Indian Society of Genetics & Plant Breeding

Development and validation of a functional dCAPS marker for OsAHASrb governing imazethapyr tolerance in rice

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Adoption of direct-seeded rice (DSR) cultivation requires
sustainable weed management strategies for making it
viable. The development of herbicide-tolerant (HT) rice
varieties will help address this gap. Robin, an EMS induced
mutant of Nagina 22 (N22), tolerates the application of
imazethapyr, a broad-spectrum herbicide of the
imidazolinone group. A mutation in the
(acetohydroxyacid synthase) gene offers HT in Robin. The
mutant allele is named
AHASrb. In the present study, we
developed a derived cleaved amplified polymorphic
sequences (dCAPS) marker, AKS-dAHAS, based on the
single nucleotide polymorphism (SNP) in
AHASrb, which
had a G to A mutation at the 1880
th position. This mutation
causes an amino acid substitution at 627
th serine residue
to asparagine (S627N) in the AHAS enzyme. We have
demonstrated that AKS-dAHAS perfectly distinguishes the
wild type allele of Nagina 22 (
AHAS) from the mutant allele,
AHASrb. AKS-dAHAS showed perfect co-segregation with
HT trait in two independent F
2 populations. Unlike the linked
marker, RM6844, the AKS-dAHAS showed no recombinants
with the HT trait, ensuring utmost precision in selection for
imazethapyr tolerance. This marker enables precise transfer
AHASrb into elite rice varieties through marker-assisted
breeding, thereby imparting imazethapyr tolerance making
them suitable for DSR cultivation.

Keywords: dCAPS, OsAHAS, herbicide tolerance, imazethapyr, direct-seeded rice


Year: 2021
Volume: 81
Issue: 3
Article DOI: 10.31742/IJGPB.81.3.2
Print ISSN: 0019-5200
Online ISSN: 0975-6906



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