Crop Biotech Update

Researchers Map Several QTLs for Maize Gray Leaf Spot Resistance

September 3, 2014

Gray leaf spot (GLS) caused by some Cercospora species is a devastating maize disease. The cultivation of GLS-resistant hybrids is the most efficient way to control this disease. However, GLS resistance is a quantitatively inherited trait. Researchers led by Mingliang Xu of China Agricultural University now aim to map and characterize the quantitative trait loci (QTLs) for GLS resistance.

A major GLS resistance QTL, qRgls2, was previously detected in the centromere of chromosome 5. By using advanced backcross populations from the cross of the resistant and a susceptible line, a recombinant-derived progeny testing was done to fine map qRgls2. The region of qRgls2 was narrowed further, flanked by markers G346 and DD11.

The qRgls2 gene showed additive effects and significantly increased the resistance across multiple generations. A total of 15 genes were predicted in the mapped region. It is assumed that qRgls2 could be widely used to improve maize resistance to GLS.

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