Abstract
Abstract Efficient use of nitrogen inputs for concurrent improvements in grain yield and nitrogen use efficiency (NUE) has been recognized as a viable strategy for sustainable agriculture development. Yet, there is little research on the possible physiological basis of maize hybrid heterosis for NUE and measurable traits that are corresponding to the NUE heterosis. A field study was conducted for two years to evaluate the heterosis for NUE and determine the relationship between NUE and its physiological components. Two commercial hybrids, ‘Xianyu335’ and ‘Zhengdan958’, and their parental inbred lines, were grown at 0 (0 N) and 150 kg N ha −1 (150 N), in a randomized complete block design with four replications each year. Compared to their parental lines, both hybrids displayed a significant heterosis, up to 466%, for NUE. N internal efficiency (NIE) accounted for 52% of the variation in heterosis for NUE, while there was generally negligible heterosis for nitrogen recovery efficiency (NRE). Heterosis for NIE and thereby for NUE in maize was ascribed to (i) an earlier establishment of pre-anthesis source for N accumulation, which phenotypically exhibited as a faster leaf appearance rate with higher maximum LAI and photosynthetic nitrogen use efficiency; (ii) a larger amount of N being remobilized from the vegetative tissues, especially from leaves, during the grain filling. Phenotypically, there was notably a rapid reduction in post-anthesis specific weights of leaf and stalk, but with maintained functionally stay-green ear leaves; and (iii) a higher productive efficiency per unit grain N, which was characterized by a reduced grain N concentration and enhanced sink strength.
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Claims 8
Claim · model-written summary
Both maize hybrids displayed significant heterosis for NUE of up to 466% relative to their parental lines.
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Physiological Basis of Heterosis for Nitrogen Use Efficiency of Maize”
e1“Compared to their parental lines, both hybrids displayed a significant heterosis, up to 466%, for NUE”
e2“Two commercial hybrids, ‘Xianyu335’ and ‘Zhengdan958’, and their parental inbred lines”
Claim · model-written summary
N internal efficiency accounted for 52% of the variation in heterosis for NUE.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Physiological Basis of Heterosis for Nitrogen Use Efficiency of Maize”
e1“N internal efficiency (NIE) accounted for 52% of the variation in heterosis for NUE”
Claim · model-written summary
Heterosis for nitrogen recovery efficiency was generally negligible.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Physiological Basis of Heterosis for Nitrogen Use Efficiency of Maize”
e1“while there was generally negligible heterosis for nitrogen recovery efficiency (NRE)”
Claim · model-written summary
Heterosis for NIE and NUE was ascribed to an earlier establishment of pre-anthesis N accumulation source.
- Outcome
- Heterosis for NIE and thereby for NUEe1
- Qualifier
- an earlier establishment of pre-anthesis source for N accumulatione1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Physiological Basis of Heterosis for Nitrogen Use Efficiency of Maize”
e1“Heterosis for NIE and thereby for NUE in maize was ascribed to (i) an earlier establishment of pre-anthesis source for N accumulation, which phenotypically exhibited as a faster leaf appearance rate with higher maximum LAI and photosynthetic nitrogen use efficiency”
Claim · model-written summary
Heterosis for NUE involved a larger amount of N remobilized from vegetative tissues, especially leaves, during grain filling.
- Organ / stage
- leavese1
- Outcome
- remobilizede1
- Qualifier
- a larger amount of N being remobilized from the vegetative tissuese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Physiological Basis of Heterosis for Nitrogen Use Efficiency of Maize”
e1“(ii) a larger amount of N being remobilized from the vegetative tissues, especially from leaves, during the grain filling”
Claim · model-written summary
Post-anthesis specific weights of leaf and stalk showed a rapid reduction in heterotic maize hybrids.
- Organ / stage
- leaf and stalke1
- Outcome
- post-anthesis specific weights of leaf and stalke1
- Direction
- rapid reductione1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Physiological Basis of Heterosis for Nitrogen Use Efficiency of Maize”
e1“Phenotypically, there was notably a rapid reduction in post-anthesis specific weights of leaf and stalk, but with maintained functionally stay-green ear leaves”
Claim · model-written summary
Functional stay-green of ear leaves was maintained in heterotic maize hybrids.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Physiological Basis of Heterosis for Nitrogen Use Efficiency of Maize”
e1“Phenotypically, there was notably a rapid reduction in post-anthesis specific weights of leaf and stalk, but with maintained functionally stay-green ear leaves”
Claim · model-written summary
Heterosis for NUE involved higher productive efficiency per unit grain N, with reduced grain N concentration and enhanced sink strength.
- Outcome
- productive efficiency per unit grain Ne1
- Direction
- highere1
- Qualifier
- reduced grain N concentration and enhanced sink strengthe1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Physiological Basis of Heterosis for Nitrogen Use Efficiency of Maize”
e1“(iii) a higher productive efficiency per unit grain N, which was characterized by a reduced grain N concentration and enhanced sink strength”