Multienvironment Quantitative Trait Loci Mapping and Consistency across Environments of Resistance Mechanisms to Ferrous Iron Toxicity in Rice uri icon

abstract

  • Lowland rice (Oryza sativa L.) is often affected by iron toxicity, which may lead to yield losses. One important constraint in the study of genetic determinism of plants’ resistance strategies to this stress is the inconsistency of gene expression across different environments. This study aimed to check the consistency of quantitative trait loci (QTLs) across several environments. QTL mapping for traits related to resistance mechanisms had been previously carried out using 164 recombinant inbred lines derived from Azucena and IR64, screened in hydroponics in a phytotron. In the present study, this population was tested under iron-toxic conditions in three additional experimental conditions whose level of control differed widely: hydroponics: from highly controlled conditions (hydroponics), to the field. A total of 44 putative QTLs were identified in the four analyses for morphological, physiological and agronomic traits. From these 44 QTLs, 20 were found in overlapping regions for the same or related traits in different environments, identifying six regions of great interest for the determinism of resistance to iron toxicity. QTL stability across environments was also checked by performing a joint QTL analysis, which confirmed the position of nine QTLs previously found in the same or adjacent regions by at least one analysis. Combining both single and joint analyses helps in separating QTLs induced by a particular environment from constitutive QTLs that are more suitable for marker-assisted selection
  • Lowland rice (Oryza sativa L.) is often affected by iron toxicity, which may lead to yield losses. One important constraint in the study of the inheritance of resistance strategies to this stress is the inconsistency of gene expression across different environments. This study aimed to determine the stability of quantitative trait loci (QTL) across several environments. Quantitative trait loci mapping for traits related to resistance mechanisms had been previously performed using 164 recombinant inbred lines derived from 'Azucena' and 'IR64' screened in hydroponics in a phytotron. In the present study, this population was tested under excessive ferrous iron conditions in three additional environments: in hydroponics in a greenhouse, on washed sand, and in the field. Altogether, 44 putative QTL were identified in the four single QTL analyses for morphological, physiological, and agronomic traits. From these 44 QTL, 20 were found in overlapping regions for the same or related traits in different environments, identifying six genomic regions of great interest for the inheritance of resistance to iron toxicity. Quantitative trait loci Stability across environments was also checked! by performing a joint QTL analysis, which confirmed the position of nine QTL previously found in the same or adjacent regions by at least one single analysis. Combining both single and joint analyses helps in separating QTL specific to a particular environment from generally expressed ones thus is more suitable for marker-assisted selection.

publication date

  • 2012
  • 2012
  • 2012