Effects of Soil Compaction and Meloidogyne incognita on Cotton Root Architecture and Plant Growth

Jianbing Ma, Terrence L. Kirkpatrick, Craig S. Rothrock, Kristofor Byre

Abstract


The effects of a soil hardpan and Meloidogyne incognita on cotton root architecture and plant growth were evaluated inmicroplots in 2010 and 2011. Soil was infested with M. incognita at four different levels with or without a hardpan. The presence ofa hardpan resulted in increased plant height, number of main stem nodes, and root fresh weight for cotton seedlings both years.Meloidogyne incognita decreased height and number of nodes for seedlings in 2010. Nematode infestation increased seedling rootlength and enhanced root magnitude, altitude, and exterior path length in 2010. This was also the case for root length andmagnitude in 2011 at lower infestation levels suggesting compensatory growth. A hardpan had no consistent effect on these rootparameters but increased root volume in both years. A hardpan hastened crop maturity and increased the number of fruitingbranches that were produced, while M. incognita infection delayed crop development and reduced plant height and number of bolls.Both M. incognita infection and a hardpan reduced taproot length and root dry weight below the hardpan in both years. Roottopological indices under all the treatments ranged from 1.71 to 1.83 both years indicating that root branching followed a herringbonepattern. The techniques for characterizing root architecture that were used in this study provide a greater understanding ofchanges that result from disease and soil abiotic parameters affecting root function and crop productivity.

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