Measurement of Nitrogen Utilization Efficiency in Rice Genotypes 1

Shibato

Physiol Mol Biol Plants

et al. 2009

Nitrogen fertilization is essential for increasing rice production to meet the food demands of increasing world's population. We established an in vivo hydroponic rice seedling culture system to investigate physio-biochemical/molecular responses of various rice japonica and indica cultivars to low nitrogen (N). Three-week-old seedlings grown in Yoshida's nutrient solution manifested stable and reproducible symptoms, such as reduced shoot growth and length under low N. Out of 12 genetically selected cultivars, 11 cultivars showed varied degrees of growth reduction response to applied N (4 and 40 ppm N for treatment and control, respectively), whereas one cultivar (no. 12) showed similar growth as the control though its leaf width was smaller than control. Leaves of a representative low N-responsive cultivar (BG90-2) were sampled for revealing protein profiles between low and normal (control) N application by two-dimensional gel electrophoresis (2-DGE). Forty-one proteins were identified with MALDI-TOF-MS and nESI-LC-MS/MS. Assignment of proteins into major (energy metabolism, photosynthesis and oxidative stress) and minor functional categories, revealed many novel low N-responsive proteins, including those having energy/photosynthesis-and defense/stress-and iron homeostasis-related functions. Results suggest the usefulness of proteomics in identifying novel N-responsive proteins and may provide potential markers for rice response to low N.

Section: Introductionmentioning

confidence: 99%

Gel-based proteomics approach for detecting low nitrogen-responsive proteins in cultivated rice species

Shibato

Physiol Mol Biol Plants

et al. 2009

Scale and Complexity in Plant Systems Research

“…Broadbent et al (1987) studied NUE g of 24 genotypes with and without fertilizer-N application. They estimated NUE g using the ratio of panicle weight to total N uptake (WP/TN) and reported that there were significant differences in WP/TN among the genotypes.…”

Section: Genotypic Variation In Nitrogen Use Efficiencymentioning

confidence: 99%

“…Crop growth duration affects NUE g through influencing crop yield and N uptake. Medium-duration genotypes had higher NUE g than short-duration genotypes (Broadbent et al 1987;De Datta and Broadbent 1990). Longer duration could result in a decrease in NUE g (Samonte et al 2006).…”

Section: Plant Traits Related To Nitrogen Use Efficiencymentioning

confidence: 99%

“…Koutroubas and Ntanos (2003) argued that using single selection criteria for improving NUE may have negative implications on grain yield because of interaction among NUE-related traits. Broadbent et al (1987) stated that the evaluation of NUE of different genotypes should be based on multiple parameters rather than just one parameter. The sum of Z-transformed values of grain yield, NUE g , panicle weight, panicle weight/total N uptake and total dry matter/total N uptake, putting equal weights on each parameter, was used to rank genotypes (Broadbent et al 1987;De Datta and Broadbent 1988;1990).…”

Section: Plant Traits Related To Nitrogen Use Efficiencymentioning

confidence: 99%

“…Broadbent et al (1987) stated that the evaluation of NUE of different genotypes should be based on multiple parameters rather than just one parameter. The sum of Z-transformed values of grain yield, NUE g , panicle weight, panicle weight/total N uptake and total dry matter/total N uptake, putting equal weights on each parameter, was used to rank genotypes (Broadbent et al 1987;De Datta and Broadbent 1988;1990). Singh et al (1998) developed the N productivity index (NPI), which is the product of grain yield at zero N and NUE g for evaluating NUE of genotypes.…”

Section: Plant Traits Related To Nitrogen Use Efficiencymentioning

confidence: 99%

See 2 more Smart Citations

Prospects for Genetic Improvement to Increase Lowland Rice Yields with Less Water and Nitrogen

Peng¹,

Bouman²

Abstract. Increasing yield potential of lowland rice remains to be the top priority in rice geneticimprovement programmes, because rice farmers' primary concern is still grain yield and world rice production has to increase by 1% annually in the next 20 years to meet the demand of the growing population. Improvements in yield potential of irrigated lowland rice were achieved under ample supply of water and nutrients. Water use efficiency (WUE) and nitrogen use efficiency (NUE) were seldom included in the breeding objectives for irrigated lowland rice. Scarcity of freshwater resources has threatened the production of the flood-irrigated rice crop, and excessive use of N fertilizer is causing environmental concerns. We have to increase lowland rice yield with less water and N. Newly developed crop management strategies have proven to be effective in increasing WUE and NUE. Several watersaving technologies such as alternate wetting and drying (AWD) and aerobic rice system have been developed to increase the water productivity of rice. However, yield penalty occurred when these watersaving technologies were practised with current varieties. New varieties have to be developed to reduce the yield loss under AWD and aerobic rice system in order to increase WUE further. Direct selection for WUE under flood-irrigated lowland conditions may have a negative impact on grain yield under watersaving strategies. Optimizing the timing and rate of N application to synchronize supply and demand of N by the crop has resulted in a great reduction in fertilizer-N input without yield loss and greater NUE. Genetic improvement of NUE has not been achieved in rice. Genotypic variation in NUE has been reported in many studies. Plant traits that are associated with high grain yield and high NUE should be identified so that breeders are able to use these traits easily as selection criteria in the breeding programme to develop N-efficient varieties without sacrificing rice yield potential. New breeding techniques such as development of F 1 hybrids, marker-aided selection, transformation and genetic engineering should be combined effectively with the empirical breeding method in order to increase rice grain yield with less water and N.

The Molecular and Physiological Basis of Nutrient Use Efficiency in Crops

Crop Improvement for Nitrogen Use Efficiency in Irrigated Lowland Rice

Peng

2011

There is an urgent need to develop superior nitrogen -effi cient rice varieties because of poor fertilizer nitrogen use effi ciency (NUE), associated economic and environmental concerns, and the lack of adoption of improved nitrogen management practices. Genotypic variation in NUE has been reported for rice in many studies. The physiological mechanisms underlying both nitrogen uptake effi ciency and utilization effi ciency are fairly well understood. Plant traits that are closely associated with NUE have been identifi ed. In general, there is a positive relationship between grain yield and NUE, suggesting that it is possible to develop rice varieties with both high grain yield and high NUE. An empirical breeding method can be used for developing nitrogeneffi cient varieties using existing genotypic variation in NUE. However, for signifi cant improvement in NUE, new breeding techniques such as the development of F 1 hybrids, marker -aided selection, transformation, and genetic engineering should be considered.