Greater lateral root branching density in maize (Zea mays L.) improves phosphorus acquisition from low phosphorus soil


Xucun Jia, Peng Liu & Jonathan P. Lynch


Journal of Experimental Botany

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The development of crops with better growth under suboptimal phosphorus  availability would improve food security in developing countries while reducing  environmental pollution in developed countries. We tested the hypothesis that  maize (Zea mays) phenotypes with greater lateral root branching density have greater phosphorus acquisition from low phosphorus soils. Recombinant inbred  lines with either ‘many short’ (MS) or ‘few long’ (FL) lateral root phenotypes were  grown under high and low phosphorus conditions in greenhouse mesocosms and  in the field. Under low phosphorus in mesocosms, lines with the MS phenotype  had 89% greater phosphorus acquisition and 48% more shoot biomass than FL  lines. Under low phosphorus in the field, MS lines had 16% shallower rooting depth  (D95), 81% greater root length density in the top 20 cm of the soil, 49% greater  shoot phosphorus content, 12% greater leaf photosynthesis, 19% greater shoot  biomass and 14% greater grain yield than FL lines. These results are consistent  with the hypothesis that the phenotype of many, shorter lateral roots improves  phosphorus acquisition under low phosphorus availability and merits consideration for genetic improvement of phosphorus efficiency in maize and other crops.