Mineral evaluation and Quantitative Trait Loci mapping in a soybean (Glycine max (L.) Merr.) population developed for iron deficiency chlorosis resistance
Silvia R. Cianzio
The identification of the causal gene(s) of disease resistance is paramount in plant breeding. Nutrient analysis in plant tissues can lead to the identification of these gene(s). The objectives of this research were 1) to map quantitative trait loci (QTL) for seed and leaf iron and zinc concentration in the soybean population Anoka x A7, 2) to determine if QTL for iron and zinc accumulation co-localized to the same regions of the genome, 3) to determine if any of newly identified QTL for Fe and/or Zn concentration correlate with QTL previously identified for Fe efficiency, 4) to determine the amount of variation of total phosphorus in a population developed for iron deficiency chlorosis resistance, and 5) to map total phosphorus as a QTL. Iron, zinc, and total phosphorus concentration was determined in 92 F2:4 lines from the Anoka x A7 population grown on non-calcareous soil grown in 2008 and 2009. Dry ashing was the method used to determine iron and zinc, and total phosphorus was determined through an overnight digestion. Nutrients in each set of samples were quantified using inductively coupled plasma-optical emission spectrometry (ICP-OES). The genetic map was integrated with the map of Lin et al. (1997) which consisted of a total of 150 markers and used to locate QTL.
For the iron and zinc study, one significant QTL for iron concentration in soybean seed was mapped on chromosome 20 in the combined data. One marker in this QTL interval, pa_515-1, previously mapped an Fe efficiency QTL. This result presented evidence of a genetic link between Fe efficiency and iron concentration in soybean.
In the total phosphorus study, one significant QTL was mapped on chromosome 12 for phosphorus concentration in the combined data. Candidate genes in this marker interval, S12_0711-S12_1103, are involved in the P storage and homeostasis pathways and mediate the transport of phosphate. The results of this study indicated that total phosphorus uptake and transport could be modified.