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Title: Abiotic stress growth conditions induce different responses in kernel iron concentration across genotypically distinct maize inbred varieties

item KANDIANIS, CATHERINE - Children'S Nutrition Research Center (CNRC)
item MICHENFELDER, ABIGAIL - University Of North Carolina
item SIMMONS, SUSAN - University Of North Carolina
item Grusak, Michael
item STAPLETON, ANN - University Of North Carolina

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/11/2013
Publication Date: 12/4/2013
Citation: Kandianis, C.B., Michenfelder, A.S., Simmons, S.J., Grusak, M.A., Stapleton, A.E. 2013. Abiotic stress growth conditions induce different responses in kernel iron concentration across genotypically distinct maize inbred varieties. Frontiers in Plant Science. 4:488.

Interpretive Summary: Corn is an important grain crop that provides energy, protein, minerals, and vitamins for humans. Grain quality, however, can be affected by growing conditions, such as soil fertility and water availability. Because we would like to develop new, improved corn varieties of the highest potential nutritional value, we were interested in understanding how different environmental conditions might affect grain mineral concentrations, and iron concentration in particular. We grew several diverse corn varieties in field plots that were provided with full nitrogen nutrition and ample water, or were limited in nitrogen, water, or both. We found that the corn varieties with the highest iron concentration differed, depending on the environmental conditions they were grown under. This work tells us that breeding for improved grain nutritional quality will require testing under a range of field conditions and environments. Our results are promising because they will help us understand which environments are most important to make meaningful nutritional improvements in future corn varieties.

Technical Abstract: The improvement of grain nutrient profiles for essential minerals and vitamins through breeding strategies is a target important for agricultural regions where nutrient poor crops like maize contribute a large proportion of the daily caloric intake. Kernel iron concentration in maize exhibits a broad range. However, the magnitude of genotype by environment (GxE) effects on this trait reduces the efficacy and predictability of selection programs, particularly when challenged with abiotic stress such as water and nitrogen limitations. Selection has also been limited by an inverse correlation between kernel iron concentration and the yield component of kernel size in target environments. Using 25 maize inbred lines for which extensive genome sequence data is publicly available, we evaluated the response of kernel iron density and kernel mass to water and nitrogen limitation in a managed field stress experiment using a factorial design. To further understand GxE interactions we used partition analysis to characterize response of kernel iron and weight to abiotic stressors among all genotypes, and observed two patterns: one characterized by higher kernel iron concentrations in control over stress conditions, and another with higher kernel iron concentration under drought and combined stress conditions. Breeding efforts for this nutritional trait could exploit these complementary responses through combinations of favorable allelic variation from these already well-characterized genetic stocks.