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Rational nitrogen (N) application can enhance yield and improve grain eating quality in rice. However, excessive N input can deteriorate grain eating quality and aggravate environmental pollution, while reduced N application (RN) decreases rice yield. Reduced N application with dense planting (RNDP) is recommended for maintaining rice yield and improving N use efficiency. However, the effects of RNDP on the rice grain eating quality and starch structure and properties remain unclear. A two-year field experiment was conducted to investigate the effects of RNDP on the rice yield, grain eating quality, and starch structure and properties. Compared to conventional N treatment, RN decreased significantly the rice yield, while RNDP achieved a comparable grain yield. Both the RN and RNDP treatments improved significantly the rice eating quality. The high eating quality of RNDP was attributed to increased gel consistency, pasting viscosity, and stickiness after cooking as well as decreased protein content. A further analysis of starch structure and properties revealed that RNDP decreased the relative crystallinity, lamellar intensity, gelatinization enthalpy, and retrogradation enthalpy of starch. Therefore, RNDP achieved a stable rice yield and enhanced rice eating quality. These findings provide valuable insights into obtaining optimal quality and consistent yield in rice production under reduced N conditions. [ABSTRACT FROM AUTHOR]

Summary: Increased planting densities boost crop yields. A compact plant architecture facilitates dense planting. However, the mechanisms regulating compact plant architecture in cucurbits remain unclear. In this study, we identified a cucumber (Cucumis sativus) compact plant architecture (cpa1) mutant from an ethyl methane sulfonate (EMS)‐mutagenized library that exhibited distinctive phenotypic traits, including reduced leaf petiole angle and leaf size. The candidate mutation causes a premature stop codon in CsaV3_1G036420, which shares similarity to Arabidopsis HOOKLESS 1 (HLS1) encoding putative histone N‐acetyltransferase (HAT) protein and was named CsHLS1. Consistent with the mutant phenotype, CsHLS1 was predominantly expressed in leaf petiole bases and leaves. Constitutive overexpressing CsHLS1 in cpa1 restored the wild‐type plant architecture. Knockout of CsHLS1 resulted in reduces leaf petiole angle and leaf size and as well as decreased acetylation levels. Furthermore, CsHLS1 directly interacted with CsSCL28 and negatively regulated compact plant architecture in cucumber. Importantly, CsHLS1 knockout increased the photosynthesis rate and leaf nitrogen in cucumbers, thereby maintaining cucumber yield at normal density. Overall, our research provides valuable genetic breeding resource and gene target for creating a compact plant architecture for dense cucumber planting. [ABSTRACT FROM AUTHOR]

Aiming at the production and ecological problems of the lack of water resources and excessive chemical nitrogen fertilizer input in arid oasis irrigation areas, the effect of increased planting density to compensate for the loss of maize yield caused by reducing water and nitrogen inputs was analyzed under reduced water and nitrogen inputs, which could provide theoretical and technical support for the efficient production of maize with water and nitrogen reduction. Based on a split-plot field experiment conducted in 2016, the main plot was divided into two irrigation quotas: reduced irrigation by 20% (W1, 3240 m³ hm-2) and traditional irrigation (W2, 4050 m³ hm-2), and the split-plot was divided into two nitrogen application rates: reduced nitrogen (N1, 270 kg hm-2) by 25% and traditional nitrogen (N2, 360 kg hm-2) were applied, and the sub-split plot was divided into three maize densities: traditional planting density (D1, 75,000 hm-2 plants), increased density by 30% (D2, 97, 500 hm-2 plants) and increased density by 60% (D3, 120,000 hm-2 plants). We measured grain yield and biological yield of maize in 2020 and 2021, analyzed the characteristics of dry matter accumulation, distribution, and transport characteristics, quantified the yield composition factors, and clarified the compensation effect and mechanism of densification on maize yield with water and nitrogen reduction. The study showed that water and nitrogen reduction inputs decreased the grain yield and biological yield in maize, but the increased density by 30% can compensate for the loss of yield due to reducing water and nitrogen inputs and improve maize yield under reduced water while maintaining traditional nitrogen. The grain yield and biological yield of W1N1D1 (reduced water and nitrogen and traditional density) was 9.1%-15.0% and 10.0%-11.0% lower than W2N2D1 (comparison: traditional irrigation, traditional nitrogen application, and traditional density), but there was no significant difference in W1N1D2 (reduced irrigation, reduced nitrogen, and increased density by 30%) compared with W2N2D1. Compared with W2N2D1, W1N2D2 (reduced irrigation, traditional nitrogen, and increased density by 30%) increased grain yield and biological yield by 12.9%--15.4% and 6.4%-12.0%, respectively. Increased density by 30% compensated for the negative effect of water and nitrogen reduction mainly attributed to improving spike number of W1N1D2, which further increased dry matter accumulation from the early-filling stage to the maturity stage in maize, population growth rate and dry matter remobilization at pre-anthesis from seeding stage to the flare opening stage. Increasing spike number of W1N2D2 improved dry matter accumulation and population growth rate, promoted dry matter distribution in the ear, and increased dry matter remobilization. In addition, the dry matter remobilization efficiency and contribution of dry matter remobilization to grain at pre-anthesis were the main reasons for increasing maize yield with the increased density by 30% under water and nitrogen reduction inputs. Therefore, increasing density by 30% was a feasible measure for simultaneous reduction of water and nitrogen in oasis irrigation area to stabilize and increase maize yield. [ABSTRACT FROM AUTHOR]

Rational nitrogen (N) application can enhance yield and improve grain eating quality in rice. However, excessive N input can deteriorate grain eating quality and aggravate environmental pollution, while reduced N application (RN) decreases rice yield. Reduced N application with dense planting (RNDP) is recommended for maintaining rice yield and improving N use efficiency. However, the effects of RNDP on the rice grain eating quality and starch structure and properties remain unclear. A two-year field experiment was conducted to investigate the effects of RNDP on the rice yield, grain eating quality, and starch structure and properties. Compared to conventional N treatment, RN decreased significantly the rice yield, while RNDP achieved a comparable grain yield. Both the RN and RNDP treatments improved significantly the rice eating quality. The high eating quality of RNDP was attributed to increased gel consistency, pasting viscosity, and stickiness after cooking as well as decreased protein content. A further analysis of starch structure and properties revealed that RNDP decreased the relative crystallinity, lamellar intensity, gelatinization enthalpy, and retrogradation enthalpy of starch. Therefore, RNDP achieved a stable rice yield and enhanced rice eating quality. These findings provide valuable insights into obtaining optimal quality and consistent yield in rice production under reduced N conditions.

High-density planting is a vital cultivation measure to improve crop yield. In the semi-arid region, insufficient precipitation and high variability are the primary factors that restrict agricultural development. Matching planting density and fertilizer application with precipitation is a promising technical strategy to ensure yield stability and enhance nitrogen (N) use efficiency (NUE). To achieve this objective, we conducted a continuous field experiment in the Loess Plateau region of Northwest China between 2015 and 2020. Under conventional (CF) and reduced fertilization (RF, 20 % CF) conditions, we investigated the response characteristics of dry matter accumulation, yield, yield components, NUE, N surplus, and net income of maize as the density increased from 5.25 (D1) to 6.75 (D2), 8.25 (D3), and 9.75 (D4) × 104 plants ha−1. The results indicated that reduced fertilizer application led to a decrease in grain yield by 6.2–8.7 %, whereas increasing the density by at least 1.50 × 104 plants ha−1 (D2) could compensate for the yield reduction caused by reduced fertilization (N 55 + P 2 O 5 27 kg ha−1) in normal and wet years. The compensatory effect initially increased and then decreased as the density increased, with the highest yield observed at planting density D3. By increasing the rapid growth rate of maize (6.3–17.1 %) and extending the rapid growth duration (0.9–2.5 days) through high planting density, reduced fertilization combined with high-density planting (RF·D3) significantly increased the cumulative yield, yield stability, net income, and NUE was by 9.4 %, 18.9 %, 10.6 %, and 37.0 %, respectively, over six years, compared with CF·D1 treatment. Additionally, the N surplus was reduced by 44.6 %. In conclusion, using reduced fertilization with high planting density measures can achieve yield stability and sustainable maize production in semi-arid areas. [Display omitted] • High density planting saved fertilizer without yield reduction. • Rainfall and its distribution affected the variability of planting density. • Increasing planting density in normal and wet years had compensatory effects. [ABSTRACT FROM AUTHOR]

Planting maize (Zea mays L.) reasonably densely and adding amounts of appropriate nitrogen fertilizer are essential measures to improve the efficiency of maize yield and nitrogen use. In this study, two planting densities of 7.5 × 104 plants ha−1 and 12.0 × 104 plants ha−1 were established with the maize varieties DengHai 618 (DH618) and XianYu 335 (XY335). Simultaneously, 18 levels of nitrogen application were established, including a lack of nitrogen (N0) and increments of 45 kg ha−1 nitrogen up to 765 (N765) kg ha−1. The variables studied included the effects of the rate of nitrogen application on the characteristics of dry matter accumulation and the yield under drip irrigation, and they were integrated into water–fertilizer integration. The results indicated that the yield, harvest index, and dry matter accumulation of maize displayed a trend of increasing and then tending to be flat as the amount of nitrogen applied increased. The use of linear plus platform equation fitting indicated that the change in yield with nitrogen administered had the lowest turning point at N = 279 and N = 319, respectively. The next parameter that was measured was the harvest index. When highly dense maize was grown before silking, the rate of nitrogen applied was more obviously impacted by the accumulation of dry matter. The harvest index contributed 22.9–27.2% of the yield, and the total dry matter accumulation before and after silking contributed more than 70% of the production. Increasing the amount of nitrogen fertilizer is beneficial to prolonging the dry matter accumulation time and increasing the dry matter accumulation rate. The accumulation amount of dry matter was positively correlated with accumulation time and rate, and the correlation between dry matter and accumulation rate was greater. In conclusion, applying the right amount of nitrogen can dramatically increase the harvest index, accumulation of materials, and yield, with dry matter accumulation having the greatest influence on yield. The creation of dry matter is influenced by the time and rate of its accumulation, with its rate serving as the primary controlling factor. [ABSTRACT FROM AUTHOR]

Tillage is an important management tool for tackling and promoting water conservation and improving crop yield. As one of the important nutrients in plant growth, K is involved in important processes such as osmoregulation, photosynthesis and metabolite transport, and plays a particularly critical role in improving crop yield and quality. In the long-term positioning platform of the tillage method, a 2-yr field experiment was conducted in 2019-2020 in maize (Zea mays L.) Three tillage methods: conventional tillage (CT), subsoil tillage (ST), and no-tillage (NT) and two planting densities 6x104 (D1) and 9x104 plants ha-1 (D2) were set up in the experiment. The results showed that yield and K translocation efficiency (KTE) were significantly higher in NT than in CT at D1 (by 4.7% and 12.2%) and D2 (by 14.0% and 13.9%), respectively. At maturity stage in 2019, population DM accumulation after silking (DMA) was significantly higher in NT (by 11.0% and 16.9%) than in CT at D1 and D2. Correlation analysis revealed that yield was significantly positive correlated with ears (r = 0.57***) and DMA (r = 0.64***). Potassium translocation and K harvest index were positively correlated with KTE. Under spring drought year, the long-term no-tillage had a significant yield increase, mainly through the increase in 1000-kernel weight. The increase in K efficiency was mainly through the influence of DM accumulation and distribution, and K accumulation in grain. [ABSTRACT FROM AUTHOR]

The selection of high-yielding, short-duration rice cultivars is essential for the double-rice cropping system. High hill density could be achieved with less labor under machine transplanted conditions. Therefore, dense planting is more practical for machine-transplanted rice. While few studies have been conducted to certify the feasibility of short-duration cultivar combined with dense planting in machine transplanted conditions. The current study was executed to determine the effects of dense planting on yield attributes and grain yield of short-duration cultivars under mechanically transplanted conditions. A field experiment comprises two treatments—i.e., the short-duration cultivar Lingliangyou104 cultivated at a high planting density (SDH) and the long-duration Taiyou390 cultivar cultivated at a low planting density (LDL)—were conducted in the 2018 and 2019 late seasons. The results showed that the SDH exhibited 17% and 19% higher panicle number in a unit, 26% and 24% higher spikelet filling, 8% and 8% higher grain weight, 21% and 11% higher harvest index, and consequently 12% and 4% higher grain yield and 13 and 15 days shortened growth duration compared to the LDL in the 2018 and 2019, respectively. The data revealed that the difference in grain yield between the SDH and LDL was mainly due to the higher harvest index and reasonable dry matter distribution of the SDH, which was conducive to improving yield components and increasing rice grain yield. As a result, short-duration rice cultivars combined with dense planting is a feasible strategy for improving the grain yield of mechanically transplanted late rice. [ABSTRACT FROM AUTHOR]

To ensure enough crop production of limited land area is important to food security. The key to solve this issue is to increase yield per unit area. Dense planting is an effective agronomic management practice to increase yield per unit area, photosynthetic rate would not be decreased or even improved by increasing planting density moderately, and then enhancing the yield per unit area. It is a key research focus on revealing the mechanism of photosynthetic physiology for improving yield per unit area by dense planting condition of maize. Dense planting would lead to change photosynthetic characteristics, so controlling the physiological factors that restricts photosynthesis is essential for increasing yield. Tap the photosynthetic physiologic potential for maize condition is physiological basis to ensure yield, which plays an important role in addressing food security issues. Therefore, this review focuses on the changes of the research methods and ideas in photosynthetic physiology, and the research status of the photosynthetic physiological response of maize adapted to dense planting and related agronomic regulation pathways at home and abroad, based on previous research results, so as to provide the theoretical and technical methods basis for photosynthetic physiology research. Based on the development trend of modern technology, it is believed that tapping photosynthetic potential and narrowing the gap between photosynthetic potential and actual photosynthetic efficiency are still the main goals of maize dense planting research by traditional research methods combined with molecular biology techniques in the future. In further study, research emphasis should be to investigate the responses of differential expression of photosynthetic physiological function genes to cultivation measures, clarifying the relationship and interaction between agronomic management practice and information expression of photosynthetic-related genes in densely planted maize, enhancing photosynthetic potential for maize via agronomic management practice and molecular biology technology, in order to provide photosynthetic physiological theory and practice to support for maize dense planting. [ABSTRACT FROM AUTHOR]

Rice is one of the important staple food crops in China. Precision agricultural management can be critical to the high rice yield for national food and ecological security. Fortunately, the controlled-release fertilizer is a novel kind of nutrient-efficient and environment-friendly fertilizer. Better synchronizing the nitrogen (N) release and crop uptake can be utilized to promote the crop yield and nitrogen use efficiency (NUE), while reducing the reactive N losses. At the same time, moderate-density planting can be used to enhance the nutrient uptake by the rice plants, leading to reduce the nutrient losses and fertilizer application rate. This study aims to determine the effects of the blends of controlled-release and conventional N fertilizers combined with the dense planting on the rice yield, N uptake, economic benefits, and ammonia (NH3) volatilization. A paddy field experiment was also conducted to plant with the rice cultivar of Yangxianyou 418. Five treatments of N fertilizer management were established, including no N fertilizer (CK), conventional N fertilizer (FFP), optimized N fertilizer (OPT), blends of controlled-release and conventional N fertilizers (CRBF), as well as the blends of controlled-release and conventional N fertilizers combined with dense planting (CRFDP). Among them, the total N was applied all at once as the basal fertilization in the CRBF and CRFDP treatments. A comparison analysis was made on the rice yield, yield components, N uptake, NUE, economic benefits, and NH3 volatilization under different treatments. The highest numbers of effective panicles per plant and effective grains per panicle of rice plants were observed under the CRFDP, which were significantly (P<0.05) higher than those under the FFP by 26.1% and 18.7%, respectively. The CRFDP treatment significantly (P<0.05) increased the rice yield by 33.3%, compared with the FFP. Specifically, the N recovery efficiency (NRE), N agronomic efficiency (NAE), N partial factor productivity (NPFP), and significantly increased by 160%, 22.8 kg/kg, and 16.27 kg/kg, respectively, under the CRFDP, compared with the FFP. The NRE of CRFDP treatment was significantly (P<0.05) higher than that of CRBF by 10%, while there was no significant difference in the NAE, NPFP, and NPE. The optimized N fertilization treatments (OPT, CRBF, and CRFDP) increased the net economic benefits of rice by 3 328-8 968 yuan/hm² with a 20% reduction in N application rate, compared with the FFP treatment. Besides, the CRFDP treatment presented the highest output value and net economic benefits among different optimized N fertilization treatments. The application of N fertilizer significantly increased the ammonium-nitrogen concentration in the surface water and soil urease activity in the paddy field during the rice growing season. The episodic and cumulative NH3 volatilization significantly (P<0.05) decreased by 62.5% and 46.3%, respectively, under the CRFDP, compared with the FFP. In conclusion, the blends of controlled-release and conventional N fertilizers combined with the dense planting can be expected to concurrently benefit the yield, NUE, and the reduced NH3 loss in the rice production system [ABSTRACT FROM AUTHOR]

Dense planting could be a feasible method for reducing nitrogen (N) application rates without compromising rice grain yield in northeast and central China. It is still unclear whether reduced N application with dense planting (RNDP) can achieve higher rice yield and N use efficiency (NUE) in Jiangsu, east China. Three japonica inbred rice (JI) and three indica hybrid rice (IH) cultivars were grown in a field experiment. Their grain yield, NUE, and related traits were compared under two cultivation treatments: conventional high-yielding practice (CHYP) and RNDP. JI showed similar yields under the two treatments, while IH showed lower yield under RNDP than under CHYP, and the partial factor productivity of N and N use efficiency for grain yield increased (P

Under the current rice cropping system, excessive nitrogen application has become a major issue that needs to be changed, and nitrogen reduction has become a hot research topic in recent years. The use of optimum planting density is becoming a common agronomic management system in addition to nitrogen reduction, especially under double cropping rice systems. In this paper, changes in rice yield, nitrogen-use efficiency (NUE) and net N mineralization under dense planting with a reduced nitrogen rate (DPRN) were studied. By comparing DPRN with high-nitrogen sparse planting (SPHN), we found that the population tiller number (tiller number per unit area) increased by 9–27% under DPRN cultivation. Nitrogen accumulation under DPRN treatment of double-cropped rice was basically stable. NUE under DPRN was significantly higher by 1.3–22.7% compared to SPHN. The partial factor productivity of applied N (PFPN) was significantly higher than that of SPHN, with an increase of 4.3–22.8%. The net N mineralized of double-cropped rice under DPRN increased at different stages, and the increase in late-season rice (LSR) was greater than that of early-season rice (ESR). The highest net N mineralized in double cropping rice at different stages was found in the dense planting treatment (DP) and N2 (120 kg N h−1). In conclusion, DPRN cultivation of double-cropped rice could be accepted as a proper management strategy for reducing nitrogen input, improving NUE and promoting soil nitrogen mineralization under given conditions. [ABSTRACT FROM AUTHOR]

Maize (Zea mays L.) is usually planted at high density, so most of its leaves grow in low light. Certain morphological and physiological traits improve leaf photosynthetic capacity under low light, but how light absorption, transmission, and transport respond at the proteomic level remains unclear. Here, we used tandem mass tag (TMT) quantitative proteomics to investigate maize photosynthesis-related proteins under low light due to dense planting, finding increased levels of proteins related to photosystem II (PSII), PSI, and cytochrome b6f. These increases likely promote intersystem electron transport and increased PSI end electron acceptor abundance. OJIP transient curves revealed increases in some fluorescence parameters under low light: quantum yield for electron transport (φEo), probability that an electron moves beyond the primary acceptor QA− (ψo), efficiency/probability of electron transfer from intersystem electron carriers to reduction end electron acceptors at the PSI acceptor side (δRo), quantum yield for reduction of end electron acceptors at the PSI acceptor side (φRo), and overall performance up to the PSI end electron acceptors (PItotal). Thus, densely planted maize shows elevated light utilization through increased electron transport efficiency, which promotes coordination between PSII and PSI, as reflected by higher apparent quantum efficiency (AQE), lower light compensation point (LCP), and lower dark respiration rate (Rd). [ABSTRACT FROM AUTHOR]

Summary: High‐density planting is an effective measure for increasing crop yield per unit land area. Leaf angle (LA) is a key trait of plant architecture and a target for genetic improvement of crops. Upright leaves allow better light capture in canopy under high‐density planting, thus enhancing photosynthesis efficiency, ventilation and stress resistance, and ultimately higher grain yield. Here, we summarized the latest progress on the cellular and molecular mechanisms regulating LA formation in rice and maize. We suggest several standing out questions for future studies and then propose some promising strategies to manipulate LA for breeding of cereal crops tailored for high‐density planting. [ABSTRACT FROM AUTHOR]

The mode of sparse planting with high N(nitrogen) application in Northeast China is not conducive to high and stable yields nor efficient use of resources. This study investigated if dense planting with less N fertilization in rice could improve nitrogen use efficiency (NUE) and increase yield in Northeast China. we conducted a field experiment using Jijing 88 and Tonghe 99 as planting material and setting three cropping modes of dense planting with less N (T1: 30 cm × 13.3 cm, 200 kg·ha−1; T2: 25 cm × 13.3 cm, 175 kg·ha−1; T3: 25 cm × 10 cm, 150 kg·ha−1) and a local conventional cropping pattern (CK: 30 cm × 16.5 cm, 225 kg·ha−1). The results showed that, when compared to CK, dense planting with less N application (T1, T2) increased the maximum tiller number, above-ground biomass and obtained higher panicle number per m−2 and grain filling rate. The maximum yields of Jijing 88 occurred with T1, which increased by 1.29% on average compared to CK; The maximum yields of Tonghe 99 occurred with T2, which increased by 3.50% on average compared to CK. The T1and T2 increased apparent recovery efficiency of nitrogen fertilizer (REN), agronomic nitrogen use efficiency (AEN), internal nitrogen use efficiency (IEN) compared to CK. Together, reducing N rate from 225 kg·ha−1 (CK) to 175 kg·ha−1 (T2) could obtained resulted generally equal or higher grain yield and higher NUE with increasing transplanting density from 30 cm × 16.5 cm (CK) to 25 cm × 13.3 cm (T2), and dense planting is a feasible strategy to reduce N input in Northeast China. [ABSTRACT FROM AUTHOR]

The high nitrogen (N) application rates typically used in Chinese cropping systems have led to diminishing returns for yields and have also imposed substantial environmental costs. Here, we estimate that the annual N loss from rice production in China reached approximately 2.6×109 kg from 2011 to 2015, and we demonstrate that adoption of the mechanically dense transplanting technique by producers is an effective method to reduce N loss from rice cropping systems without suffering a yield penalty.

The selection of high-yielding, short-duration rice cultivars is essential for the double-rice cropping system. High hill density could be achieved with less labor under machine transplanted conditions. Therefore, dense planting is more practical for machine-transplanted rice. While few studies have been conducted to certify the feasibility of short-duration cultivar combined with dense planting in machine transplanted conditions. The current study was executed to determine the effects of dense planting on yield attributes and grain yield of short-duration cultivars under mechanically transplanted conditions. A field experiment comprises two treatments—i.e., the short-duration cultivar Lingliangyou104 cultivated at a high planting density (SDH) and the long-duration Taiyou390 cultivar cultivated at a low planting density (LDL)—were conducted in the 2018 and 2019 late seasons. The results showed that the SDH exhibited 17% and 19% higher panicle number in a unit, 26% and 24% higher spikelet filling, 8% and 8% higher grain weight, 21% and 11% higher harvest index, and consequently 12% and 4% higher grain yield and 13 and 15 days shortened growth duration compared to the LDL in the 2018 and 2019, respectively. The data revealed that the difference in grain yield between the SDH and LDL was mainly due to the higher harvest index and reasonable dry matter distribution of the SDH, which was conducive to improving yield components and increasing rice grain yield. As a result, short-duration rice cultivars combined with dense planting is a feasible strategy for improving the grain yield of mechanically transplanted late rice.

Under the current rice cropping system, excessive nitrogen application has become a major issue that needs to be changed, and nitrogen reduction has become a hot research topic in recent years. The use of optimum planting density is becoming a common agronomic management system in addition to nitrogen reduction, especially under double cropping rice systems. In this paper, changes in rice yield, nitrogen-use efficiency (NUE) and net N mineralization under dense planting with a reduced nitrogen rate (DPRN) were studied. By comparing DPRN with high-nitrogen sparse planting (SPHN), we found that the population tiller number (tiller number per unit area) increased by 9–27% under DPRN cultivation. Nitrogen accumulation under DPRN treatment of double-cropped rice was basically stable. NUE under DPRN was significantly higher by 1.3–22.7% compared to SPHN. The partial factor productivity of applied N (PFPN) was significantly higher than that of SPHN, with an increase of 4.3–22.8%. The net N mineralized of double-cropped rice under DPRN increased at different stages, and the increase in late-season rice (LSR) was greater than that of early-season rice (ESR). The highest net N mineralized in double cropping rice at different stages was found in the dense planting treatment (DP) and N2 (120 kg N h−1). In conclusion, DPRN cultivation of double-cropped rice could be accepted as a proper management strategy for reducing nitrogen input, improving NUE and promoting soil nitrogen mineralization under given conditions.

Maize (Zea mays L.) is usually planted at high density, so most of its leaves grow in low light. Certain morphological and physiological traits improve leaf photosynthetic capacity under low light, but how light absorption, transmission, and transport respond at the proteomic level remains unclear. Here, we used tandem mass tag (TMT) quantitative proteomics to investigate maize photosynthesis-related proteins under low light due to dense planting, finding increased levels of proteins related to photosystem II (PSII), PSI, and cytochrome b6f. These increases likely promote intersystem electron transport and increased PSI end electron acceptor abundance. OJIP transient curves revealed increases in some fluorescence parameters under low light: quantum yield for electron transport (φEo), probability that an electron moves beyond the primary acceptor QA− (ψo), efficiency/probability of electron transfer from intersystem electron carriers to reduction end electron acceptors at the PSI acceptor side (δRo), quantum yield for reduction of end electron acceptors at the PSI acceptor side (φRo), and overall performance up to the PSI end electron acceptors (PItotal). Thus, densely planted maize shows elevated light utilization through increased electron transport efficiency, which promotes coordination between PSII and PSI, as reflected by higher apparent quantum efficiency (AQE), lower light compensation point (LCP), and lower dark respiration rate (Rd).

Keywords: maize; dense planting; lodging resistance; D1; ZmSPL12 EN maize dense planting lodging resistance D1 ZmSPL12 622 624 3 04/11/22 20220401 NES 220401 Introduction of the semi-dwarf genes ( I sd1 i in rice, I RhtB1b i and I RhtD1b i in wheat) has drastically increased lodging resistance and grain yields in these two important crops since the 1960s, resulting in the so called "Green Revolution" (Hedden, 2003). Together, our results demonstrate that I ZmSPL12 i could mimic the function of "Green Revolution" genes to confer reduced plant height and increased lodging resistance, thus facilitating high-density planting and increased yield in maize. [Extracted from the article]

Abstract Yield-improving and water-saving techniques assume great importance in the cultivation of banana plants under semiarid regions, prone to greater climate variability. The objective of this study was to evaluate yield and water-use efficiency (WUE) response of ‘Prata-Anã’ banana plants to combinations of plant densities and irrigation levels: three irrigation levels, 50, 75 and 100% crop evapotranspiration (ETc), and four plant densities, 1,666 (3.0 x 2.0 m), 2,083 (3.0 x 1.6 m), 2,666 (3.0 x 1.25 m) and 3,333 (3.0 x 1.0) plants ha-1, evaluated in two production cycles. The treatments were laid out in a randomized block design with four replicates. Increasing plant density up to 3,333 plants ha-1 induced reductions in number of leaves at harvest and some yield components; also, longer cycles, and increased yields were observed while maintaining fruit marketable size, regardless of the irrigation level used. Using an irrigation level at 50%ETc and a plant density of 3,333 plants ha-1 led to an increase in WUE of 313.92% in the first cycle and 295.27% in the second cycle compared with 1,666 plants ha-1 irrigated at 100% ETc. Higher yields and WUE can be achieved by using a plant population density of 3,333 plants ha-1 and irrigation levels below 100%ETc.

Determining the water productivity of maize is of great significance for ensuring food security and coping with climate change. In 2018 and 2019, we conducted field trials in arid areas (Changji), semi-arid areas (Qitai) and semi-humid areas (Xinyuan). The hybrid XY335 was selected for the experiment, the planting density was 12.0 × 104 plants ha−1, and five irrigation amounts were set. The results showed that yield, biomass, and transpiration varied substantially and significantly between experimental sites, irrigation and years. Likewise, water use efficiency (WUE) for both biomass (WUEB) and yield (WUEY) were affected by these factors, including a significant interaction. Normalized water productivity (WP*) of maize increased significantly with an increase in irrigation. The WP* for film mulched drip irrigation maize was 37.81 g m−2 d−1; it was varied significantly between sites and irrigation or their interaction. We conclude that WP* differs from the conventional parameter for water productivity but is a useful parameter for assessing the attainable rate of film-mulched drip irrigation maize growth and yield in arid areas, semi-arid areas and semi-humid areas. The parametric AquaCrop model was not accurate in simulating soil water under film mulching. However, it was suitable for the prediction of canopy coverage (CC) for most irrigation treatments.

A two-year field experiment was conducted to evaluate the effects of plant density on tassel and ear differentiation, anthesis-silking interval (ASI), and grain yield formation of two types of modern maize hybrids (Zhongdan 909 (ZD909) as tolerant hybrid to crowding stress, Jidan 209 (JD209) and Neidan 4 (ND4) as intolerant hybrids to crowding stress) in Northeast China. Plant densities of 4.50×104 (D1), 6.75×104 (D2), 9.00×104 (D3), 11.25×104 (D4), and 13.50×104 (D5) plants ha–1 had no significant effects on initial time of tassel and ear differentiation of maize. Instead, higher plant density delayed the tassel and ear development during floret differentiation and sexual organ formation stage, subsequently resulting in ASI increments at the rate of 1.2–2.9 days on average for ZD909 in 2013–2014, 0.7–4.2 days for JD209 in 2013, and 0.5–3.7 days for ND4 in 2014, respectively, under the treatments of D2, D3, D4, and D5 compared to that under the D1 treatment. Total florets, silking florets, and silking rates of ear showed slightly decrease trends with the plant density increasing, whereas the normal kernels seriously decreased at the rate of 11.0–44.9% on average for ZD909 in 2013–2014, 2.0–32.6% for JD209 in 2013, and 9.7–28.3% for ND4 in 2014 with the plant density increased compared to that under the D1 treatment due to increased florets abortive rates. It was also observed that 100-kernel weight of ZD909 showed less decrease trend compared that of JD209 and ND4 along with the plant densities increase. As a consequence, ZD909 gained its highest grain yield by 13.7 t ha–1 on average at the plant density of 9.00×104 plants ha–1, whereas JD209 and ND4 reached their highest grain yields by 11.7 and 10.2 t ha–1 at the plant density of 6.75×104 plants ha–1, respectively. Our experiment demonstrated that hybrids with lower ASI, higher kernel number potential per ear, and relative constant 100-kernel weight (e.g., ZD909) could achieve higher yield under dense planting in high latitude area (e.g., Northeast China).

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Copyright of Revista Brasileira de Engenharia Agricola e Ambiental - Agriambi is the property of Revista Brasileira de Engenharia Agricola e Ambiental and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• The effect of dense planting with reducing nitrogen rate (DPRN) on hybrid rice were determined. • DPRN increased grain yield in two hybrid rice varieties across two light conditions. • DPRN increased nitrogen use efficiency in two hybrid rice varieties across two light conditions. Dense planting with reducing nitrogen rate (DPRN) is a sustainable strategy to improve rice yield and nitrogen (N) use efficiency. Nevertheless, the feasibility of such strategy under low light stress condition has not been examined in detail. Two field experiments and a micro-plot experiment were conducted to evaluate the performance of DPRN and sparse planting with high N rate (SPHN) under two light conditions (L 0 , natural light intensity and L 1 , 30% of L 0) with two contrasting hybrid rice varieties (Yliangyou 1 and Luoyou 9348) in 2014 and 2015. In field experiments, L 1 resulted in sharp decline in grain filling, 1000-grain weight, biomass, harvest index, N uptake, N use efficiency for grain production and partial factor productivity of applied N fertilizer, and consequently 41.2–53.4% grain yield loss for two varieties in comparison with L 0. Interestingly, 8.6–13.5% higher grain yield, and better performance of yield components and N use efficiency were observed from DPRN than SPHN across two light conditions. In micro-plot experiment, responses of grain dry weight and yield-attributing traits to light intensity and crop managements were similar to those in field experiments. No difference was observed in N uptake from fertilizer, N recovery rate, N retention rate and N loss rate between L 0 and L 1 , while DPRN increased N recovery rate by 14.8% and N retention rate by 35.1%, and consequently decreased N loss rate by 29.4% across two light conditions compared with SPHN. The differences in responses of grain yield and related parameters to low light stress (L 1) between the two cultivars were small. These results suggest that DPRN is also feasible to increase grain yield and N use efficiency for hybrid rice varieties grown under two light conditions. [ABSTRACT FROM AUTHOR]

Copyright of Xinjiang Agricultural Sciences is the property of Xinjiang Agricultural Sciences Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Agronomica Sinica is the property of Crop Science Society of China and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Enhancing the basal internode mechanical strength by improving the canopy light distribution of dense planting maize to reduce the lodging rate is important for establishing a high-yielding and stable population. A three-year field experiment was carried out at three densities treatments (5.25 × 104, 6.75 × 104 and 8.25 × 104 plants hm−2) × four nitrogen fertilizer treatments (0, 120, 180 and 240 kg hm−2) to study canopy light distribution and stalk lodging resistance characteristics. Results showed that grain yield was increased 3.31–14.68% under 6.75 × 104 plants hm−2 treatment compared to 5.25 × 104 plants hm−2. Meanwhile, plant morphology was altered with the increasing of planting density, light interception rate at lower-middle canopy position (0–150 cm) was decreased 15.10%, thus the mechanical strength of the basal internodes was reduced, and the lodging rate was increased 4.66% points. The formation of maize stalk lodging resistance and grain yield was promoted by the nitrogen fertilizer application. The N 180 treatment improved mechanical strength by enhancing canopy light distribution and optimizing internode quality, lodging rate was decreased 6.31–17.22% compared to the N 240 treatment while only a 0.54–7.54% reduction in grain yield, finally. Analysis the relationship between characteristic factors and mechanical strength, we found that internode plumpness (explained the 85.6% percentage of variability) was the key factor affecting basal internode mechanical strength. Our results will assist breeders in breeding lodging-resistant hybrids and agronomists improving field management practices for low lodging rate and high yield, and will be equally illuminating for other maize-producing regions. • The lower-middle canopy position light interception rate affected internode mechanical strength. • Nitrogen fertilizer management optimized canopy light distribution affecting stalk lodging resistance. • Internode plumpness was the key factor affecting internode mechanical strength. [ABSTRACT FROM AUTHOR]

Copyright of Acta Agronomica Sinica is the property of Crop Science Society of China and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

At present, maize yields as high as 15.0 Mg ha−1 can be achieved under fully irrigated conditions in China. However, due to water restrictions, exploring appropriate water-saving irrigation methods is of great significance. Here, we sought to test the ability of several irrigation regimes to maintain high grain yield while increasing water productivity (WP c). Two water-saving irrigation methods, deficit irrigation (DI) and regulated deficit irrigation (RDI), were optimized based on changes in maize water consumption and soil water content over the growing season. The experiments were carried out in one of China's primary spring maize-producing areas (Qitai, Xinjiang) in 2019 and 2020, with mulched drip irrigation and dense planting (12 × 104 plants ha−1) adopted in both experiments. The control (CK) treatment consisted of the application of 540 mm of water during each irrigation interval. Compared with CK, the soil water content (SWC) in the 0–100 cm (particularly 0–60 cm) soil layers were lower during the water-insensitive growth periods (6th leaf-tasseling and milk-maturity stage) under both optimized DI and RDI. Furthermore, the daily crop evapotranspiration (DCE), phase water-consumption coefficient (K p), and ineffective crop evapotranspiration (ET c) were reduced by 12.6–35.1%, 3.4–9.9%, and 6.7–16.6%, respectively. Both the maximum leaf area index (LAI max) and biomass accumulation were maintained during the 6th leaf-milk stage. Under optimized DI and RDI, high maize yield was maintained (>15.0 Mg ha−1), WP c was increased (>2.7 Kg m−3), and irrigation water productivity (WP I) was increased by 10.3–33.4% and 36.0–41.3%, respectively. Optimized DI resulted in higher maize yields, but optimized RDI used less irrigation water. We propose that these optimized irrigation methods can improve maize yield and WP c in arid and semi-arid production areas. • Deficit irrigation (DI) and regulated deficit irrigation (RDI) were optimized. • Two optimizing irrigation methods can improve maize yield and water productivity. • RDI is superior to DI at reducing ineffective evapotranspiration. [ABSTRACT FROM AUTHOR]

Determining the water productivity of maize is of great significance for ensuring food security and coping with climate change. In 2018 and 2019, we conducted field trials in arid areas (Changji), semi-arid areas (Qitai) and semi-humid areas (Xinyuan). The hybrid XY335 was selected for the experiment, the planting density was 12.0 × 104 plants ha−1, and five irrigation amounts were set. The results showed that yield, biomass, and transpiration varied substantially and significantly between experimental sites, irrigation and years. Likewise, water use efficiency (WUE) for both biomass (WUEB) and yield (WUEY) were affected by these factors, including a significant interaction. Normalized water productivity (WP*) of maize increased significantly with an increase in irrigation. The WP* for film mulched drip irrigation maize was 37.81 g m−2 d−1; it was varied significantly between sites and irrigation or their interaction. We conclude that WP* differs from the conventional parameter for water productivity but is a useful parameter for assessing the attainable rate of film-mulched drip irrigation maize growth and yield in arid areas, semi-arid areas and semi-humid areas. The parametric AquaCrop model was not accurate in simulating soil water under film mulching. However, it was suitable for the prediction of canopy coverage (CC) for most irrigation treatments. [ABSTRACT FROM AUTHOR]

A critical step during rice ( Oryza sativa) cultivation is dense planting: a wider tiller angle will increase leaf shade and decrease photosynthesis efficiency, whereas a narrower tiller angle makes for more efficient plant architecture. The molecular basis of tiller angle remains unknown. This research demonstrates that tiller angle is controlled by a major quantitative trait locus, TAC1 ( Tiller Angle Control 1). TAC1 was mapped to a 35-kb region on chromosome 9 using a large F2 population from crosses between an indica rice, IR24, which displays a relatively spread-out plant architecture, and an introgressed line, IL55, derived from japonica rice Asominori, which displays a compact plant architecture with extremely erect tillers. Genetic complementation further identified the TAC1 gene, which harbors three introns in its coding region and a fourth 1.5-kb intron in the 3′-untranslated region. A mutation in the 3′-splicing site of this 1.5-kb intron from ‘AGGA’ to ‘GGGA’ decreases the level of tac1, resulting in a compact plant architecture with a tiller angle close to zero. Further sequence verification of the mutation in the 3′-splicing site of the 1.5-kb intron revealed that the tac1 mutation ‘GGGA’ was present in 88 compact japonica rice accessions and TAC1 with ‘AGGA’ was present in 21 wild rice accessions and 43 indica rice accessions, all with the spread-out form, indicating that tac1 had been extensively utilized in densely planted rice grown in high-latitude temperate areas and at high altitudes where japonica rice varieties are widely cultivated. [ABSTRACT FROM AUTHOR]