Green Canola

[lobo]

We farm north of Saskatoon, which this year was affected by serious drought conditions. We seeded Round-up ready canola this year. We swathed this year at the same stage we do every year, however, our canola sat in the field a long time before we were able to pick up because of green color in the seeds. In my regular commute between various communities I noticed that there was alot of canola left late in the fields this year. I also noticed that others were able to pickup within days of the swather. Can someone offer an explanation, or is the variety that we selected this year susceptible to green seeds. The variety we used 45A54. Did anyone else have problems with Roundup-ready canola?

[pthomas]

You mentioned the key word as far as green seed goes - drought. Normally most of the green seed problems in western Canada come from three things:
1) frost that damages the enzyme system that degreens the seed by breaking down the chlorophyll. Even a light non-lethal 0C frost can have a detrimental effect on the enzyme system if the seeds are at a high moisture content. Frozen canola seeds rarely change color after the frost. There can be a bit of sunlight bleaching but usually only on the outer part of the swath.
2) Alternaria blackspot disease. Disease on the pod infects the seed and disrupts the enzyme system so the infected seed stays green.
3) canola fields swathed early which then dry down rapidly resulting in the enzyme system being hung up without enough time to clear the chlororphyll before the enzymes stopped working. The enzyme system needs moisture and temperature to do its job. Seeds at 20% or less moisture are basically dormant with very little metabolic activity. Canola plants that are under drought stress at maturity have a greater probability of having green seeds. Once the seeds have dried down to less than 20% moisture there will be little change in enzyme activity unless the seeds are rehydrated. Leaving canola with green seed in the swath for a long time may result in a decrease in the amount of green seed. For a significant change in percentage of green seed the swaths will probably have to be very wet for several days so the seeds actually get rehydrated enough for the enzyme system to speed up enough to clear chlorophyll.

With regard to variety - there could be a problem with certain new varieties. For example the variety "Cyclone" had a green seed problem. Last year we had a big problem with green seed in Alberta, however, as most of it was the result of a light frost there was little difference between varieties. To-date I have not been able to identify any of the over 200 varieties available as having a worse problem with green seed other than Cyclone.

Phil Thomas
Canola Consultant

[winston]

I farm in SW mb. lots of problems with green seed everywhere with no great diff between varities..but the smart varitie was better this year however it was the one with the most green in it last year