Although the genotypic variation of nutrient use efficiency of bread wheat has been a focus of many previous studies, this variation may largely depend on the growth environment and the range of wheat cultivars being investigated. The present study aimed to examine the influence of the growth environment on the genotypic variation of nutrient use efficiency of wheat, the relationship between nutrient use efficiency parameters and yield or grain quality, and the changes in nutrient use efficiency parameters with wheat breeding history. We conducted a two-year field experiment at four different sites, and the genotypic variation of 12 nitrogen (N), phosphorus (P) and potassium (K) use efficiency parameters (NUE, PUE and KUE) were investigated in a large wheat diversity panel composed of 437 wheat cultivars released over more than 150 years. Compared with previous reports, our study expanded the lower limits of the ranges of nutrient use efficiency parameters. The NUE parameters were strongly positively correlated with the corresponding PUE parameters. Yield showed significant positive genetic correlations with most nutrient use efficiency parameters and was more strongly correlated with nutrient uptake efficiency. There was no significant genetic correlation between NUE, PUE or KUE with grain N concentration. Compared to tall cultivars, semi-dwarf wheat cultivars had higher P, K harvest index, N, K grain production efficiency. N harvest index, N, P uptake efficiency of the semi-dwarf cultivars slowly increased along with breeding history, and the relationships with breeding history for other parameters are largely environmental dependent. In conclusion, the greater genotypic variation of nutrient use efficiency of wheat revealed in our study provides insights into the improvement of nutrient-efficient wheat cultivar breeding. NUE and PUE could be improved simultaneously through wheat breeding. The nutrient harvest index, nutrient uptake and grain production efficiency could be target traits for nutrient-efficient wheat cultivar breeding.

This study analyzes dynamic changes in fossil energy input, energy output and fossil energy use efficiency in crop production in Hunan province, China, from 2010 to 2019 to determine the factors contributing to fossil energy use efficiency in crop production. The results showed that energy input decreased from 19.98 to 18.13 GJ ha-1 from 2010 to 2019, whereas energy output increased from 64.57 to 69.57 GJ ha-1. Energy use efficiency was estimated at 3.23 in 2010 and increased to 3.84 in 2019. The application of fertilizers (nitrogen and phosphorus) and pesticides was decreased, while the application of compound fertilizers was increased from 1.00 to 1.43 GJ ha-1 with a steady energy input during the study period. The yield of advantageous industry crops in Hunan province (cereals, oil-bearing crops, vegetables and fruits) was increased, while other crops (fiber crops, beans, sugarcane, tubers, tobacco and cotton) showed an indiscernible pattern. Our results indicate that developing countries need to promote the production and application of compound fertilizers to reduce energy input, develop competitive industries to increase energy output, adopt policies to optimize crop production structure and establish sustainable agricultural production systems.

Maize is an important feed and industrial cereal crop and is crucial for global food security. The development of drought-tolerant genotypes is a major aim of breeding programs to fight water scarcity and maintain sustainable maize production. Late embryogenesis abundant (LEA) proteins are a family of proteins related to osmotic regulation that widely exist in organisms. Here, we implemented a previously generated maize transcriptomic dataset to identify a drought-responsive gene designated ZmNHL1. Bioinformatics analysis of ZmNHL1 showed that the protein encoded by ZmNHL1 belongs to the LEA-2 protein family. Tissue specific expression analysis showed that ZmNHL1 is relatively abundant in stems and leaves, highly expressed in tassels and only slightly expressed in roots, pollens and ears. Moreover, the activity of SOD and POD of plants from three 35S::ZmNHL1 transgenic lines under either the …