Question

Ug99 is new race of Puccinia graminis f. sp. tritici
(A). Ug99 was first emerged in Uttar Pradesh
(B). Ug99 was first emerged in Uganda in 1999
(C). Ug99 was first emerged in Uganda in 1998
(D). Subvariants of Ug99 is emerged recently
Choose the correct answer from the options given below:

• A. (A), (B) and (D) only.
• B. (B) and (C) only.
• C. (C) and (D) only.
• D. (B), (C) and (D) only.

Hint:

While named Ug99, this stem rust lineage was first detected in Uganda in 1998. It has since diversified into several subvariants that overcome multiple resistance genes.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Ug99 is a highly virulent lineage of the fungus Puccinia graminis f. sp. tritici, which causes stem rust in wheat.
This strain is a major threat to global food security because it can overcome the widely used stem rust resistance gene Sr31, which had successfully protected wheat crops for decades.

Step 2: Detailed Explanation:
Let us evaluate each of the given statements:
Statement (A) is incorrect: Ug99 did not emerge in Uttar Pradesh, India.
It originated in East Africa and posed a severe threat of spreading to the Middle East and South Asia.
Statement (B) is incorrect: Although the name contains "99" (reflecting the year 1999, when its wide-scale threat was formally recognized and characterized), the strain was first detected and collected in Uganda in 1998.
Therefore, Statement (C) is correct: Ug99 was first identified in Uganda in 1998.
Statement (D) is correct: Since its discovery, the Ug99 lineage has evolved.
Mutations in the pathogen population have led to the emergence of several subvariants or sister lineages within the Ug99 group (such as TTKSK, TTKST, and TTTSK).
These subvariants have acquired virulence against additional rust resistance genes, such as Sr24 and Sr36, making them even more dangerous.
Therefore, only statements (C) and (D) are correct.

Step 3: Final Answer:
Hence, the correct option is (C).