Question

Describe outbreeding devices which encourage cross pollination.

Hint:

Outbreeding devices reduce inbreeding depression, ensuring healthier offspring in plants.

Answer 1

Outbreeding devices promote cross-pollination to enhance genetic diversity: 1. Self-incompatibility: Pollen from the same plant fails to fertilize ovules (e.g., gametophytic or sporophytic systems in Brassica). 2. Dichogamy: Anthers and stigma mature at different times; protandry (anthers first, e.g., sunflower) or protogyny (stigma first, e.g., custard apple). 3. Herkogamy: Physical barriers prevent self-pollination (e.g., stigma above anthers in Hibiscus). 4. Heterostyly: Different flower morphs with varying style/anther lengths (e.g., pin and thrum flowers in Primula). 5. Pollen prepotency: Foreign pollen grows faster on the stigma than self-pollen (e.g., apple).