Question

Suicidal germination is a promising option in combating:

• A. Dodder
• B. Striga
• C. Loranthus
• D. Rhizoctonia

Hint:

Obligate root parasitic weeds like Striga and Orobanche are the primary targets of suicidal germination.
Look for the use of synthetic strigolactones or ethylene gas as the chemical triggers in these management scenarios.

Answer 1

The Correct Option is B

Suicidal germination is a specialized chemical and ecological weed management strategy used to control obligate root parasitic weeds.
These parasitic weeds produce millions of tiny seeds that can remain dormant in the soil for decades.
They only germinate when they detect specific chemical signals, known as germination stimulants, released by the roots of nearby host plants.
If these dormant seeds are artificially stimulated to germinate in the absence of a host plant, the newly germinated seedlings cannot survive.
Because they are obligate parasites, they lack the chlorophyll and root systems necessary to sustain independent growth.
Consequently, the seedlings die of starvation within a few days, a process termed "suicidal germination."

Step 2: Detailed Explanation:
The genus Striga (commonly known as witchweed) consists of highly destructive root parasitic weeds that mainly infect cereal crops like sorghum, maize, pearl millet, and sugarcane in semi-arid tropical regions.
The seeds of Striga require host-derived chemical stimulants, predominantly strigolactones, to trigger their germination.
In a suicidal germination control strategy, synthetic analogs of strigolactones, such as GR24, or other natural stimulants like ethylene gas are applied to infested fields before planting the main crop.
This triggers the dormant Striga seeds to germinate prematurely.
Without the presence of a host root to parasitize and establish a haustorial connection for nutrient and water transfer, the emerged seedlings die of starvation.
This strategy significantly depletes the massive seed bank of Striga in the soil, which is otherwise extremely difficult to manage using conventional weeding.
Let us analyze the other options to understand why they are incorrect:
- Cuscuta (Dodder) is an obligate stem parasite that germinates independently without requiring specific root exudates; it finds host plants by sensing volatile chemical cues in the air.
- Loranthus is a partial stem parasite (hemiparasite) that is primarily dispersed by birds onto tree branches and does not undergo a soil-dwelling germination phase.
- Rhizoctonia is a soil-borne fungal pathogen rather than a parasitic weed, meaning its lifecycle and control do not involve seed germination mechanisms.

Step 3: Final Answer:
Therefore, suicidal germination is a highly promising and specific option for combating Striga infestations.