Genetic Analysis of Maize Root Characteristics in Response to Low Nitrogen Stress |
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Authors: | Liang Chun Guohua Mi Jiansheng Li Fanjun Chen Fusuo Zhang |
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Institution: | (1) Key Lab of Plant–Soil Interaction, College of Resources and Environmental Sciences, P R China;(2) College of Agronomy and Biotechnique, China Agricultural University, 100094 Beijing, PR China |
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Abstract: | Under low-input cropping systems, nitrogen (N) can be a limiting factor in plant growth and yield. Identifying genotypes that
are more efficient at capturing limited N resources and the traits and mechanisms responsible for this ability is important.
Root trait has a substantial influence on N acquisition from soils. Nevertheless, inconsistencies still exist as to the effect
of low N on root length and its architecture in terms of lateral and axial roots. For maize, a crop utilizing heterosis, little
is known about the relationship between parents and their crosses in the response of root architecture to N availability.
Here 7 inbred maize lines and 21 of their crosses created by diallel mating were used to study the effect of N stress on root
morphology as well as the relationship between the inbreds and their crosses. With large genotypic differences, low N generally
suppresses shoot growth and increases the root to shoot ratio with or without increasing root biomass in maize. Maize plants
responded to N deficiency by increasing total root length and altering root architecture by increasing the elongation of individual
axial roots and enhancing lateral root growth, but with a reduction in the number of axial roots. Here, the inbreds showed
weaker responses in root biomass and other root parameters than their crosses. Heterosis of root traits was significant at
both N levels and was attributed to both the general combining ability (GCA) and special combining ability (SCA). Low N had
substantial affects on the pattern of heterosis, GCA and SCA affects on root traits for each of the crosses suggesting that
selection under N stress is necessary in generating low N-tolerant maize genotypes. |
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Keywords: | GCA maize (Zea Mays L ) nitrogen root morphology SCA |
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