AbstractGene pyramiding is considered one of the most effective strategies for
achieving durable resistance against blast disease (Magnaporthe oryzae
B. Couch) in rice (Oryza sativa L.), although few studies have
evaluated the combining effect of the resistance genes. We report the
development of pyramided lines with two major blast resistance genes,
Pish and Pib, and the evaluation of the combining effect of them. The
two genes pyramided lines were selected from the progenies of a cross
between one near isogenic line (NIL), which harbours Pish, and
another NIL, which harbours Pib, in the genetic background of blast
susceptible variety, CO 39. The presence of the resistance genes was
confirmed by DNA markers linked to them. To obtain DNA markers
for Pish, we genetically mapped the Pish locus. We confirmed the
additive effect of Pish and Pib in the pyramided lines by their reaction
patterns to blast isolates, suggesting the potential availabilities of the
combinations of these genes. In addition, we provide DNA markers
linked to Pish for marker aided selection in rice blast resistance
breeding.