Question

Orobanche is a problem weed in

• A. Wheat
• B. Tomato
• C. Cotton
• D. Sugarcane

Hint:

Remember the host associations of parasitic weeds:
- Striga (witchweed) \(\rightarrow\) Parasitizes C\( _4 \) cereals (sorghum, maize, sugarcane).
- Orobanche (broomrape) \(\rightarrow\) Parasitizes Solanaceous crops (tomato, tobacco) and mustard.
- Cuscuta (dodder) \(\rightarrow\) Stem parasite of alfalfa and lucerne.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Parasitic weeds are specialized plants that attach themselves to the roots or stems of host plants to extract water, nutrients, and carbohydrates, causing severe yield losses.

Step 2: Detailed Explanation:
Let us analyze the characteristics of Orobanche:
- Orobanche (commonly known as broomrape) is a holoparasitic root weed that lacks chlorophyll and cannot perform photosynthesis.
- Its seeds germinate in response to chemical signals (strigolactones) released by the roots of host plants.
- Once germinated, the parasite develops an organ called a haustorium that penetrates the host root tissue, connecting to the vascular system (xylem and phloem) to extract nutrients.
- Orobanche species primarily target plants in the Solanaceae family (such as tomato (B), tobacco, potato, and brinjal) and the Brassicaceae family (mustard).
- It is not a major parasite of monocots like wheat or sugarcane, nor of malvaceous crops like cotton.
Therefore, Orobanche is a major problem weed in tomato cultivation.

Step 3: Final Answer:
The correct option is (B).