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Australian agricultural biologists are currently researching weeping rice grass (Microleana stipoides), a deep-rooted native relative of rice - VCE - SSCE Biology - Question 6 - 2007 - Paper 1
Question 6
Australian agricultural biologists are currently researching weeping rice grass (Microleana stipoides), a deep-rooted native relative of rice. Their aim is to produc... show full transcript
Worked Solution & Example Answer:Australian agricultural biologists are currently researching weeping rice grass (Microleana stipoides), a deep-rooted native relative of rice - VCE - SSCE Biology - Question 6 - 2007 - Paper 1
Step 1
a. The seed size trait is most likely to be polygenic. What is a polygenic trait?
Answer
A polygenic trait is one that is influenced by multiple genes, which can result in a range of phenotypes rather than a simple either/or outcome. Traits such as height, skin color, and seed size are often polygenic, as they involve interactions between several genes.
Step 2
b. What might be the advantage of breeding this species for larger seed size?
Answer
Breeding weeping rice grass for larger seed size could lead to several advantages, such as increased yield per plant, enhanced drought resistance due to a larger nutrient reserve, and improved marketability of the crop. Larger seeds may also provide better establishment and survival rates in various environmental conditions.
Step 3
c. If you were a farmer involved in a systematic breeding program, outline the steps you should take to develop a variety of weeping rice grass with large seeds.
Answer
To develop a variety of weeping rice grass with large seeds, follow these steps:
- Selection of Parent Plants: Identify and select the largest seeds from the existing weeping rice grass populations.
- Cross-Pollination: Perform controlled pollination between the selected parent plants to combine desirable traits.
- Seed Harvesting: Collect and plant the seeds that result from the cross-pollination.
- Phenotypic Assessment: Evaluate the offspring for seed size and other desirable traits once they mature.
- Further Selection: Select the offspring with the largest seeds for further breeding rounds.
- Repetition of Breeding Process: Repeat this process over multiple generations to stabilize the trait for larger seed size.
- Field Trials: Conduct trials under various environmental conditions to assess the performance and adaptability of the new variety.
- Propagation and Distribution: Once a stable population showing large seed size is achieved, propagate the seeds and distribute them for commercial use.