Compared with single agronomic practices management during grain formation, knowledge about integrated agronomic practices management on grain-filling characteristics and physiological function of endogenous hormones was limited.  In order to clarify this issue, two field experiments, integrated agronomic practices management (IAPM), T1 (local conventional cultivation practices), T2 (an optimized combination of cropping systems and fertilizer treatment), T3 (treatment based on high-yield studies), and T4 (further optimized combination of cropping systems and fertilizer treatment), and nitrogen rate testing (NAT) (four nitrogen rates, 0, 129.0, 184.5, and 300.0 kg N ha^–1) were performed with summer maize hybrid Zhengdan 958 (ZD958). Results showed that with increased nitrogen rate, the endogenous hormone balance was promoted and the grain-filling characteristics were improved sufficiently to resulting in a significant increase in grain yield.  However, the grain-filling characteristics deteriorated and yield was reduced with excessive nitrogen fertilization.  However, IAPM could promote hormone balance and improve grain filling characteristic.  The indole-3-acetic acid (IAA), zeatin riboside (ZR), and gibberellin (GA₃) contents under T2 and T4 treatments were higher and the abscisic acid (ABA) content was lower, and the ZR and GA₃ contents under T3 were higher than those under T1.  Those resulted in the maximum grain-filling rate (W_max) and the active grain-filling period (P) under T2, T3 and T4 were significantly increased than those under T1, and hence promoted kernel weight and grain yield.  So IAPM promoted hormone balance by improving tillage model, optimizing fertilizer rate and fertilization period, appropriately increasing planting density and delaying harvest, which promoted grain filling rate and lengthened active grain-filling period, finally increased grain yield.

      Planting at an optimum density and supplying adequate nitrogen (N) to achieve higher yields is a common practice in crop production, especially for maize (Zea mays L.); however, excessive N fertilizer supply in maize production results in reduced N use efficiency (NUE) and severe negative impacts on the environment. This research was conducted to determine the effects of increased plant density and reduced N rate on grain yield, total N uptake, NUE, leaf area index (LAI), intercepted photosynthetically active radiation (IPAR), and resource use efficiency in maize. Field experiments were conducted using a popular maize hybrid Zhengdan 958 (ZD958) under different combinations of plant densities and N rates to determine an effective approach for maize production with high yield and high resource use efficiency. Increasing plant density was clearly able to promote N absorption and LAI during the entire growth stage, which allowed high total N uptake and interception of radiation to achieve high dry matter accumulation (DMA), grain yield, NUE, and radiation use efficiency (RUE). However, with an increase in plant density, the demand of N increased along with grain yield. Increasing N rate can significantly increase the DMA, grain yield, LAI, IPAR, and RUE. However, this increase was non-linear and due to the input of too much N fertilizers, the efficiency of N use at N_CK (320 kg ha^–1) was low. An appropriate reduction in N rate can therefore lead to higher NUE despite a slight loss in grain production. Taking into account both the need for high grain yield and resource use efficiency, a 30% reduction in N supply, and an increase in plant density of 3 plants m^–2, compared to LD (5.25 plants m^–2), would lead to an optimal balance between yield and resource use efficiency.

Stripe rust is a serious foliar disease posing a grave threat to wheat production worldwide.  The most economical and environmentally friendly way to control this disease is to breed and deploy resistant cultivars.  Zhongmai 175 is an elite winter wheat cultivar conferring resistance to a broad spectrum of Puccinia striiformis f. sp. tritici (Pst) races.  To identify the resistance gene in the cultivar, genetic analysis was conducted using the parents, F₁, F₂ and F_2:3 populations derived from the cross of Lunxuan 987/Zhongmai 175.  Segregations in the F₂ and F_2:3 populations indicated a single dominant gene conferring resistance to stripe rust in Zhongmai 175, temporarily designated YrZM175.  Bulked segregant analysis (BSA) with wheat iSelect 90K SNP array determined a preliminary location of YrZM175.  Subsequently, YrZM175 was mapped on chromosome 2AS using simple sequence repeats (SSR), expressed sequence tags (EST) and newly-developed kompetitive allele specific PCR (KASP) markers, being flanked by Xgwm636 and Xwmc382 at genetic distances of 4.9 and 8.1 cM, respectively.  Comparison of reaction patterns of YrZM175 on 23 Pst races or isolates and pedigree analysis with other genes on chromosome 2AS suggested that it is likely to be a new gene for resistance to stripe rust.  The resistance gene and linked molecular markers will be useful in wheat breeding targeting for the improvement of stripe rust resistance.

The combination of 1,3-dichloropropene+dimethyl disulfide (1,3-D+DMDS), which forms a pre-plant soil fumigant, can provide a substitute for the environmentally unfriendly methyl bromide (MB). Three greenhouse trials were performed to evaluate the root-knot nematode and soilborne fungi control efficacy in the suburbs of Beijing in China in 2010-2014. Randomized blocks with three replicates were designed in each trial. The combination of 1,3-D+DMDS (10+30 g m−2) significantly controlled Meloidogyne incognita, effectively suppressed the infestation of Fusarium oxysporum and Phytophthora spp., and successfully provided high commercial fruit yields (equal to MB but higher than 1,3-D or DMDS). The fumigant soil treatments were significantly better than the untreated controls. These results indicate that 1,3-D+DMDS soil treatments can be applied by soil injection or chemigation as a promising MB alternative against soilborne pests in cucumber in China.

As the most important organ in plant photosynthesis, the leaf plays an important role in plant growth and development. Leaf senescence is associated with fundamental changes in the proteome. To research the molecular mechanisms of leaf senescence, protein expression in senescing maize ear leaves grown under field conditions was analyzed using two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionisation time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/TOF MS). A total of 60 senescence-associated proteins were identified. The identified proteins are involved in many biological processes, especially energy, metabolism and protein synthesis. Several of the identified proteins have not been previously reported as senescence-associated, including glycine-rich RNA-binding protein.

The grain yield of maize has increased continuously in past decades, largely through hybrid innovation, cultivation technology, and in particular, recent genetic improvements in photosynthesis. Elite inbred lines are crucial for innovating new germplasm. Here, we analyzed variations in grain yield and a series of eco-physiological photosynthetic traits after anthesis in sixteen parental lines of maize (Zea mays L.) released during three different eras (1960s, 1980s, 2000s). We found that grain yield and biomass significantly increased in the 2000s than those in the 1980s and 1960s. Leaf area, chlorophyll, and soluble protein content slowly decreased, and maintained a higher net photosynthesis rate (Pn) and improved stomatal conductance (Gs) after anthesis in the 2000s. In addition, the parental lines in the 2000s obtained higher actual photochemistry efficiency (ФPSII) and the maximum PSII photochemistry efficiency (Fv/Fm), which largely improved light partitioning and chlorophyll fluorescence characteristic, including higher photochemical and photosystem II (PSII) reaction center activity, lower thermal energy dissipation in antenna proteins. Meanwhile, more lamellae per granum within chloroplasts were observed in the parental lines of the 2000s, with a clear and complete chloroplast membrane, which will greatly help to improve photosynthetic capacity and energy efficiency of ear leaf in maize parental lines. It is concluded that grain yield increase in modern maize parental lines is mainly attributed to the improved chloroplast structure and more light energy catched for the photochemical reaction, thus having a better stay-green characteristic and stronger photosynthetic capacity after anthesis. Our direct physiological evaluation of these inbred lines provides important information for the further development of promising maize cultivars.

Improving the yield of maize grain per unit area is needed to meet the growing demand for it in China, where the availability of fertile land is very limited. Modified fertilization management and planting density are efficient methods for increasing crop yield. Field experiments were designed to investigate the influence of modified fertilization management and planting density on grain yield and nitrogen use efficiency of the popular maize variety Zhengdan 958, in four treatments including local farmer’s practice (FP), high-yielding and high efficiency cultivation (HH), super high-yielding cultivation (SH), and the control (CK). Trials were conducted in three locations of the Huang-Huai-Hai Plain in northern China. Compared with FP, SH was clearly able to promote N absorption and dry matter accumulation in post-anthesis, and achieve high yield and N use efficiency by increasing planting density and postponing the supplementary application of fertilizers. However, with an increase in planting density, the demand of N increased along with grain yield. Due to the input of too much N fertilizer, the efficiency of N use in SH was low. Applying less total N, ameliorating cultivation and cropping management practices should be considered as priority strategies to augment production potential and finally achieve synchronization between high yield and high N efficiency in fertile soils. However, in situations where soil fertility is low, achieving high yield and high N use efficiency in maize will likely depend on increased planting density and appropriate application of supplementary fertilizers postpone to the grain-filling stage.

Proper application of nitrogen (N) fertilizers and irrigation management are important production practices that can reduce nitrate leaching into groundwater and improve the N use efficiency (NUE). A lysimeter/rain shelter facility was used to study effects of the rate of N fertilization, type of N fertilizer, and irrigation level on key aspects of winter wheat production over three growing seasons (response variables were nitrate transport, N leaching, and NUE). Results indicated that nitrate concentration in the soil profile and N leaching increased with the rate of N fertilization. At the end of the third season, nitrate concentration in the top 0–75 cm layer of soil was higher with manure treatment while urea treatments resulted in higher concentrations in the 100–200 cm layer. With normal irrigation, 3.4 to 15.3% of N from applied fertilizer was leached from the soil, yet no leaching occurred under a stress irrigation treatment. The manure treatment experienced less N leaching than the urea treatment in all cases except for the 180 kg N ha-1 rate in 2011–2012 (season 3). In terms of grain yield (GY), dry matter (DM) or NUE parameters, values for the manure treatment were lower than for the urea treatment in 2009–2010 (season 1), yet were otherwise higher for urea treatment in season 3. GY and crop nitrogen uptake (NU) were elevated when the rate of N fertilizer increased, while the NUE decreased; GY, DM, and NU increased with the amount of irrigation. Data indicated that reduced rates of N fertilization combined with increased manure application and proper irrigation management can lower nitrate levels in the subsoil and reduce potential N leaching into groundwater.

A pot experiment was conducted to investigate the effect of different arsenic (As) levels on maize (Zea mays L.) growth and As accumulation and species in different parts of maize plants, as a guideline for production of maize in As-polluted areas with the objective of preventing As from entering the food chain, and improving understanding of the mechanisms of effect of As on plant. Zhengdan 958 was grown at five As levels added to soil (0, 12.5, 25, 50, and 100 mg kg-1 As). As concentration in maize tissues increased in the order of grain<stalk<leaf<<root. The As concentration in maize grain exceeded the maximum permissible concentration of 0.7 mg kg-1 in China at levels of 50 and 100 mg kg-1. As species were presented in root, stalk, and grain, but organic As was the major As species identified in the grain. Maize plants were able to reduce arsenate to arsenite. Low As levels of 12.5 and 25 mg kg-1 improved maize growth and grain nutrition quality, while high levels of As 50 or 100 mg kg-1 inhibited them. Yield reduction at high As levels resulted mainly from reduced ear length, kernel number per row, and kernel weight.