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Author Topic: Breeding interspecific hybrids - Capsicum spp.  (Read 18999 times)

PhytoFlight

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Breeding interspecific hybrids - Capsicum spp.
« on: September 12, 2013, 12:27:51 AM »

I've gathered some resources particular for Capsicum hybridization, although other interspecific hybrids are very interesting and I'd like to manage to do some. Attached are relevant pdfs.

I'm very interested in this, but have no practical experience regarding the materials, and I'm usually in unicellular organisms or animalia in my research career. Plant biology is a brave new world! Does anyone have experience with trying to produce hybrids of separate species, perhaps with a given metabolic product in mind?

This is the most helpful resource I've found regarding making interspecific hybrids.

http://plantbreeding.coe.uga.edu/index.php?title=5._Polyploidy#Implications_of_Ploidy_in_Plant_Breeding

Quote
Another breeding strategy that utilizes the reproductive superiority of polyploids is bridge crossing. When sexual incompatibilities between two species are due to ploidy levels, transitional crosses can be carried out followed by chromosome doubling to produce fertile bridge hybrids. This method has been used to breed for superior tall fescue grass (F. arundinacea) from Italian ryegrass (2n=2x=14) and tall fescue (2n=6x=42) by using meadow grass (Fescue pratensis) as a bridge species (Fig.5.7) (Acquaah, 2007). The same principle has been applied in fixing heterozygosity in hybrids by doubling the chromosomes in the superior progeny (Comai, 2005).

This seems to be the ideal trick. It could require Embryo Rescue, but it looks more doable for the amateur than inserting genes into a plant. (that being said, doing so would not be uninteresting - if the required set of genes for a full pathway were inserted along with appropriate regulatory elements and then coupled to survival/cell fitness in such a way that the genes were expressed, a plant could be made to produce a given compound. There are even some commercial algae companies synthesizing organic intermediates using the KEGG database's biochemical reaction networks as a 'toolbox' for doing so.)

This also seems relevant: http://www.as.wvu.edu/~kgarbutt/QuantGen/Gen535_2_2004/Polyploidy.html

Found elsewhere:

Quote
Reproductive characterization of interspecific hybrids
among Capsicum species
[[Attached]]


C. annuum and C. baccatum are considered species
belonging to different gene complexes in view of the
crossability.
However, fertile hybrids were obtained
between the species C. annuum var. annuum (sweet or
hot pepper) and C. baccatum var pendulum with pollen
viability exceeding 90 % (Table 4).
On the other hand, the viability of the reciprocal combinations was low, around
35 %, and combinations between C. baccatum var. baccatum
x C. annuum var. annuum resulted in hybrids with very
low fertility as well (Table 5), with an average 35 % of
viable pollen grains. C. annuum and C. baccatum belong
to different gene complexes, and the results reported here
were not expected.
An interesting observation was the high
pollen viability when C. annuum was used as female
parent, since the pollen viability of such combinations
was high. According to Shifriss (1997), hybrids between
C. annuum and C. baccatum have varying degrees of male
sterility, according to the

. . .
In conclusion, some combinations are possible and
fertile, enabling the gene transference between species,
whereas the fertility degree of other combinations can differ,
indicating partial or complete male sterility, assessed here
based on the pollen viability.

The conclusion was also
drawn that infertility is a postfertilization barrier since the
establishment of hybrid combinations is possible, but
breeders will have to apply strategies as described by Yoon
et al. (2006), to continue the breeding program of Capsicum.
« Last Edit: September 12, 2013, 12:33:15 AM by PhytoFlight »
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Mandrake

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Re: Breeding interspecific hybrids - Capsicum spp.
« Reply #1 on: September 12, 2013, 12:48:02 AM »

Many thanks for the post.

Most people here, inlcuding myself, will not have your expertise considering your field - let alone the practical experience. But I think it's better to raise the bar and bring good information that will make people read and learn more if they are interested.

Considering the "technical" level of the topic and the general aim, I'm moving it to the Botanical Information forum the new Crossbreeding and Hybridisation subforum is where it belongs :)

Thanks again and welcome.

Mandrake 
« Last Edit: September 18, 2013, 08:29:49 PM by Mandrake »
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Auxin

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Re: Breeding interspecific hybrids - Capsicum spp.
« Reply #2 on: September 18, 2013, 08:27:45 PM »

A few notes I keep for myself, relevant to both intra- and interspecific hybridization, though typically based on intraspecific crosses unless otherwise indicated:

Pepper orientation:   Pendant- Dominant   Upright- Recessive
---------------
size is variable
---------------
Yellow is fully recessive to red
Gold color is recessive to red
orange is recessive to orange-yellow
two independent, fully-recessive genes are necessary to achieve a green when ripe coloration in peppers. One is the cl gene, which retains chlorophyll ("prevents the complete degradation of chlorophyll") and the other is the y gene (y+="red pigment lycopene", y=yellow or orange).
Here's the down and dirty of the 4 combinations of these genes and their phenotypes (what you see):
Red mature fruit: y+/y+, cl+/cl+
Yellow mature fruit: y/y, cl+/cl+
Brown mature fruit: y+/y+, cl/cl
Green mature fruit: y/y, cl/cl
---------------
Marbled variegation is recessive
---------------
'Umbrella' plant form relies on three recessive genes
---------------
Capsaicin content - additive, dominance and dominance x dominance components found to be significant; however the magnitude of additive component was higher
---------------
In simplest terms earlyness is dominant over lateness (trait is a composite of dominant, codominant, and additive variables)
---------------
Anthocyanin in plants, flowers, and fruits incompletely dominant. (A. in the style or filament can operate off separate genes- D/R character of both traits unknown). There is an 'intensifier' gene,   D/R character unknown
---------------
C. pubescens corolla anthocyanin produced by a single dominant gene
---------------
Tiny warty bumps on stems, leaves, and cotyledon can be genetic
---------------
Easy pod/calyx separation gene is incompletely dominant.
---------------
pointed fruit apex not fully dominant to blunt
---------------
Pointed apex dominant over indented apex (single gene)
---------------
Non-indented calyx attachment dominant over indented calyx attachment (single gene)
---------------
Yellow corolla spots of C baccatum var. pendulum and C. praetermissum act as single gene dominant in crosses with other species.
---------------
The mode of seed color inheritance in Capsicum was studied via an interspecific hybridization between C. pubescens Ruiz and Pav. (black seed color) and C. eximium Hunz. (yellow seed color). Black seed color was dominant over yellow seed color. The F2 segregation pattern showed continuous variation. The generation means analysis indicated the presence of a significant effect of additive [d], dominance [h], and additive x additive [ i ] interaction for seed color inheritance. The estimate for a minimum number of effective factors (genes) involved in seed color inheritance was approximately 3.
---------------
a single dominant gene, C, is required for pungent genotypes to produce capsaicinoids.
---------------
Crosses between the wild taxa C. eximium and C. cardenasii and the domesticate C. pubescens most often show hybrid pollen viability greater than 55%
---------------
The wild form of Capsicum baccatum exhibits a high crossability index with domesticated C. baccatum var. pendulum with the progeny typically exhibiting pollen viability in excess of 55 percent
---------------


In addition to the attached matrix, I've been told in private communication that pubescens and cardenasii will cross.
C. frutescens and praetermissum will also cross but the F1 plants will usually have male sterility.

Breeding peppers can be great fun :)
« Last Edit: September 18, 2013, 08:29:14 PM by Auxin »
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caso

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Re: Breeding interspecific hybrids - Capsicum spp.
« Reply #3 on: December 23, 2015, 09:24:13 AM »

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