Next Article in Journal
Artificial Seeds (Principle, Aspects and Applications)
Previous Article in Journal
Reducing Severity of Late Blight (Phytophthora infestans) and Improving Potato (Solanum tuberosum L.) Tuber Yield with Pre-Harvest Application of Calcium Nutrients
Open AccessArticle

Prospects for Genetic Improvement in Internal Nitrogen Use Efficiency in Rice

Southern Cross Plant Science, Southern Cross University, Lismore 2480, New South Wales, Australia
International Rice Research Institute (IRRI), DAPO Box 7777, Metro Manila 1301, Philippines
Crop, Livestock and Environment Division, Japan International Research Center for Agricultural Science, Tsukuba 305-8686, Ibaraki, Japan
Author to whom correspondence should be addressed.
Agronomy 2017, 7(4), 70;
Received: 13 September 2017 / Revised: 24 October 2017 / Accepted: 26 October 2017 / Published: 30 October 2017
While improving the efficiency at which rice plants take up fertiliser nitrogen (N) will be critical for the sustainability of rice (Oryza sativa L.) farming systems in future, improving the grain yield of rice produced per unit of N accumulated in aboveground plant material (agronomic N use efficiency; NUEagron) through breeding may also be a viable means of improving the sustainability of rice cropping. Given that NUEagron (grain yield/total N uptake) is a function of harvest index (HI; grain yield/crop biomass) × crop biomass/total N uptake, and that improving HI is already the target of most breeding programs, and specific improvement in NUEagron can only really be achieved by increasing the crop biomass/N uptake. Since rice crops take up around 80% of total crop N prior to flowering, improving the biomass/N uptake (NUEveg) prior to, or at, flowering may be the best means to improve the NUEagron. Ultimately, however, enhanced NUEagron may come at the expense of grain protein unless the N harvest index increases concurrently. We investigated the relationships between NUEagron, total N uptake, grain yield, grain N concentration (i.e., protein) and N harvest index (NHI) in 16 rice genotypes under optimal N conditions over two seasons to determine if scope exists to improve the NHI and/or grain protein, while maintaining or enhancing NUEagron in rice. Using data from these experiments and from an additional experiment with cv. IR64 under optimum conditions at an experimental farm to establish a benchmark for NUE parameters in high-input, high yielding conditions, we simulated theoretical potential improvements in NUEveg that could be achieved in both low and high-input scenarios by manipulating target NHIs and grain protein levels. Simulations suggested that scope exists to increase grain protein levels in low yielding scenarios with only modest (5–10%) reductions in current NUEagron by increasing the current NHI from 0.6 to 0.8. Furthermore, substantial scope exists to improve NUEveg (and therefore NUEagron) in high-yielding scenarios if maintaining current grain protein levels of 7.3% is not essential. View Full-Text
Keywords: grain protein; nitrogen harvest index; nutrient use efficiency; Oryza sativa grain protein; nitrogen harvest index; nutrient use efficiency; Oryza sativa
Show Figures

Figure 1

MDPI and ACS Style

Rose, T.J.; Kretzschmar, T.; Waters, D.L.E.; Balindong, J.L.; Wissuwa, M. Prospects for Genetic Improvement in Internal Nitrogen Use Efficiency in Rice. Agronomy 2017, 7, 70.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

Search more from Scilit
Back to TopTop