HYB: 201 -- Quarterbreds
- To: Multiple recipients of list <i*@rt66.com>
- Subject: HYB: 201 -- Quarterbreds
- From: S* M* <7*@compuserve.com>
- Date: Tue, 13 Jan 1998 10:16:31 -0700 (MST)
Sharlyn Rocha wrote:
> For your 201 class, I would be especially interested in ideas f=
or
> crossing arilbreds with TBS. Is there any way to predict what colors
you
> will get? =
Yes, although it's somewhat more =
complicated than with TBcrosses and
there are often surprises in the seedling
patch.
> We learned a lot with Tom's chart on crossingTBS. =
REVIEW ASSIGNMENT, for newcomers:
Get Tom's chart from the archives.
The title was "TB color genes made easy".
The date was 7/17/97.
His chart provides an easy-to-follow triage:
x At least one dose present
o None can be present
blank Unknown
For projecting recombinations over several
generations, I find it helpful to describe each
each trait with a quartet of symbols that =
represent the four doses in a tetraploid. I
also like to use a question mark instead of
leaving a field blank.
To illustrate, I'll expand Tom's first example --
a blue or violet self:
V V ? ? ?
I i i i i
I-s is is is is
Y y y y y
A ? ? ? ?
H ? ? ? ?
T ? ? ? ?
PL PL ? ? ?
pl ? ? ? ?
HOMEWORK:
Compile a similar chart for SOSTENIQUE.
It's somewhat more complicated, but I
want to use a real-life example. =
> Are some
> arilbreds easier to cross than others? We only ended up with one cros=
s
> that took with our arilbreds.
The TB x AB cross is a wide one, which
normally produces fewer seedlings than a
TB x TB cross or a cross of two halfbreds.
> A few arilbreds seem to look more like fancy TBS. Is there anywa=
y
when
> crossing to predict which side of the family the seedlings will take
after?
The aril content is the best indicator.
Those that are only one-quarter aril and
three-quarters TB naturally take after the
TB side of the family. =
Sounds like our first topic should be how
to select parents that will give seedlings
with aril characterstics.
Sharon McAllister
73372.1745@compuserve.com
