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Nitrogen (N) is a major driving force for crop yield improvement, but application of high levels of N delays flowering, prolonging maturation and thus increasing the risk of yield losses. Therefore, traits that enable utilization of high levels of N without delaying maturation will be highly desirable for crop breeding. Here, we show that OsNRT1.1A (OsNPF6.3), a member of the rice (Oryza sativa) nitrate transporter 1/peptide transporter family, is involved in regulating N utilization and flowering, providing a target to produce high yield and early maturation simultaneously. OsNRT.1A has functionally diverged from previously reported NRT1.1 genes in plants and functions in upregulating the expression of N utilization-related genes not only for nitrate but also for ammonium, as well as flowering-related genes. Relative to the wild type, osnrt1.1a mutants exhibited reduced N utilization and late flowering. By contrast, overexpression of OsNRT1.1A in rice greatly improved N utilization and grain yield, and maturation time was also significantly shortened. These effects were further confirmed in different rice backgrounds and also in Arabidopsis thaliana Our study paves a path for the use of a single gene to dramatically increase yield and shorten maturation time for crops, outcomes that promise to substantially increase world food security.

With increasing environmental pressure and soil pollution, sustainable energy and food production for a steadily growing world population is a grand challenge. Globally, nearly 12 million hectares of croplands are contaminated by cadmium (Cd), and how to develop a production system for the cleaning and utilisation of such contaminated land is essential for sustainability. Herein, a diverse panel of 166 sorghum accessions was grown in typical Cd-contaminated fields in two consecutive years, and the effect of different accessions and organs on the phytoremediation potential was evaluated by analysing the Cd concentrations of stems, leaves and grains at maturity. Both the bioaccumulation factors (BCFs) and the aboveground Cd accumulation varied substantially and the differences were up to 13–24 fold. The aboveground Cd accumulation was positively associated with important bioenergy traits including biomass, stem Brix, internode numbers and plant height, as envisaged by the high Cd concentration in sweet sorghum accessions, while BCF was significantly negatively correlated with relevant agronomic traits except Brix. The genetic regulation of Cd concentration in grains is different from those in leaves and stems, which allowed us to screen for three types of sorghum resources with the potential to couple soil phytoremediation with the production of bioethanol, safe grains and forage. A sorghum farming system was further proposed, which could reduce soil Cd concentration below the safe level within 12 years and obtain economic returns of about 70.5–169.5 million Chinese Yuan (CNY) by producing bioethanol, safe grains and forage in one season in 30% of the Cd-contaminated soil in China.

Closing the gap between yields currently achieved on farms and those that can potentially be achieved with best practice and current technology (the yield gap) is a key strategy to intensify grain production without expanding cropland. Much research has been done to quantify the yield gap of wheat, maize and rice globally and of wheat, barley, canola, sorghum and pulse crops in Australia. However, crops are grown in rotations (recurring crop sequences) that vary in their cropping intensities and in the diversity of their species. Little is known about yield gaps at the cropping system level, especially in regions where there are many possible combinations of crop types and fallow periods. This prompted us to investigate crop rotations in Australia's subtropical grains region where current crop rotations include winter and summer cropping with cereal, pulse and oilseed crops interspersed with fallow periods ranging from nil to 18 months duration. To determine the system level yield gaps, we simulated the water-limited yield potential of 26 locally practiced crop rotations for over 800 weather stations by up to 3 soil types per station. We captured the impact of climate variability with 30–35 years by 2–7 fields per rotation for each site. We expressed the results in terms of energy, protein and revenue per hectare per year and mapped the results of the optimal rotations over the cropping zone. Surprisingly, a single rotation (sorghum/fallow/mungbean/wheat/fallow/chickpea rotation; with 4 crops in 3 years, balanced between summer and winter crops and between cereal and pulse crops) was optimal for revenue over almost the whole subtropical grain zone. Using revenue as the metric for yield gaps at statistical local area scale we found, over the whole subtropical zone, a mean revenue gap of 970 $/ha/yr. This represents a relative revenue (Revenue% = 100 x (actual revenue/water-limited revenue)) of 34% which is much lower than expected from the 40–60% relative yields achieved by individual crops. We investigated whether growers may select rotations that have lower revenue than the optimal rotation in response to economic factors such as profit and risk. We found that for much of the area the same rotation that optimised revenue also optimised profit. However, for some of the cropping zone, particularly in the south western portion, a different, less intensive and more winter dominant, rotation was most profitable. Similarly, risk averse farmers may choose less productive and profitable rotations with less risk.