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

• Published in: The New phytologist Vol. 168; no. 2; pp. 455 - 464
• Main Authors: Talukder, Z.I, McDonald, A.J.S, Price, A.H
• Format: Journal Article
• Language: English
• Published: England Blackwell Science 01.11.2005
• Subjects: blast disease; Blasts; Chromosome Mapping; disease resistance; disease severity; Genes, Plant; Genetic loci; genetics; grain crops; Lesions; Magnaporthe; Magnaporthe - pathogenicity; Magnaporthe grisea; metabolism; microbiology; Nitrogen; Nitrogen - metabolism; Oryza; Oryza - genetics; Oryza - metabolism; Oryza - microbiology; Oryza sativa; pathogenicity; Phenotype; Phenotypic traits; Plant Diseases; Plant Diseases - genetics; Plant Diseases - microbiology; plant genetics; plant nutrition; plant pathogenic fungi; Plants; Quantitative Trait Loci; Quantitative traits; Rice
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/j.1469-8137.2005.01507.x

• 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 x 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 x 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 x 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.