Indian Society of Genetics & Plant Breeding

Molecular analysis and phenotypic validation of blast resistance genes Pita and Pita2 in landraces of rice (Oryza sativa L.)

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Rice (Oryza sativa L.) crop confronts several major and
minor diseases of which blast disease caused by
Magnaporthe oryzae is a serious constraint causing
moderate to huge economic losses world over. Exploitation
of genetic resistance in cultivars is a preferred management
strategy. Though the number of genes for resistance to
blast have been cloned and mapped, however, as because
of their variable efficacy and donor traits there remains a
scope for discovery of alleles and hence fresh donors
among local collections and landraces. Present
investigation was undertaken with the objective towards
screening of 100 germplasm accessions for Pita-Pita2, the
two tightly linked dominant genes governing major gene
blast resistance. An attempt was made to identify the
genotypes carrying individually or in combination the genes
Pita and Pita2 with the help of molecular markers and
differential screening using diagnostic isolates. Based on
PCR assay using two gene based markers, 27 accessions
were found carrying resistance specific alleles. Differential
screening results coupled with marker information helped
to classify the genotypes in five categories. Out of the
marker positive accessions, 11 were supposed to possess
Pita and in 9 other genotypes the presence of Pita and (or)
Pita2 was validated. Besides this, the validation of markers
linked to Pita-Pita2 locus was performed across varieties
and landraces grown in India to assess their use and
relevance in MAS. The identified gene sources may serve as
new donors and a subject for further genetic and genomic

Keywords: Rice blast, resistance, Pita, Pita2, markers, landraces


Year: 2013
Volume: 73
Issue: 2
Article DOI: 10.5958/j.0975-6906.73.2.020
Print ISSN: 0019-5200
Online ISSN: 0975-6906


U. D. Singh info_circle
R. Rathour info_circle
V. Tonapi info_circle
T.R. Sharma info_circle
M. Nagarajan info_circle
K. V. Prabhu and A. K. Singh info_circle

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