Question

The variety of soybean which is being used as a susceptible check for YMV screening is

• A. JS 335
• B. PK 416
• C. SL 295
• D. PK 564

Hint:

In Indian soybean research, JS 335 is widely recognized as the classic susceptible check for YMV, while newer JS and NRC lines are tested against it.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
In plant breeding and pathology, screening germplasm for disease resistance requires the use of standard "checks."
A susceptible check is a variety known to be highly vulnerable to the pathogen, serving as a baseline to ensure the disease pressure is adequate during trials.

Step 2: Detailed Explanation:
Yellow Mosaic Virus (YMV) is a highly destructive viral disease in soybean, transmitted by the whitefly vector (Bemisia tabaci).
The soybean cultivar JS 335 (Jawahar Soybean 335) was once a highly dominant and popular variety in India due to its high yield and adaptability.
However, JS 335 is highly susceptible to YMV under natural and artificial epiphytotic conditions.
Because of its consistent, high susceptibility to the virus, breeders and plant pathologists systematically use JS 335 as the standard susceptible check in screening nurseries to evaluate newly developed lines for YMV resistance.
If JS 335 shows severe yellowing symptoms during the trial, it confirms that the viral disease pressure and vector activity are optimal for evaluating other test varieties.

Step 3: Final Answer:
Therefore, JS 335 is used as the susceptible check for YMV screening.