Vernalization ?

[Clive]

how cold for how long does soil temp have to be ?

seem to recall sub 9deg c for 3 weeks ??

I'm sure with the amount of WW that went in the last week or so it will be a question a lot of farmers would like to know the answer to ?

 

[Rob Holmes]

I thought i was air temp after germination, don't know figures though

 

[John 1594]

drilled mine second week of feb, its chitted, but still isnt through yet, if weather stays like it is (unlikely i know!) then we will have a go at getting some spring barley in at the end of the week, if we do it wouldnt suprise me if thats not up and away before the wheat gets out of bed!

 

[dragonfly]

I would like some more information if possible. Or even details or websites of where to find information.
Its a subject often mentioned, but very rarely quantified!

 

[Chickcatcher]

Below is a responce received from an enquiry regarding Panorama of which I have sown 64 Ha end of February.
Thank you for your enquiry to our website. I attach a list of our latest safe sowing dates for winter wheat varieties and you will see that we suggest Panorama is OK until the middle of March.

It is very difficult to quantify the requirement and the timings because individual varieties vary quite significantly. Some sources suggest the process can start once germination is underway, others say later when the plant starts to tiller.

In our growth room work with new varieties (often with an unknown vernalisation requirement) we sow seeds in pots and grow them at 4 degrees C for 8weeks, which is usually sufficient chilling for most varieties.

Panorama is a cross between Xi19 and Solstice, the latter having a very low requirement. We have sown Panorama in early March at our trial site in north Lincolnshire in a number of seasons and it has been fine.

I hope these comments help.

 

[Chickcatcher]

The Attached for above

SUGGESTED LATEST SAFE SOWING DATES FOR LIMAGRAIN WINTER WHEAT VARIETIES​

Presented below are the suggested latest safe sowing dates for Limagrain winter wheat varieties. The information is taken from a number of sources which have been combined to compile the table:



· The HGCA Recommended List

· Limagrain in-house trials, sown at Rothwell in north Lincolnshire

· Genetic marker work indicating the presence of genes (Vrn-1A) which control vernalisation

· The Limagrain breeding team’s experience with the varieties.

VARIETY​

SUGGESTED LATEST DATE​

Xi 19

END MARCH​

​

Claire

MID MARCH​

Panorama

MID MARCH​

​

Gravitas

END FEB​

Invicta

END FEB​

Istabraq

END FEB​

​

Alchemy

MID FEB​

Einstein

MID FEB​

Horatio

MID FEB​

Myriad

MID FEB​

Edgar

(MID FEB)​

Panacea

(MID FEB)​

Zulu

(MID FEB)​

​

Cassius

END JAN​

Crusoe

END JAN​

Revelation

END JAN​

Solstice

END JAN​

Stigg

END JAN​

Evolution

(END JAN)​

[ ] = limited data

​

The suggested date is the latest sowing time for the variety to receive a sufficient cold period to induce flowering.



Conditions after sowing very much govern whether a variety will switch from vegetative growth to reproductive growth later in the season and ultimately flower. It is very much influenced by site specific factors such as field location (e.g. the south vs north of the UK), altitude and aspect (e.g. north or south facing fields).

 

[Nearly]

I've 4t of Conquerer which may go in this week in the bald spots. Undecided but it's one of the later ones on here.

http://www.niab.com/news_and_events/article/260

 

[jpd]

open to correction
between 4 to six weeks sub 8 c
it switches a pair of genes to cause the plant to flower
i wonder does 6 weeks in the shed sub 8c count?

 

[Big Blue Yonder]

heard rumours about sub 8c in shed but no one willing to put hand up

 

[wildnwoolly]

I know of a couple of farmers that have refrigerated 7.5t lorries and they had the seed sitting in then for a week before sowing. Dont know what temperature they were sitting in.

 

[Clive]

I know of a couple of farmers that have refrigerated 7.5t lorries and they had the seed sitting in then for a week before sowing. Dont know what temperature they were sitting in.

cant see that working - I think the seed has to have started growing surely ?

 

[Rob Holmes]

I asked my agronomist, he said it's needs to have germinated

 

[Renaultman]

I've just drilled some Santiago. We're due frost tonight which will probably be to early. My agronomist thinks that we are at least a month colder than the South where the recommendations are based and the seed is HS and if I didn't drill it I would almost certainly destroy it as I would like to think that this harvest's must be better quality.
As someone else has already said, worse case scenario It's sileage.

 

[TWF]

open to correction
between 4 to six weeks sub 8 c
it switches a pair of genes to cause the plant to flower
i wonder does 6 weeks in the shed sub 8c count?

Similar to what I thourght 3 weeks Below 7*c .

 

[Fuzzy]

I know of a couple of farmers that have refrigerated 7.5t lorries and they had the seed sitting in then for a week before sowing. Dont know what temperature they were sitting in.

Surely that has almost the opposite effect (and completely pointless !!), does it not need to be warmish for the seed to germinate in the ground ??

 

[Ramrod]

Don't know where I read it last week but it said, 2 weeks of 5c after chitting.

 

[wildnwoolly]

Surely that has almost the opposite effect (and completely pointless !!), does it not need to be warmish for the seed to germinate in the ground ??

Im just a simple peasant and not a wheat baron. In Scotland come February your really pushing it for wheat the ground is cold and wet most years. I think one of the reasons behind it is the seed is primed ready to go when it hits the ground instead of coming out the shed into a cold seed bed and getting a shock and just sitting there. Im just a drill man but I would say the stuff sown this way comes through quicker than other stuff. Not very scientific just saying whats been tried.

 

[warksfarmer]

What I drilled (xi19) 10 days ago is now all chitted and the average temp over the last 10 days according to the weather station has been 3 degrees with a peak of 12 degrees yesterday.

 

[wellingtonfarmer]

Theoretically speaking If you plant say Santiago which is end jan variety, and you plant it in a frost mid jan, and because of the cold weather it was frosty until end feb/march, are we saying that the crop won't of vernalised as it probably wouldn't of germinated as it would of been to cold?

 

[Wombat]

My understanding was that vernalisation started the moment the seed went active, so enough moisture to start the germination procedure. Looking at the forecast our Santiago might be ok, fingers crossed