Kirjoittaja Aihe: Some tips for chili crossing  (Luettu 8196 kertaa)

Poissa MelT

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Some tips for chili crossing
« : Huhtikuu 09, 2010, 04:01:31 ap »
I don't have much to add to Fatalii's fine article
http://fatalii.net/growing/index.php?option=com_content&task=view&id=35&Itemid=54
but I do have a few suggestions that some may find useful.

Tools
Fine-tipped forceps are important for the delicate work of dissecting out the anthers
from an unopened chili flower bud that will be used as the female for the cross.  I have
several stainless-steel watchmaker's forceps in my biology laboratory toolkit: 



When they were new they were very fine-tipped, but most of mine have been broken and
reground over the years.  They're still quite adequate for removing anthers from even
tiny flower buds such as those of C. chacoense.  (The wires in the image are connected to
short lengths of brightly-colored plastic flagging tape to make them easy to find if dropped
in the garden [I lost one for most of a season]) 

Also useful is an inexpensive  pair of nonprescription reading eyeglasses for the easier
dissection of small flower buds.  At least, my eyes now seem to need them although I'm
pretty sure they didn't before.

I advise attempting multiple crosses for each hybrid combination.  It is
possible that only a few hybrid pollinations out of many tries may succeed in
producing fruit and seed.  Fruit set on a particular plant may be poor during part of
the season [night temperatures, perhaps, or some other issues with the physiological
state of the plant], so repeating a failed cross at multiple times may help.

It's also a good idea to try reciprocal crosses of each pair of parents [i.e., try using
each of the two parental strains as both the pollen parent and the seed parent in
different pollinations].  It can affect success as well as the resulting offspring.

Using varieties with large numbers of flowers at a time is advantageous.  Wild
species and primitive varieties like "Duke Pequin" are good in this way.  One can do
many simultaneous crossing attempts with a single plant.

It's surprisingly easy to do many crosses in a short time. The first critical step is to
remove the unopened anthers [the structures with the pollen sacs at the tips of the
stamens], from a full-sized but unopened flower bud without damaging the ovary, style
and stigma [the flower's female bits].  It becomes easy to recognize those flower buds
that are likely to open that day, and it's also fairly simple to slit or tear open the
corolla [petals] with the forceps and pick out the anthers. 

Instead of using a cotton swab or a brush, I have generally been using large amounts of
pollen in each pollination, often using an entire anther sac picked out of a newly-opened
flower of the pollen parent, or even a whole picked flower, to load the stigma with a
visible mass of pollen.  The tip of the fine forceps, or the plastic toothpick of a Swiss Army
Knife, or some similar object can be used to scrape pollen from an anther sac and to deposit
a visible mass of pollen onto the recipient flower's stigma.
   
Similarly, chile flowers such as "Duke Pequin" will leave a visible deposit of pollen on
the back of a fingernail or thumbnail that can then be carefully deposited on a
stigma of an emasculated flower bud.

Unlike a brush or swab, a thumbnail or forceps or plastic toothpick are easily cleaned
with an alcohol wipe to be ready for the next pollination. 

Labeling
One suggestion I'm pleased to share is a very simple way to more easily label numerous
cross-pollinated flowers and fruits, something that is especially useful if one is doing
multiple different crosses on a single plant.   

I salvaged a few meters of discarded telephone cable.  Inside the plastic sheath the
cable consists of 50 slender copper wires with waterproof plastic insulation, each wire
colored and banded differently from all of the others:


A short length can easily be clipped from one of them and twisted into an open loop
around each  pollinated flower's stalk as a simple way to label each cross.  I really never
needed more than a few different colors per female parent plant, but the potential is there
to distinguish pollinations by many different pollen parents.  For example:

"Wiri wiri" flowers recently pollinated and labeled showing two different crosses. 
The wire loops are lightweight and make simple waterproof labels:


Rim of the same "Wiri wiri" plant's pot with supply of more wire for
additional crosses [WB = "Wild Brazil"; DP = "Duke Pequin"]:


An unripe "Wiri wiri" fruit labeled as being from a pollination by "Duke Pequin" pollen.


I haven't been putting protective paper bags over pollinated flowers, but this
might be a good idea.  I have lost a few ripening crosses to birds, but nothing
irreplaceable.

Proof of success comes with the next generation, when seedlings first become
detectably different from their mother plant.  This will be easier to tell with
crosses between widely-different  parents than between closely similar forms.

Poissa Michael

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Vs: Some tips for chili crossing
« Vastaus #1 : Huhtikuu 27, 2010, 01:54:21 ap »
Extremely nice written. Thank you for excellent input!!