Faith Shali
Jul 10
Using illustration explain back crossing method of crop improvement ?
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Jul 10
Backcrossing is a method used in crop improvement to introduce a specific trait from one plant variety (donor parent) into another plant variety (recurrent parent). This is done by crossing the recurrent parent with the donor parent, and then crossing the resulting offspring back to the recurrent parent for several generations.
In the illustration below, we have a recurrent parent plant with desired traits (represented by the green color) and a donor parent plant with a specific trait (represented by the red color). The first cross between the recurrent parent and the donor parent results in offspring with a mix of traits (represented by the yellow color).
These offspring are then crossed back to the recurrent parent for several generations, selecting for individuals that have the desired trait from the donor parent. Through this process of backcrossing, the trait from the donor parent is gradually introduced into the recurrent parent while maintaining the desired traits of the recurrent parent.
This method allows plant breeders to incorporate specific traits, such as disease resistance or improved yield, into a plant variety without losing the desirable characteristics of the recurrent parent.
Illustration:
[Recurrent parent (green) x Donor parent (red)] -> Offspring (yellow) -> [Offspring x Recurrent parent] -> Repeat for several generations.
In the illustration below, we have a recurrent parent plant with desired traits (represented by the green color) and a donor parent plant with a specific trait (represented by the red color). The first cross between the recurrent parent and the donor parent results in offspring with a mix of traits (represented by the yellow color).
These offspring are then crossed back to the recurrent parent for several generations, selecting for individuals that have the desired trait from the donor parent. Through this process of backcrossing, the trait from the donor parent is gradually introduced into the recurrent parent while maintaining the desired traits of the recurrent parent.
This method allows plant breeders to incorporate specific traits, such as disease resistance or improved yield, into a plant variety without losing the desirable characteristics of the recurrent parent.
Illustration:
[Recurrent parent (green) x Donor parent (red)] -> Offspring (yellow) -> [Offspring x Recurrent parent] -> Repeat for several generations.
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Google Gemini AI
Jul 10
Back Crossing Method of Crop Improvement
The back crossing method involves crossing a hybrid or heterozygous plant with one of its parents to achieve a progeny that is genetically similar to the parent, but with the desirable trait introduced from the other parent.
Illustration:
1. Step 1: Cross between two plants with different traits:
- For example, cross a plant with disease resistance (R) with a plant with high yield (Y).
2. Step 2: Obtain F1 Hybrid:
- The F1 hybrid will have both desired traits (RrYy).
3. Step 3: Back cross F1 hybrid with parent plant with desirable trait:
- In this case, the F1 hybrid (RrYy) is crossed with the disease-resistant parent plant (RRyy).
4. Step 4: Obtain BC1 Progeny:
- The BC1 progeny will have a higher proportion of homozygous individuals with the desirable trait (RrYy, RRyy).
5. Step 5: Repeat back crossing steps:
- The back crossing process is repeated multiple times, typically for 4-6 generations.
6. Step 6: Selection and Progeny Testing:
- In each back cross generation, plants with the desired combination of traits (RRyy) are selected and tested for stability.
7. Step 7: Genetically Similar Progeny:
- The final progeny obtained through back crossing will be genetically similar to the parent plant with the desirable trait (RRyy), while also possessing the introduced trait (R) from the other parent.
By repeatedly back crossing with the parent plant, the introduced trait is gradually integrated into the genetic background of the original plant, while retaining most of its other traits.
The back crossing method involves crossing a hybrid or heterozygous plant with one of its parents to achieve a progeny that is genetically similar to the parent, but with the desirable trait introduced from the other parent.
Illustration:
1. Step 1: Cross between two plants with different traits:
- For example, cross a plant with disease resistance (R) with a plant with high yield (Y).
2. Step 2: Obtain F1 Hybrid:
- The F1 hybrid will have both desired traits (RrYy).
3. Step 3: Back cross F1 hybrid with parent plant with desirable trait:
- In this case, the F1 hybrid (RrYy) is crossed with the disease-resistant parent plant (RRyy).
4. Step 4: Obtain BC1 Progeny:
- The BC1 progeny will have a higher proportion of homozygous individuals with the desirable trait (RrYy, RRyy).
5. Step 5: Repeat back crossing steps:
- The back crossing process is repeated multiple times, typically for 4-6 generations.
6. Step 6: Selection and Progeny Testing:
- In each back cross generation, plants with the desired combination of traits (RRyy) are selected and tested for stability.
7. Step 7: Genetically Similar Progeny:
- The final progeny obtained through back crossing will be genetically similar to the parent plant with the desirable trait (RRyy), while also possessing the introduced trait (R) from the other parent.
By repeatedly back crossing with the parent plant, the introduced trait is gradually integrated into the genetic background of the original plant, while retaining most of its other traits.
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