Q.53 The alternate host for Puccinia graminis is
1. Delonix regia
2. Thalictrum falvum
3. Muehlenbergia hugeli
4. Berberis vulgaris
Alternate Host of Puccinia graminis: Berberis vulgaris Revealed
Puccinia graminis, the causal agent of stem rust in wheat and other cereals, requires an alternate host to complete its heteroecious life cycle. Among the given options, Berberis vulgaris stands out as the correct alternate host.
Correct Answer
4. Berberis vulgaris
This shrub serves as the secondary (aecial) host where Puccinia graminis undergoes sexual reproduction, producing pycnia and aecia stages essential for genetic recombination and overwintering teliospores from the primary grass host.
Option Explanations
| Option | Plant Name | Role in Puccinia graminis Cycle | Explanation |
|---|---|---|---|
| 1 | Delonix regia (Flame Tree) | Not an alternate host | Tropical flowering tree from Fabaceae; unrelated to rust fungi cycles of cereals. No documented role in Puccinia life history. |
| 2 | Thalictrum flavum (Yellow Meadow-Rue) | Not an alternate host | Herbaceous perennial in Ranunculaceae; hosts other rusts but not Puccinia graminis. Lacks evidence as barberry substitute. |
| 3 | Muehlenbergia hugeli (a grass) | Primary host candidate | Gramineous grass potentially serving as uredinial/telial host like wheat, not alternate (aecial) host. |
| 4 | Berberis vulgaris (Common Barberry) | Correct alternate host | Classic secondary host enabling pycnial and aecial stages; critical for pathogen recombination. Confirmed in studies across regions. |
Life Cycle Insight
Puccinia graminis infects cereals (primary host) with urediniospores for rapid spread, then teliospores germinate to basidiospores infecting Berberis vulgaris leaves, forming aecia whose spores reinfect cereals—linking options to rust epidemiology.
