Question

One of the most important considerations during the maintenance and production of Breeder's seed in an open-pollinated variety (OPV) is the -

• A. Number of plants/ears to be used to represent the OPV
• B. Number of fertile plants per plot
• C. Number of seedless plants per plot
• D. Number of weed plants per plot

Hint:

To preserve the genetic structure of an open-pollinated variety across generations, you must maintain a large effective population size ($N_e$). Selecting too few plants/ears reduces genetic diversity and leads to rapid inbreeding.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Breeder's seed is the primary source of genetically pure seed from which subsequent classes of certified seed are multiplied.
Open-pollinated varieties (OPVs) are genetically heterogeneous and heterozygous populations because of continuous cross-pollination.
Therefore, maintaining the exact genetic identity and broad genetic base of an OPV during seed multiplication requires avoiding genetic drift and narrowing of the gene pool.

Step 2: Detailed Explanation:
Unlike self-pollinated crop varieties (which can be maintained through single-plant selections), an open-pollinated variety is defined as a diverse population.
If only a few plants or ears are selected during Breeder's seed production, it leads to a severe genetic bottleneck and inbreeding depression.
This results in genetic drift, shifting the original characteristics of the variety.
To prevent this, breeders must harvest a large, representative number of plants or ears (typically 500 to 1000 plants depending on the crop) to adequately represent the complete genetic variability of the original OPV.
These harvested ears are eventually bulked together to maintain the broad genetic base of the population.
Therefore, the number of plants/ears used to represent the OPV is the most critical quality control consideration.

Step 3: Final Answer:
The most important consideration is the number of plants/ears to be used to represent the OPV.