Water Stress Impacts on Transgenic Drought-Tolerant Corn in the Northern Great Plains
2014
Chang, Jiyul | Clay, David E. | Hansen, Stephanie A. | Clay, Sharon A. | Schumacher, Thomas E.
The transgenic corn (Zea mays L.) drought-tolerant cultivar MON 87460 has the potential to increase grain production in high-water-deficit environments; however, these traits could also reduce yields when implemented in moderate- to high-yield environments. This study determined the influence of MON 87460, a corn cultivar that expresses the cold shock protein B, on corn grain yield, stover production, cob yields, root system declination, root/shoot ratios, root distribution, harvest index, and leaf area when grown in moderate- to high-yield environments. Research on MON 87460 and nontransgenic isolines was conducted at two South Dakota sites in 2009 and 2010. Root biomass and other samples were collected at silking and physiological maturity. The root/shoot ratios (including estimated root exudates) ranged from 0.40 to 0.78, and the belowground biomass contained in the surface 15 cm was 70% of the belowground biomass returned to the soil. Root declination ranged from 20 to 40°. There was no evidence to suggest that MON 87460 impacted shoot or root architecture or yield when grown in moderate- to high-yield environments. The measured root/shoot ratios were 0.54 g root g–¹ aboveground biomass, and the harvest indices were 0.52 g grain g–¹ aboveground biomass. Additional findings showed that for soil organic C maintenance calculations, 88.6 ± 0.6% of unharvested C should be added to the surface 15 cm, and that in 2009, root/shoot ratios were positively correlated with yield loss due to water stress (r = 0.39, P < 0.01) and were not correlated with either yield loss due to N stress (r = 0.16) or grain yield (r = 0.06).
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