The Xa21 gene in rice develops resistance to –

Correct option is B

Correct option (b) Bacterial blight disease
· Xa21 provides resistance against Xanthomonas oryzae pv. oryzae.
· Widely used in rice breeding programs.
Other options:
· (a) Rice blast – Caused by fungus Magnaporthe oryzae.
· (c) Sheath blight – Caused by Rhizoctonia solani.
· (d) False smut – Caused by Ustilaginoidea virens.