How can pollen grains of wheat and rice which tend to lose viability within 30 minutes of their release be made available months later for bredding programmes ?

Explanation

### Step-by-Step Solution:

1. **Understanding Pollen Viability**:
- Pollen grains of wheat (Triticum aestivum) and rice (Oryza sativa) lose their viability within 30 minutes after being released into the environment. This means they cannot fertilize the ovules after this short period.

**Hint**: Consider the lifespan of pollen grains and the factors that affect their viability.

2. **Characteristics of Pollen Grains**:
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