Theoretical and Applied Genetics

, Volume 103, Issue 2, pp 185–190

QTL analysis and mapping of pi21, a recessive gene for field resistance to rice blast in Japanese upland rice

  • S. Fukuoka
  • K. Okuno
Original Paper

DOI: 10.1007/s001220100611

Cite this article as:
Fukuoka, S. & Okuno, K. Theor Appl Genet (2001) 103: 185. doi:10.1007/s001220100611

Abstract 

Field resistance is defined as the resistance that allows effective control of a parasite under natural field conditions and is durable when exposed to new races of that parasite. To identify the genes for field resistance to rice blast, quantitative trait loci (QTLs) conferring field resistance to rice blast in Japanese upland rice were detected and mapped using RFLP and SSR markers. QTL analysis was carried out in F4 progeny lines from the cross between Nipponbare (moderately susceptible, lowland) and Owarihatamochi (resistant, upland). Two QTLs were detected on chromosome 4 and one QTL was detected on each of chromosomes 9 and 12. The phenotypic variation explained by each QTL ranged from 7.9 to 45.7% and the four QTLs explained 66.3% of the total phenotypic variation. Backcrossed progeny lines were developed to transfer the QTL with largest effect using the susceptible cultivar Aichiasahi as a recurrent parent. Among 82 F3 lines derived from the backcross, resistance segregated in the expected ratio of resistant 1 : heterozygous 2 : susceptible 1. The average score for blast resistance measured in the field was 4.2 ± 0.67, 7.5 ± 0.51and 8.2 ± 0.66, for resistant, heterozygous and susceptible groups, respectively. The resistance gene, designated pi21, was mapped on chromosome 4 as a single recessive gene between RFLP marker loci G271 and G317 at a distance of 5.0 cM and 8.5 cM, respectively. The relationship to previously reported major genes and QTLs conferring resistance to blasts, and the significance of marker-assisted selection to improve field resistance, are discussed.

Keywords Disease resistance Field resistance Rice (Oryza sativa L.) Rice blast (Pyricularia grisea Sacc.) 

Copyright information

© Springer-Verlag Berlin Heidelberg 2001

Authors and Affiliations

  • S. Fukuoka
    • 1
  • K. Okuno
    • 1
  1. 1.Department of Genetic Resources I, National Institute of Agrobiological Resources, Kannondai 2-1-2, Tsukuba, Ibaraki, 305-8602 Japan e-mail: fukusan@abr.affrc.go.jp, Present address: K. Okuno, Department of Low-Temperature Sciences, Hokkaido National Agricultural Experiment Station, Hitsujigaoka 1,Toyohira, Sapporo, Hokkaido, 062-0045 JapanJP

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