Book with abstracts from the COST Action 0905 meeting in ... - UMB

HOW DOES THE GREEN REVOLUTION AFFECT MINERAL
CONCENTRATIONS IN WHEAT GRAIN?
Fang-Jie Zhao 1 , Mike J. Gooding 2 , Mingsheng Fan 1 , Steve P. McGrath 1 , Peter R. Shewry 1
1
Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
2
School of Agriculture, Policy and Development, The University of Reading, Earley Gate,
Reading, RG6 6AR, UK
Keywords: Rht alleles, Wheat grain, Mineral concentration, Nitrogen fertilizer,
Green revolution
Using the Broadbalk long-term (>160 years) experiment at Rothamsted, we found that the
concentrations of zinc, iron, copper and magnesium in wheat grain have decreased
significantly since the mid 1960s, which coincided with the introduction of semi-dwarf,
high-yielding cultivars, the so-called Green Revolution. Furthermore, mineral
concentrations were also lower in new cultivars than in old ones in a study including 150
cultivars of diverse origin. Here we investigate the effect of dwarfing alleles on mineral
concentrations in wheat under field and glasshouse conditions. In the field trial, the
gibberellin-insensitive reduced height allele Rht-B1b increased crop biomass, dry matter
(DM) harvest index and grain yield, but did not increase the uptake of Cu, Fe, Mg or Zn so
these minerals were diluted in grain. In contrast, nitrogen increased both DM yield and
mineral uptake so grain concentrations were either increased (Fe, Cu) or only slightly
affected (Mg, Zn). In the glasshouse experiment, the Rht alleles decreased grain yield and
increased mineral concentrations in grain. We conclude that the effects of Rht alleles on
mineral concentrations in wheat grain are mostly indirect due to their effects on DM,
resulting in either dilution or concentration of minerals in grain. In semi-dwarf varieties,
increased N requirement and N applications partly offsets this dilution effect.