Cytoplasmic Male Sterility
Summary
TLDRThe video script delves into the concept of cytoplasmic male sterility (CMS), a vital technique in hybridization programs. CMS is controlled by plasmogenes in the cell's mitochondria or plastids, preventing self-pollination and encouraging cross-pollination, thereby eliminating the need for manual emasculation. It has been observed in over 150 plant species, including beans, beets, carrots, and wheat. CMS involves two types of cytoplasm: normal and sterile, with the latter producing male sterile plants. Inheritance of CMS is non-Mendelian, as it is passed down through the female parent's cytoplasm. It is applicable in crops where vegetative parts are valuable but not in seed-focused crops due to the inheritance of sterility. CMS can be introduced into a plant line through hybridization with a male sterile line carrying the CMS factors. The process involves backcrossing and maintaining the trait by crossing a male sterile line with an isogenic male fertility line. The resulting hybrid is always male sterile, ensuring the CMS trait's continuation.
Takeaways
- đ± Cytoplasmic male sterility (CMS) is a genetic trait found in the mitochondria or chloroplasts of plant cells that prevents self-pollination and encourages cross-pollination.
- đ CMS is a crucial technique in hybridization programs, eliminating the need for emasculation, a process where the male parts of a flower are removed to prevent self-fertilization.
- đŸ Over 150 plant species, including common crops like beans, beets, carrots, onions, and wheat, have been reported to exhibit CMS.
- đŹ There are two types of cytoplasm in CMS: normal cytoplasm, which produces male-fertile plants, and sterile cytoplasm, which results in male-sterile plants.
- đ©âđ§âđŠ Male sterility is inherited maternally because the female gamete contributes cytoplasm to the zygote, leading to a non-Mendelian inheritance pattern.
- đ« CMS cannot be used in crops where the seed is the valuable component, as the hybrid offspring would inherit the male sterile cytoplasm.
- đż CMS can be utilized in crops where the vegetative parts have economic value, such as in certain types of plants where the leaves or stems are harvested.
- đ The process of transferring CMS involves crossing a line with male-sterile cytoplasm and non-restorative genes with a line that has male-fertile cytoplasm and non-restorative genes.
- đ The F1 generation resulting from the initial cross is then backcrossed for several generations to stabilize the desired traits.
- đ Isogenic lines differing only in male sterility cytoplasm are used to maintain CMS, where the male-sterile line carries the factors for CMS and the male-fertile line provides functional pollen.
- đ« The final hybrid is produced by crossing a male-sterile line with a male-fertile line, ensuring that the hybrid remains male sterile.
Q & A
What is cytoplasmic male sterility?
-Cytoplasmic male sterility is a genetic condition governed by plasmogenes located in mitochondria or chloroplasts of the cell, which prevents self-pollination and promotes cross-pollination in plants.
Why is cytoplasmic male sterility important in hybridization programs?
-It is important because it eliminates the need for emasculation, a process where the male reproductive parts of a plant are removed to prevent self-pollination, thus facilitating controlled cross-pollination.
How many plant species have been reported to exhibit cytoplasmic male sterility?
-Cytoplasmic male sterility has been reported in over 150 plant species, including common crops like beans, beets, carrots, and wheat.
What are the two types of cytoplasm associated with cytoplasmic male sterility?
-There are two types of cytoplasm: normal cytoplasm, which produces male fertile plants, and sterile cytoplasm, which produces male sterile plants.
How is male sterility inherited in plants with cytoplasmic male sterility?
-Male sterility is inherited through the female parent because the female gamete contributes cytoplasm to the zygote, which contains the cytoplasmic factors responsible for male sterility.
Why doesn't the inheritance pattern of cytoplasmic male sterility follow Mendelian inheritance rules?
-The inheritance pattern does not follow Mendelian rules because it is based on the transmission of genetic traits from the female parent only, rather than both parents as in classical Mendelian inheritance.
In what types of crops can cytoplasmic male sterility be utilized?
-Cytoplasmic male sterility can be used in crops where the vegetative parts have economic value, but it cannot be used in crops where the seed is the valuable component, as the hybrid offspring would inherit male sterility.
How is cytoplasmic male sterility transferred to the female parent in a hybridization program?
-It is transferred by crossing a line with male sterilized cytoplasm and non-restora genes with a male fertile line with normal cytoplasm and non-restora genes, followed by backcrossing for several generations.
What are isagenic lines in the context of maintaining cytoplasmic male sterility?
-Isagenic lines are genetically identical lines that differ only in male sterility. They are used to maintain cytoplasmic male sterility by crossing a male sterile A line with an isagenic male fertile B line.
How is a hybrid produced using cytoplasmic male sterility?
-A hybrid is produced by crossing a male sterile A line with a male fertile C-line. The resulting hybrid is always male sterile due to the presence of the male sterile cytoplasm.
Outlines
đ± Cytoplasmic Male Sterility in Plant Hybridization
This paragraph delves into the concept of cytoplasmic male sterility (CMS), a vital technique in plant hybridization programs. CMS is controlled by plasmogenes in the mitochondria or chloroplasts, preventing self-pollination and encouraging cross-pollination. The paragraph explains that CMS is not governed by classical Mendelian inheritance but follows a non-Mendelian or cytoplasmic inheritance pattern, as it is inherited maternally through the female gamete. The script also highlights that CMS has been identified in over 150 plant species, including common crops like beans, beets, carrots, and wheat. The paragraph discusses the practical application of CMS in crops where vegetative parts are economically valuable, but notes its limitation in seed-based crops due to the inheritance of male sterility by the offspring. It outlines the process of transferring CMS through hybridization by crossing a line with male sterilized cytoplasm with one having male fertile cytoplasm and non-restora genes. The resulting F1 plants are male sterile, and the process of maintaining CMS through backcrossing and using isogenic lines is described.
Mindmap
Keywords
đĄCytoplasmic Male Sterility (CMS)
đĄPlasmogenes
đĄHybridization Program
đĄSelf-Pollination
đĄCross-Pollination
đĄNormal Cytoplasm
đĄSterile Cytoplasm
đĄNon-Mendelian Inheritance
đĄIsagenic Lines
đĄMale Sterile A-Line
đĄMale Fertile C-Line
Highlights
Cytoplasmic male sterility is an essential technique in hybridization programs.
It is governed by plasmogenes located in mitochondria or pleuroplast.
Prevents self-pollination and promotes cross-pollination.
Eliminates the need for emasculation in hybridization.
Reported in over 150 plant species including common crops.
There are two types of cytoplasm: normal and sterile.
Normal cytoplasm produces male fertile plants.
Sterile cytoplasm produces male sterile plants.
Inheritance is through the female parent due to cytoplasmic contribution.
Does not follow classical Mendelian inheritance rules.
Inheritance is described as non-Mendelian or cytoplasmic.
Useful in crops where vegetative parts have economic value.
Not suitable for crops where seed is a valuable component.
Transferred to female parent by crossing with male sterile cytoplasm.
F1 generation is backcrossed for six to seven generations.
A and B lines are isagenic, differing only in male sterility.
Maintained by crossing male sterile A line with male fertility B line.
Hybrid is produced by crossing male sterile A line with male fertile C line.
Hybrid offspring are always male sterile.
Transcripts
this video offers an in-depth
examination of cytoplasmic male
sterility an essential technique
employed in the hybridization program
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cytoplasmic male sterility is governed
by plasmogenes located in mitochondria
or pleuroplast of the cell
cytoplasmic mail sterility prevents
self-pollination and promotes
cross-pollination
hence it is employed in hybridization
program to eliminate the need for
emasculation
cytoplasmic maze sterility has been
reported in over 150 plant species
including common Bean beet carrot match
onion chili radish petunia rapeseed rice
Rye sorghum sunflower and wheat
in cytoplasmic male sterility there are
two types of cytoplasm normal cytoplasm
and sterile cytoplasm
plants with normal cytoplasm produce
male fertile plants wild plants with
sterile cytoplasm produce male steroid
plants
male sterility is inherited by female
parent because female gamete contributes
cytoplasm to the zygote
The Inheritance pattern does not follow
the classical mendeline inheritance
rules that are based on the transmission
of genetic traits from both parents
instead the inheritance of cytoplasmic
male stability is often described as
non-mendelian or cytoplasmic inheritance
cytoplasmic male sterility can be used
in crops where the vegetative Parts have
economic value
however it cannot be used in crops where
the seed is a valuable component as the
resulting hybrid offspring would inherit
male stability
cytoplasmic male sterility can be
transferred to female parent in
hybridization program by crossing a line
with male sterized cytoplasm and
non-restora Gene would be lying with
male fertile cytoplasm and non-restora
Gene
the resulting F1 is back crossed would
be lying for six to seven generations
the A and B lines are isagenic lines
differing only in male sterility
cytoplasmic male sterility is maintained
by crossing a male sterile a line with
an isagenic male fertility line
the male sterile a line carries the
cytoplasmic factors responsible for male
stability while the isagenic male
fertile b line serves as the pollinator
to provide the functional pollen for
fertilization
the F1 plants will be males steroid due
to the presence of the male sterile
cytoplasm
hybrid is produced by Crossing male
steri a line with male fertile c-line
the hybrid is always male sterile
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