Self Study Quiz - Backcross Breeding (Advanced Level) Go Back
1. What is the purpose of backcross breeding?
To create lower-yielding lines.
To move the transgene to a higher yielding (elite line).
Backcross breeding is used only when a plant breeder wants to stack multiple desired genes into one elite line.
none of the above

2. Which phrase is not true about backcross breeding?
It is a practice that has been used by plant breeders for decades.
Backcross breeding is repeated until the offspring has 99+% elite genes and the transgene.
Backcross breeding is a new technique developed for genetically engineered plants.
Backcross breeding is often used to reduce yield drag.

3. How do breeders identify plants that express the desired traits?
Through observation
They use an ELISA test
They use a PCR test
all of the above

4. What is yield drag?
The difference in yield potential between a transgenic line and the newest elite lines.
The negative effect on yield potential associated with crop plants that have a specific gene, trait, or when there is a disruption of a gene important for yield.
The lag period" in which the plant breeder has not imposed selection for yield.
Reduction in the yield amount found only in genetically engineered plants?

5. Which phrase best describes gene stacking?
Screening for the presence of negative mutations that occurred during the transformation process.
Stacking genes end-on-end to increase yield.
Combining more than one desired trait into one line.
Combining gene libraries for multiple screens of desired gene traits.

6. What are the way(s) genes can be stacked?
Plant breeders stack genes by making crosses between parents that each have a desired trait and then identifying offspring that have both of these desired traits.
By transferring two or more genes into the cell nucleus during transformation.
By either of the above methods
Neither of the above methods

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