RFLP Mapping of Genes Conferring Complete and Partial Resistance to Blast in a Durably Resistant Rice Cultivar

• Published in: Genetics (Austin) Vol. 136; no. 4; pp. 1421 - 1434
• Main Authors: Wang, G. L, Mackill, D. J, Bonman, J. M, McCouch, S. R, Champoux, M. C, Nelson, R. J
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Genetics Soc America 01.04.1994; Genetics Society of America
• Subjects: Biological and medical sciences; Chromosome Mapping; Classical genetics, quantitative genetics, hybrids; Fundamental and applied biological sciences. Psychology; Genetic Linkage; Genetics; Genetics of eukaryotes. Biological and molecular evolution; Investigations; Oryza - genetics; Oryza sativa; Plant Diseases; Polymorphism, Restriction Fragment Length; Pteridophyta, spermatophyta; Pyricularia oryzae; Recombination, Genetic; Rice; Vegetals; Genetic mapping; Pyricularia grisea; Monocotyledones; Plant pathogen; Quantitative character; Chromosome 4; Cereal crop; Fungi; Resistance; Oryza sativa; Gene; Gramineae; Angiospermae; Chromosome 11; Spermatophyta; Fungi Imperfecti; Thallophyta
• ISSN: 0016-6731; 1943-2631; 1943-2631
• DOI: 10.1093/genetics/136.4.1421

Moroberekan, a japonica rice cultivar with durable resistance to blast disease in Asia, was crossed to the highly susceptible indica cultivar, CO39, and 281 F7 recombinant inbred (RI) lines were produced by single seed descent. The population was evaluated for blast resistance in the greenhouse and the field, and was analyzed with 127 restriction fragment length polymorphism (RFLP) markers. Two dominant loci associated with qualitative resistance to five isolates of the fungus were tentatively named Pi-5(t) and Pi-7(t). They were mapped on chromosomes 4 and 11, respectively. To identify quantitative trait loci (QTLs) affecting partial resistance, RI lines were inoculated with isolate PO6-6 of Pyricularia oryzae in polycyclic tests. Ten chromosomal segments were found to be associated with effects on lesion number (P < 0.0001 and LOD > 6.0). Three of the markers associated with QTLs for partial resistance had been reported to be linked to complete blast resistance in previous studies. QTLs identified in greenhouse tests were good predictors of blast resistance at two field sites. This study illustrates the usefulness of RI lines for mapping a complex trait such as blast resistance and suggests that durable resistance in the traditional variety, Moroberekan, involves a complex of genes associated with both partial and complete resistance.