Re: Re: HYB: burrito germination experiment
iris@hort.net
  • Subject: Re: Re: HYB: burrito germination experiment
  • From: C* C* <i*@aim.com>
  • Date: Sun, 19 Dec 2010 14:41:39 -0500
 My current data indicates that there are two requirements for germination.

1) Removal of germination inhibition chemical.
2) stratification


Removal of anti germination chemicals can occur in burrito, but hit and miss.
In back of toilet bowel would work well, but soaking and rinsing for 5 days is
all that needed.

Stratification needs to be in moist conditions at 4C or about 38-40F, with
proper access to oxygen..? 6 weeks should be enough.

At 3 months I had nearly 100% germination . (actually 96%. There were only a
few odd seeds not germinated at this time.?


Cold temperatures reduce germination . Bearded Iris seeds seem to be the only
exception. I don't know of any other species? that can actually germinate at
statification temperatures. Most? species require? bringing seeds into room
temperature for? germination. And for all species, 6 weeks was more than
enough. Lots of experimental? data in research literature for this.

For beardless iris, there was very little germination? in fridge. But nealy
100% when placed in soil after statification.


Linda may need more then 6 weks, but I suspect her? experiments lacked? the
necessary conditions. that is? some lack of oxygen in burritoed seeds, and?
lack of proper? removal of anti germionation chemicals in others.??

What is needed for time in burritoed? seeds is different? then what I did with
removal of anit-germination chemical and? moist stratificatiuon, with oxygen.


Chuck Chapman














-----Original Message-----
From: Linda Mann &lt;lmann@lock-net.com&gt;
To: iris@hort.net
Sent: Sun, Dec 19, 2010 10:13 am
Subject: [iris] Re: HYB: burrito germination experiment

   I've done it both ways - advantages and disadvantages to both methods.?
?
 Advantages to potting all seeds as soon as some start germinating:?
 -Fewer pots to handle?
 -Less to think about/remember to do?
 -Less time spent checking burritos every few days (which can be very  time
consuming with a lot of burritos)?
?
 Disadvantages?
 - Pots contain ungerminated seeds, some of which need more chilling (40  to
45oC) while my TB seedlings need somewhat warmer temperatures to grow  fast
(50 to 60oC when still sprouting, higher once green and growing).?
?
 The biggest advantage to picking out individual seeds as they germinate  is
that the growing seedlings can be pushed to grow faster, so they will  be big
enough to line out in late March (maybe under row covers) & early  April
before I get busy with bloom season.?
?
 This year's pots will all go out in the sunporch, where this time of  year,
night time temperatures are usually cool enough to continue  chilling, while
daytime temperatures are warm enough to stimulate  sprouting.  Once the first
flush of sprouting is over (i.e., no new  sprouts for a couple of weeks), I'll
pick out the sprouts, put the pots  with ungerminated seeds outdoors, bring in
last year's pots from crosses  that looked promising this year (i.e., IMM X
RED ROCK CANYON).?
?
 In the past, I usually wait about a month after last sprouts have shown
before putting pots of ungerminated seeds outdoors for more chilling,  but if
it's as cold outdoors in Jan as this Dec (unusual), the sunporch  will be cold
enough to keep them there.  Hopefully enough warmer  directly under the lights
to stimulate growth on the sprouts, cold  enough on the floor to stratify
seeds. Ideal world ;-)?
?
 That's the plan anyway.?
?
 Because past experience has repeatedly shown more than one flush of
germination, I disagree with Chuck on this - they are not all ready to
germinate at the same time.?
?
 &gt; Why are you potting them all up now rather than putting them back in
the?
 &gt; fridge to continue germination?....?
 &gt;  I thought people said they were putting them?
 &gt; in and out the frig until everything sprouted--picking a few out each
time.?
 &gt; Betty W.?
?
 Prior experience has demonstrated (repeatedly) that for my crosses, 6  weeks,
even at the warmer, more optimal stratification temperature,  simply isn't
enough.  And some crosses need a second cycle to germinate  - 2 or 3 months
stratification, followed by warmer temps (and maybe  drying?), then another
period of stratification.?
?
 Most of the early experiments on timing that I did were with seeds that  were
first dried, then soaked (panty hose in toilet tank method), then  burrito'd
at a colder, less than optimal (35 to 40oF), fridge  temperature than I'm
using now.  (check photos archives for graph of  optimal temperature for
chilling - fruit tree buds, not seeds, but seems  to be the same for both)?
?
 No idea how long the second period needs to be because I haven't done  the
experiments.  By that time (the second year), the seeds have all  been in pots
outdoors since the preceding spring.  I usually bring them  in sometime in
January, by which time they have had 2 or three months of  another round of
chilling, this time outdoors.  For this second round,  they might only need a
month (or 6 weeks), but that's too early for my  purposes, so I haven't
experimented.  By that time, I usually have some  seedlings from each cross
the prior year to evaluate plus am handling a  bunch of new crosses.?
?
 So, bottom line, 6 weeks of stratification may be plenty for some  crosses,
but nowhere near enough for others.  Obviously, I only have  experimented with
a limited bunch of genes here.    I have no idea about  others.?
?
 Some of the info I read about germination inhibitors way back when said  that
environmental conditions while seeds are developing can affect  germination
requirements in some species.  Seems like the article was  referring
specifically to heat and drought.  No idea if that applies to  irises, but
something to keep in mind.?
?
 &gt; Personally I would think 6 weeks in fridge (after soaking) and then
planting?
 &gt; should be all that is needed.?
 &gt;?
 &gt; Chuck Chapman?
?
 Linda Mann east TN USA zone 7?
 sun!!?
?
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