Despite its name, Kentucky Bluegrass is a widespread turfgrass used for lawns throughout the United States. In some regions, strains have developed desirable disease-resistant properties. However, Kentucky Bluegrass typically develops by apomixis. Plant breeders say this creates both a challenge and an opportunity for engineering novel strains. Why?

Question

A.  In apomixis, new plants develop from underground horizontal stems. This allows for fast propagation of new strains, but all progeny are identical to the parent. 
B.  Plants that develop by apomixis are naturally tolerant of herbicides. As a result, herbicide tolerance genes cannot be used as selectable markers for a transgene, but herbicides can be used to keep the resulting culture pure.
C.  Since the progeny of apomixis are triploid, hybrids have an imbalance of parental genes. However, this may be desirable if a higher proportion of one allele is beneficial.
D.  If a seed develops by apomixis, it will be identical to its parent. Hybridization with another strain requires special techniques. However, once a hybrid strain is developed, apomixis ensures its reliable propagation.

Clarify Question
What is the key concept addressed by the question?
What type of thinking is required?
 
Gather Content
What do you already know about apomixis? What other information is related to the question?

Choose Answer
Given what you now know, what information is most likely to produce the correct answer?

Reflect on Process
Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?    

Answer 1

D.  If a seed develops by apomixis, it will be identical to its parent. Hybridization with another strain requires special techniques. However, once a hybrid strain is developed, apomixis ensures its reliable propagation.

Clarify Question
What is the key concept addressed by the question?
        · This question is asking you to explain why apomixis is both challenging and beneficial in the production of Kentucky Bluegrass..
What type of thinking is required?
        · Analyze level:
            o This is an analyze question because you have to break the challenges and opportunities presented by apomixis into their component pieces to understand how they function.
 
Gather Content
What do you already know about apomixis? What other information is related to the question?
        · Apomixis is the process by which an embryo is produced asexually via the cloning of diploid cells.
        · Embryos produced through apomixis are diploid and are identical to the parent cell.

Choose Answer
Given what you now know, what information is most likely to produce the correct answer?
        · Apomixis is really the formation of an embryo through mitosis; the process itself forms seeds, not extensions of the existing parent.
        · The embryos that result from apomixis are diploid, not triploid, so that answer can be excluded.
        · Embryos formed through apomixis are not pesticide-resistant unless the parent plant is pesticide-resistant.
        · Apomixis involves the creation of a clone of a parent cell, so the offspring are identical to the parent. Since this is asexual reproduction, hybridizing two different strains would need special techniques, but would result in plants that could be propagated.

Reflect on Process
Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?         · Analyze level:
            o Answering this question correctly depended not only on distinguishing between the benefits and challenges of apomixis, but on your ability to analyze the components of apomixis. If you got an incorrect answer, did you remember that components of apomixis include the formation of a diploid embryo, or that the embryo is a clone of the parent? Did you have trouble breaking down the process of apomixis to determine the correct answer?