Reference "Mapping QTLs for field resistance to the rice blast pathogen and evaluating their individual and combined utility in improved varieties"

Reference ID

7751

Title

Mapping QTLs for field resistance to the rice blast pathogen and evaluating their individual and combined utility in improved varieties

Source

Theoretical and applied genetics, 2002, vol. 105, pp. 313-324

Authors (6)

Tabien-E	Li-Z
Paterson-H	Marchetti-A
Stansel-W	Pinson-M

Abstract

Lines from a Lemont x Teqing recombinant inbred population were evaluated for
dilatory resistance to rice blast disease using: (1) the Standard Evaluation
System (SES) for rating leaf blast, (2) the percentage diseased leaf area
(%DLA), and (3) the area under a disease progress curve (AUDPC). RFLP mapping
using 175 well-distributed loci revealed nine QTLs, one each on chromosomes 1,
2, 3, 4, 6, 7 and 9, with two loci on chromosome 12. All nine putative QTLs were
associated with AUDPC, six with both a %DLA and a SES rating. Teqing contributed
the resistance allele for all these loci except for the one located on
chromosome 4. Individual QTLs accounted for 5-32% of the observed phenotypic
variation, and combined QTL models accounted for 43-53%. Three QTLs were located
near three of the four major resistance genes previously identified in this
population. The resistances of both Lemont and Teqing were attributable to a
combination of both major genes capable of inducing hypersensitive reactions and
minor genes causing less-distinctive phenotypic differences. Interactions were
noted between QTLs and major genes. Our findings are in support of the strategy
of pyramiding major genes and QTLs in carefully selected combinations to develop
improved varieties with resistance to the blast fungus that is both broad in
spectrum and durable.