Genetic approaches to enhancing nitrogen-use efficiency (NUE) in cereals: challenges and future directions

2015 ◽  
Vol 42 (10) ◽  
pp. 921 ◽  
Author(s):  
Trevor Garnett ◽  
Darren Plett ◽  
Sigrid Heuer ◽  
Mamoru Okamoto

Over 100 million tonnes of nitrogen (N) fertiliser are applied globally each year to maintain high yields in agricultural crops. The rising price of N fertilisers has made them a major cost for farmers. Inefficient use of N fertiliser leads to substantial environmental problems through contamination of air and water resources and can be a significant economic cost. Consequently, there is considerable need to improve the way N fertiliser is used in farming systems. The efficiency with which crops use applied N fertiliser – the nitrogen-use efficiency (NUE) – is currently quite low for cereals. This is the case in both high yielding environments and lower yielding environments characteristic of cereal growing regions of Australia. Multiple studies have attempted to identify the genetic basis of NUE, but the utility of the results is limited because of the complex nature of the trait and the magnitude of genotype by environment interaction. Transgenic approaches have been applied to improve plant NUE but with limited success, due, in part, to a combination of the complexity of the trait but also due to lack of accurate phenotyping methods. This review documents these two approaches and suggests future directions in improving cereal NUE with a focus on the Australian cereal industry.

2015 ◽  
Vol 12 (22) ◽  
pp. 18883-18911 ◽  
Author(s):  
X. Zhang ◽  
Z. Zhou ◽  
Y. Liu ◽  
X. Xu ◽  
J. Wang ◽  
...  

Abstract. Our understanding of how net global warming potential (NGWP) and greenhouse gas intensity (GHGI) is affected by management practices aimed at food security with respect to rice agriculture remains limited. In the present study, a 5 year field experiment was conducted in China to evaluate the effects of integrated soil-crop system management (ISSM) on NGWP and GHGI after accounting for carbon dioxide (CO2) emissions from all sources (methane, CH4, and nitrous oxide, N2O, emissions, agrochemical inputs, Ei, and farm operations, Eo) and sinks (i.e., soil organic carbon, SOC, sequestration). For the improvement of rice yield and agronomic nitrogen use efficiency (NUE), four ISSM scenarios consisting of different nitrogen (N) fertilization rates relative to the local farmers' practice (FP) rate were carried out, namely, N1 (25 % reduction), N2 (10 % reduction), N3 (FP rate) and N4 (25 % increase). The results showed that compared with the FP, the four ISSM scenarios, i.e., N1, N2, N3 and N4, significantly increased the rice yields by 10, 16, 28 and 41 % and the agronomic NUE by 75, 67, 86 and 82 %, respectively. In addition, compared with the FP, the N1 and N2 scenarios significantly reduced the GHGI by 14 and 18 %, respectively, despite similar NGWPs. The N3 and N4 scenarios remarkably increased the NGWP and GHGI by an average of 67 and 36 %, respectively. In conclusion, the ISSM strategies are promising for both food security and environmental protection, and the ISSM scenario of N2 is the optimal strategy to realize high yields and high NUE together with low environmental impacts for this agricultural rice field.


2016 ◽  
Vol 67 (11) ◽  
pp. 1139 ◽  
Author(s):  
Giao N. Nguyen ◽  
Joe Panozzo ◽  
German Spangenberg ◽  
Surya Kant

Nitrogen (N) is a key mineral element required for crop growth, yield and quality. Nitrogen-use efficiency (NUE) in crop plants is low despite significant research efforts. Excessive use of N fertiliser results in significant economic cost and contributes to environmental pollution. Therefore, it is crucial to develop crop varieties with improved NUE, and this requires efficient phenotyping approaches to screen genotypes under defined N conditions. To address this, 15 wheat (Triticum aestivum L.) varieties, grown under three N levels, were phenotyped for NUE-related traits under field conditions. Significant genotypic differences were observed in varieties having low to high responsiveness to N applications. The results suggest that basal low N can be used to screen wheat varieties that are less responsive to N, whereas N supply from 80 to 160 kg N ha–1 could be used to screen high N-responsive varieties. Normalised difference vegetation index (NDVI) measured by using Crop Circle, and SPAD units measured by SPAD meter at heading stage, were well correlated with shoot dry biomass, grain yield, and shoot and grain N concentration, and could potentially be used as tools to phenotype different wheat varieties under varying N treatments. The data also demonstrated that NDVI and SPAD could be used to differentiate wheat varieties phenotypically for NUE-related traits. The prospect of utilising efficient, non-destructive phenotyping to study NUE in crops is also discussed.


2016 ◽  
Vol 105 (1) ◽  
pp. 1-23 ◽  
Author(s):  
Hung-Chun Lin ◽  
Julia A. Huber ◽  
Georg Gerl ◽  
Kurt-Jürgen Hülsbergen

2016 ◽  
Vol 13 (9) ◽  
pp. 2701-2714 ◽  
Author(s):  
Xiaoxu Zhang ◽  
Xin Xu ◽  
Yinglie Liu ◽  
Jinyang Wang ◽  
Zhengqin Xiong

Abstract. Our understanding of how global warming potential (GWP) and greenhouse gas intensity (GHGI) is affected by management practices aimed at food security with respect to rice agriculture remains limited. In the present study, a field experiment was conducted in China to evaluate the effects of integrated soil–crop system management (ISSM) on GWP and GHGI after accounting for carbon dioxide (CO2) equivalent emissions from all sources, including methane (CH4) and nitrous oxide (N2O) emissions, agrochemical inputs and farm operations and sinks (i.e., soil organic carbon sequestration). The ISSM mainly consisted of different nitrogen (N) fertilization rates and split, manure, Zn and Na2SiO3 fertilization and planting density for the improvement of rice yield and agronomic nitrogen use efficiency (NUE). Four ISSM scenarios consisting of different chemical N rates relative to the local farmers' practice (FP) rate were carried out, namely, ISSM-N1 (25 % reduction), ISSM-N2 (10 % reduction), ISSM-N3 (FP rate) and ISSM-N4 (25 % increase). The results showed that compared with the FP, the four ISSM scenarios significantly increased the rice yields by 10, 16, 28 and 41 % and the agronomic NUE by 75, 67, 35 and 40 %, respectively. In addition, compared with the FP, the ISSM-N1 and ISSM-N2 scenarios significantly reduced the GHGI by 14 and 18 %, respectively, despite similar GWPs. The ISSM-N3 and ISSM-N4 scenarios remarkably increased the GWP and GHGI by an average of 69 and 39 %, respectively. In conclusion, the ISSM strategies are promising for both food security and environmental protection, and the ISSM scenario of ISSM-N2 is the optimal strategy to realize high yields and high NUE together with low environmental impacts for this agricultural rice field.


2018 ◽  
Vol 93 ◽  
pp. 40-49 ◽  
Author(s):  
Ning An ◽  
Wenliang Wei ◽  
Lei Qiao ◽  
Fusuo Zhang ◽  
Peter Christie ◽  
...  

2020 ◽  
Vol 51 (4) ◽  
pp. 1139-1148
Author(s):  
Othman & et al.

The research work was conducted in Izra’a Research station, which affiliated to the General Commission for Scientific Agricultural Research (GCSAR), during the growing seasons (2016 – 2017; 2017 – 2018), in order to evaluate the response of two durum wheat verities (Douma3 and Cham5) and two bread wheat varieties (Douma4 and Cham6) to Conservation Agriculture (CA) as a full package compared with Conventional Tillage system (CT) under rainfed condition using lentils (Variety Edleb3) in the applied crop rotation. The experiment was laid according to split-split RCBD with three replications. The average of biological yield, grain yield,  rainwater use efficiency and nitrogen use efficiency was significantly higher during the first growing season, under conservation agriculture in the presence of crop rotation, in the variety Douma3 (7466 kg. ha-1, and 4162kg. ha-1, 19.006 kg ha-1 mm-1,  39.62 kg N m-2respectively). The two varieties Douma3 and Cham6 are considered more responsive to conservation agriculture system in the southern region of Syria, because they recorded the highest grain yields (2561, 2385 kg ha-1 respectively) compared with the other studied varieties (Cham5 and Douma4) (1951 and 1724 kg ha-1 respectively). They also exhibited the highest values of both rainwater and nitrogen use efficiency.


2015 ◽  
Vol 41 (3) ◽  
pp. 422 ◽  
Author(s):  
Cheng-Xin JU ◽  
Jin TAO ◽  
Xi-Yang QIAN ◽  
Jun-Fei GU ◽  
Bu-Hong ZHAO ◽  
...  

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