Farm saved or certified seed?
Research shows the yield losses of growing farm saved hybrid canola compared to certified seed are about 13 percent on average.
November 19, 2007 By Donna Fleury
Although some producers choose to use farm saved seed rather than certified,
research shows that can be a risky undertaking, particularly with hybrid canola.
The perception seems to be that there is little difference between the certified
and farm saved open pollinated or hybrid canola varieties, and that strategies
such as increasing seeding rates or seed size can compensate for any differences.
However, findings of a recent research study at Agriculture and Agri-Food Canada
do not support those ideas.
Led by Stu Brandt, crop management agronomist at the Scott research station,
researchers set up trials at six locations in Saskatchewan and Alberta in 2004
and 2005. "We wanted to determine if there is a reduction in yield potential
of the F2 generation, which represents the second generation seed from high
yielding hybrids, compared to the actual hybrids (F1)," explains Brandt.
Some have suggested that yield reductions could be as high as 50 percent, so
researchers wanted to establish what average losses might be over a broad range
of conditions throughout the canola growing region. "We also wanted to
determine if this relationship is similar for both hybrid and open pollinated
Brandt emphasizes that it is important to understand the differences between
open pollinated and hybrid cultivars. Open pollinated varieties are based on
pure breeding lines that reproduce themselves from one generation to the next
with a lot of precision. Open pollinated varieties are also genetically stable
from one generation to the next. However, hybrid varieties are the product of
a cross between two genetically dissimilar parents. Therefore, the result is
the F1 hybrid generation is very uniform, but the F2 is virtually all segregating
and none of the F2 plants are genetically the same as F1. "Consequently
you lose hybrid vigour in F2 plants and likely a lot of other useful characteristics
as well, such as herbicide tolerance in a proportion of the F2 plants."
To address questions about increasing seeding rates, and selecting larger sized
seed as a way to compensate for F2 seed and hybrid vigour, researchers compared
normal seeding rates and two times the seeding rate. "We also screened
the seed for sizing, using a 5Ú64th screen to remove any smaller seed,"
says Brandt. "The seed weights on all of the seed lots were 4.75 grams
per thousand (g/1000) seed weight for certified seed and 4.33g/1000 seed weight
for farm saved F2, which is a very large seed lot. We set the bar very high
for all seed lots to make sure the quality of the seed was the same between
generations. All of the seed lots in the trial exceeded 90 percent germination."
Overall, the seeding rate and seed sizing did not really make any difference.
In a few trials, three of 17, there was a small increase in yield at the high
seeding rate, but that was in trials with a lot of weed competition. "The
overall yield difference between the two seeding rates was less than one bushel
per acre," says Brandt. "In comparing seed size, using the larger
seed did not improve the performance in any of the trials."
With the open pollinated varieties, there were no statistical differences between
certified and farm saved seed. All seed was treated with Helix, however flea
beetle damage was very low in all trials. "The results were pretty much
what we expected of an open pollinated variety, with the range being from three
bushels per acre less to three bushels per acre more for farm saved compared
to certified," says Brandt. If seed quality is high, and flea beetle pressure
low, then producers may see similar results.
"However, when comparing certified to farm saved hybrids, the resulting
yield losses were significant," says Brandt. The farm saved hybrids yielded
as much as 10.5 bushels per acre less than certified. Overall, the yield loss
from using an F2 from the hybrid was about 13 percent on average between all
of the comparisons. "The differences in yield tend to be larger when the
crop is under stress, which is consistent with what we're learning about hybrids,
and that the real benefit of hybrid vigour appears to be most evident when the
crop is under stress."
Some of the most effective seed treatments are only available for use on certified
seed, and for 2006, this includes Gaucho. "So, for farmers, the farm saved
seed issue is confounded with the seed treatments," explains Brandt. "For
this reason, we also looked at farm saved seed with various seed treatments
compared with certified seed treated with Helix." The list included Helix
and Gaucho, which contain insecticide and fungicide, as well as Foundation Lite;
a fungicide only treatment. Certified hybrid seed treated with Helix yielded
four to 28 bushels per acre more than farm saved seed treated with Foundation
Lite, averaging 11 bushels per acre or 22 percent more over eight locations
during 2004 and 2005. A similar comparison of certified plus Helix with farm
saved plus Gaucho, which was only done in 2005, showed a seven bushel per acre
(range of four to 12 bushels per acre) advantage for certified.
Another concern with F2 hybrids is the loss of herbicide tolerance in some
plants, which may result in greater crop damage. There is also the problem with
the number of plants that produce no viable pollen (male sterile). These plants
are part of the process of developing hybrids and although they do flower, they
will only produce a few seeds if there is enough pollen transfer from adjacent
plants. "However, because these plants don't generate a normal seed load,
they tend to continue flowering later in the year and often have a lot more
green seeds than other plants," explains Brandt. "We don't have a
good understanding of the extent of this problem at this point, but there is
some potential for an increased risk of downgrading due to green seed."
The quality of the seed is another major factor to consider. "Although
we used the highest quality seed for the trials, there is no guarantee of quality
if you buy uncertified seed," says Brandt. Buying certified seed is assurance
of quality and with hybrids, it is an assurance of the quality and the traits
included in the F1 generation.
Similar research conducted in North Dakota has shown yield losses associated
with farm saved seed were much higher, and occurred with both open pollinated
and hybrid varieties. The research also showed that losses tended to be highest
when environmental stress limited yield. In North Dakota, the flea beetle protection
was more critical.
The bottom line is that trying to save your own seed really is not worth the
reduction in yields, the increased costs of trying to compensate with higher
seeding rates or seed size. Using F2 hybrid seed is like gambling on genetic
traits and which ones might appear in the farm saved generation, as compared
to what is guaranteed in an F1 hybrid.
"Our overall findings show that in almost every case, the savings associated
with using farm saved seed would not offset the yield losses, even with $5 per
bushel canola," says Brandt. This research was conducted in partnership
with the Alberta Canola Producers Commission and the Saskatchewan Canola Development