On Fri, 16 Mar 2007 17:22:57 -0400, Bill Truesdell <bhfarms@SUSCOM-
MAINE.NET> wrote:
>There is just too much lacking in what is available in the study to make
>any pronouncement other than the researchers found more bees in the
>organic field than they did on the GM field. To step further than that
>is speculation and not science.

Speculation is the launching point of forming a hypothesis and, this, is 
an important step in science.  Although I think Bill rightfully draws our 
attention to the limitations of extending the findings of a study too far, 
I think some of his other concerns can be addressed by reevaluating the 
outcomes of the experiment. 

While it is true that the organic fields used B. rapa, it is my 
understanding that this is typical of organic canola production.  
Furthermore, there was a third group, which I made mention in a previous 
post, conventionally grown canola (ie pesticide and herbicide use, but no 
GM varieties).  Both the conventional and GM fields were B. napa.  

>For example, the GM Canola was probably B. napus which is self
>pollinating, (http://www.canola-council.org/gs_stage6.aspx), while the
>organic farm was more likely B. rapa which requires pollination and you
>can grow your own seed (something organic farmers like in a crop). B.
>rapa is nothing more than a cultivated weed and easily grows wild. If
>you have less pollinators for B. rapa you will have a problem, but not
>for B. napus.

It is important to note that the opposite findings were observed in the 
study... despite the organic fields having a cultuvar that is more 
DEPENDENT on pollination, they had a smaller pollination deficit than the 
SELF-pollinating GM or conventional B. napa.  If I understand the problem, 
the organic field cultivars overcame their self-pollination handicap and 
still maintained a lower pollination deficit compared to the other two 
groups. 

In the authors words:

"...we found no pollination deficit in organic fields (me: in contrast to 
the GM and conventional fields). Since organic canola was B. rapa, we were 
not able to make direct comparisons of absolute seed numbers with GM and 
conventional canola. However, because B. rapa is self incompatible (Ohsawa 
and Namai 1987, Mishra et al. 1988, Zuberi and Sarker 1992), we predicted 
that B. rapa would be more vulnerable to pollination deficits under 
inadequate pollinator conditions. Lack of difference in seed number 
between open-pollinated and supplementally pollinated flowers in organic 
canola was likely a result of sufficient bee numbers to produce full seed 
set."

>B. napus sets fewer but larger seeds than B. rapa and also has a shorter
>bloom for each flower. So you have a natural reason for fewer seeds that
>has nothing to do with a pollinator. Fewer seeds does not mean less
>yield since they are larger.

Remember the measure was not absolute number of seeds, but pollination 
deficit, which I defined in a previous post as the number of seeds in a 
pod set by open pollination compared to the number set when the pods were 
manually pollinated (theoretical maximal pollination).  Despite being more 
dependent on pollination, they had a lower deficit.  Furthermore, the 
conventional cropping system had less of a deficit than the GM system, and 
both systems used B. napa.

It should also be noted that the authors fit a relatively tight 
relationship between pollinator abundance and pollination deficit, 
irrespective of cultivar, which is yet another piece of evidence that 
suggests differences in pollinator abundance among the cropping systems is 
largely explained by considerable variation in observed deficits. 

>I would love to see the full study done on bees preferring non-GM crops
>since all I can find are abstracts which leave more questions than
>answers. Especially since they talk of both B. napus and B. rapa. The
>latter piqued my curiosity.

I think the experiment Bill proposed would most certainly add to our 
knowledge of this new area of study.  A diversity of studies are necessary 
to fill out any picture. Nonetheless, I would warn about the "abstract 
nature" of uncoupling "variety" from "cropping system", as the latter may 
ultimately be more important than the former in what growers will 
experience in the world.  In the concrete world variety and cropping 
system are never uncoupled: GM varieties are tied to cropping system by 
their very nature. Rather than cloud the picture, I see this study 
describing a strong difference across cropping systems and it begs to be 
replicated... continued findings of this type would support the hypothesis 
that GM cropping systems require supplemental pollination to maintain high 
yields.

>It can get even more confusing if you factor in the number of male to
>female plants, diversity of plants and weedy areas nearby. Plus,
>micro-climates can have great effect on yields, especially on B. napus.
>There is an abundance of studies available on canola (mostly from
>Canada) that show a multitude of thing that can affect yields and seed 
set.

This is an old problem, going back to the beginning of modern 
agriculutural science.  Agricultrual science always requires replication 
across multiple sites and years to establish a solid foundation from which 
to produce something of use to farmers. If multiple studies result in a 
very contextual outcome (eg pollination only benefits in wet years and in 
XYZ soils) then the finding may be of limited use.  After an initial 
study, however, it is okay to speculate what you might find next... this 
is science... it is just important to heed Bill's warning not to form 
policy on just one study.  If I suggested this be done in a previous post, 
or have been percieved to have wrote this, then I am out of line.

Adony 

PS I most certainly was speculating that pollination, in some instances 
might be a very sustainable way to increase inputs.  I hope I made it 
clear that I don't really know if it is, but that I think it could be a 
useful contribution to sustainable agriculture to look into this problem.  
I hope most of you caught Allen's good post warning some of the pitfalls 
of this logic... organic apple production being a prime example of where 
over pollination will significantly hurt the orchardist's profitablility, 
by requiring manual thinning.

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