Loci controlling partial resistance to rice blast do not show marked QTL × environment interaction when plant nitrogen status alters disease severity

• Published in: The New phytologist Vol. 168; no. 2; pp. 455 - 464
• Main Authors: Talukder, Zahirul I., McDonald, A James S., Price, Adam H.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.11.2005; Blackwell
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; blast disease; disease severity; disease susceptibility; Fundamental and applied biological sciences. Psychology; Genetics and breeding of economic plants; Magnaporthe grisea; Magnaporthe grisea (blast); nitrogen; nitrogen (N); nitrogen content; Oryza sativa; Oryza sativa (rice); partial resistance; Pest resistance; plant nitrogen content; Plant pathogens; QTL × E (environment); quantitative trait loci; quantitative trait loci (QTL); quantitative traits; rice; R‐genes; Varietal selection. Specialized plant breeding, plant breeding aims; Agronomic character; Monocotyledones; nitrogen (N); Plant pathogen; Magnaporthe grisea (blast); QTL x E (environment); Cereal crop; Fungi; Oryza sativa; Gramineae; Angiospermae; Ascomycetes; Pretreatment; Thallophyta; R-genes; Oryza sativa (rice); Chromosome; Nitrogen; Fungus resistance; Quantitative trait loci; quantitative trait loci (QTL); Magnaporthe grisea; Sensitivity resistance; Genotype environment interaction; partial resistance; Spermatophyta
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/j.1469-8137.2005.01507.x

Summary •  Plant disease susceptibility is often increased by nitrogen (N) application. Therefore, it is important to know if resistance loci are effective in different plant N environments. •  One‐hundred lines of the Bala × Azucena rice (Oryza sativa) mapping population were grown in two N treatments and tested for partial resistance to blast (Magnaporthe grisea) isolate CD100. Disease severity (DS), the number and size of lesions and plant N and C concentrations were measured and the results subject to quantitative trait loci (QTL) and QTL × environment analysis. •  There was a 66% higher plant N concentration in the high N treatment and DS increased significantly, mostly as a result of increased numbers of lesions. Nine regions contained QTL for disease traits but only one showed evidence of statistically significant QTL × treatment interaction. This was a large effect quantitative trait locus at marker R1933 on chromosome 12 which was less effective at high N. •  Apparently, blast disease is increased by higher plant N, but the efficacy of partial resistance genes is not greatly affected by N application.