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Maize(Zea mays L.) root morphology exhibits a high degree of phenotypic plasticity to nitrogen(N) de ficiency,but the underlying genetic architecture remains to be investigated Using an advanced BC_4F_3 population,we investigated the root growth plasticity under two contrasted N levels and identi fied the quantitative trait loci(QTLs) with QTL-environment(Q×E)interaction effects. Principal components analysis(PCA) on changes of root traits to N de ficiency(D LN-HN) showed that root length and biomass contributed for 45.8% in the same magnitude and direction on the first PC,while root traits scattered highly on PC_2 and PC_3. Hierarchical cluster analysis on traits for D LN-HN further assigned the BC_4F_3 lines into six groups,in which the special phenotypic responses to N de ficiency was presented These results revealed the complicated root plasticity of maize in response to N de ficiency that can be caused by genotype environment(G×E) interactions. Furthermore,QTL mapping using a multi-environment analysis identi fied 35 QTLs for root traits. Nine of these QTLs exhibited signi ficant Q×E interaction effects. Taken together,our findings contribute to understanding the phenotypic and genotypic pattern of root plasticity to N de ficiency,which will be useful for developing maize tolerance cultivars to N de ficiency.
Maize (Zea mays L.) root morphology exhibits a high degree of phenotypic plasticity to nitrogen (N) de ficiency, but the underlying genetic architecture remains to be investigated using an advanced BC_4F_3 population, we investigated the root growth plasticity under two contrasted N levels and identi fied the quantitative trait loci (QTLs) with QTL-environment (Q × E) interaction effects. Principal components analysis (PCA) on changes of root traits to N de ficiency (D LN-HN) showed that root length and biomass for 45.8% in the same magnitude and direction on the first PC, while root traits scattered highly on PC_2 and PC_3. Hierarchical cluster analysis on traits for D LN-HN further assigned the BC_4F_3 lines into six groups, in which the special phenotypic responses to N de ficiency was presented These results revealed the complicated root plasticity of maize in response to N de ficiency that can be caused by genotype environment (G × E) interactions. Furthermore, QTL mapping using a mu lti-environment analysis identi fied 35 QTLs for root traits. Nine of these QTLs demonstrate signi ficant Q × E interaction effects. Taken together, our findings contribute to understanding the phenotypic and genotypic pattern of root plasticity to N de ficiency, which will be useful for developing maize tolerance cultivars to N de ficiency.