environments (Figs. 1, 2, and 3).
The result for pearl millet showed that, as with sorghum, there is a decline in relative
yield between the treatment and the control when the yield of the control is increased.
As Figs. 4, 5, and 6 indicate, there is a consistent response to these treatments when the
yield in the control is below 500 kg/ha. Above 500 kg/ha in the control, the response in
comparison to the control is still evident, but the effect is more variable.
However, when plotting the yield in the control against the absolute yield
increase, no clear relationship was apparent (figure not shown). The same increase
in yield (kg/ha), as a result of the treatment, can therefore be expected across different yield levels in the control.
A. Coulibaly and J. B. Aune