Response Of Grain Yield Research Articles

Efficacy of Soil and Foliar Boron Fertilizer on Boron Uptake and Productivity in Rice

This study examined the effect of B fertilizers applied by soil and foliar routes on the yield and total B uptake under glasshouse and field conditions. A high-yield rice variety, Sanpatong 1, was used in the experiments. In a pot experiment, soil B application produced a grain yield of 23.4 g pot−1, similar to the control treatment, but foliar B decreased grain yield by 14.9%. The total uptake of B was the highest at 2.5 mg pot−1 when soil B was applied, 66.7% higher than the in the control and foliar B application treatments, but there was no significant effect on the numbers of filled or unfilled grains. Similar responses of grain yield and total B uptake were observed in both conditions. Soil B application produced a grain yield of 4.7 t ha−1, similar to the control, but foliar B application decreased grain yield by 10.9%. The total uptake of B in the field was the highest at 4.7 mg m−2 when soil B was applied, being 42.4% higher than in the foliar B application and control treatments. This study indicates that the total uptake of B in rice plants can be successfully improved by applying soil B fertilizer, even though no effect was observed on productivity. The efficacy of B uptake in rice plants by soil B application is an interesting subject that should be further studied in greater detail to determine its utility in yield production, e.g., by splitting application times.

Effect of salinity stress on rice yield and grain quality: A meta-analysis

Salinity is one of the major abiotic stresses limiting the improvement in rice grain yield. The present study aimed to perform the meta-analysis and dose–response analysis using data collected from 58 studies to understand the responses of grain yield and grain quality traits to salinity stress. The results revealed that salinity stress reduced the grain yield (−64.52 %, 95 % confidence interval: −66.49 % to −62.44 %), primarily due to the decrease in the seed set rate, effective panicle number, and grain number per panicle. The effect of salinity initiated in the reproductive stage was more significant than that started in the seedling stage. In addition, alkaline salts had a higher impact on the grain yield compared with neutral salts. Salinity decreased the head rice rate and increased the chalky rice rate, adversely affecting the grain quality. However, salinity exhibited no significant effect on the length-to-width ratio, brown rice, and total milled rice. These results suggested that improving the effective panicle number and seed set rate is crucial for breeding salinity-tolerant rice cultivars. In addition, the grain quality should be considered while developing new rice cultivars for saline soil.

Effects of different shallow and saline groundwater depths on soil salinity, evapotranspiration, grain yield and spike traits of winter wheat

AbstractThe contribution of groundwater to evapotranspiration in crop irrigation scheduling is gaining importance worldwide. A two consecutive year wheat experiment was conducted in drainable lysimeters to evaluate the response of grain yield and quality, spike traits, water use efficiency, evapotranspiration and thousand kernel weight of wheat plants under twelve different shallow and saline groundwater conditions. The treatments included three groundwater depths (GWD) (D1: 30 cm, D2: 55 cm and D3: 80 cm) and four groundwater salinities (GWS) (S1: 0.38, S2: 2, S3: 4 and S4: 8 dSm−1). The results show that the average decrease in grain yield for D2and D1compared to D3was 20.9% and 30.7%, respectively, while the decrease for S2, S3and S4compared to S1was 11.8%, 18.0% and 25.1%. The highest evapotranspiration was found in the D3S1treatment (630.1 and 550.1 mm in 2017–2018 and 2018–2019, respectively), which increased by 48.0% and 30.2% in the first and second seasons, respectively, compared to the D1S4treatment. Thus, a GWD at 80 cm with 0.38 dSm−1GWS was able to meet 72% of the total water requirement of wheat under loam soil conditions. Water use efficiency values ranged from 1.49 to 1.65 kg m−3in the first season and from 1.18 to 1.73 kg m−3in the second season, with the highest water use efficiency values found at 80 cm GWD. Regression analysis showed that GWS had a greater effect on water use efficiency than GWD. On average, thousand kernel and hectolitre weights were highest under D3S1, reaching 49.6 g and 77.8 kg hl−1, respectively. Soil salinity increased steadily with increasing GWS at all GWD conditions, and higher soil salinity values were observed at 30 cm GWD. In addition, controlling a groundwater depth at 80 cm with 8.0 dSm−1GWS did not significantly increase soil salinity, which did not result in high grain yield losses. Finally, it is recommended to control groundwater at a constant depth of 80 cm with 0.38 dSm−1GWS after the tillering period of winter wheat to save more irrigation water, control soil salinity and improve yield and grain quality in the region with shallow‐saline groundwater.

The Response of Grain Yield and Quality of Water-Saving and Drought-Resistant Rice to Irrigation Regimes

Of all the crops, rice is the one that consumes the most water. Rice yields and quality are significantly influenced by irrigation. However, it is still unknown how different irrigation practices would affect the grain yield and quality of water-saving and drought-resistant rice. Hyou 518 (high-yielding rice variety) and Hanyou 73 (water-saving and drought-resistant rice variety) were employed as materials. Three irrigation regimes were set up in the field: conventional flooding irrigation (CF), alternate wetting and moderate soil drying irrigation (AWD), and dry cultivation (D). It was investigated how various irrigation regimes affected the two varieties’ yield and quality. The results revealed the following: 1. D considerably increased water-use efficiency while drastically reducing the yield, compared to CF and AWD. In comparison to other irrigation regimes, the grain yield and water use efficiency of Hanyou 73 enhanced synergistically under AWD treatment. 2. In contrast to CF treatment, AWD and D (especially) treatments decreased perfect rice kernel, total starch content, amylose content, amylopectin content, amylose/amylopectin, gel consistency, and breakdown, but increased green rice kernel, chalky kernel, protein content, and setback. 3. After heading, AWD and D lowered, and D treatment decreased more, the activities of ADP-glucose pyrophosphorylase (AGP), soluble starch synthase (SSS), and starch branching enzyme (SBE). AGP, SSS, and SBE were strongly inversely linked with perfect rice kernel, amylopectin content, gel consistency, and breakdown, but significantly negatively correlated with green rice kernel, chalky kernel, protein content, and setback. The results indicate that with AWD treatment, Hanyou 73 might provide a synergistic boost grain production, water-use efficiency, and quality. D treatment could significantly improve water-use efficiency. Compared with Hyou518, Hanyou 73 could maintain higher AGP, SSS, and SBE activities, head milled rice, perfect rice kernel, amylopectin content, and gel consistency under AWD and D treatment.

Responses of canopy functionality, crop growth and grain yield of summer maize to shading, waterlogging, and their combination stress at different crop stages

In the Huang-Huai-Hai region of China, continuous rain is the main meteorological constraint for summer maize, accompanied by stresses of both waterlogging and shading. To evaluate the independent and combined effects of shading and waterlogging on summer maize at different stages, a field experiment was performed to study the grain yield, crop growth, and canopy functionality of summer maize in response to waterlogging (W), shading (S), and their interaction for a 6 day period starting at the third leaf stage (V3), the sixth leaf stage (V6), and the tasseling stage (VT). Shading, waterlogging, and their combination stress (S+W) significantly decreased the grain yield of summer maize. Among these, the simultaneous stress induced greater yield losses than single stresses at any growth stage. The reduction of yield induced by waterlogging at early and late stages differed from 20–40 % to 3–16 %. Shading at VT stage induced most serious losses of grain yield. The grain yield of summer maize was closely related with the crop biomass accumulation. Shading, waterlogging, and their combination stress significantly decreased leaf area index resulting in serious reduction of the radiation interception. Besides, the leaf SPAD value and photosynthetic rate were also significantly reduced by the stresses, which led to notable reduction in radiation use efficiency (RUE) of summer maize. Thereby, the total accumulated crop biomass was decreased. Moreover, the biomass partitioning to ears was decreased. Accordingly, the 1000-kernel weight and kernels per ear were decreased by the stresses, leading to yield losses. This study explored the differential responses of radiation interception, canopy functionality, and RUE to waterlogging, shading, and their combined stress at different growth stage, furthering our understanding on the yield and growth for summer maize crops under persistent rainfall conditions.

Optimising the effect of nitrogen on winter oilseed rape grain yield in China: A meta-analysis

Winter oilseed rape is a nitrogen-sensitive oilseed crop with a crucial role in the Chinese edible oil market. However, there is a lack of systematic analysis of the effect of nitrogen (N) on the grain yield of winter oilseed rape. In this study, the response of the winter oilseed rape grain yield to N application was quantified and the key factors were identified, and we modeled the winter oilseed rape grain yield and economic benefits as functions of the N application rate. We found that the effects of N application on winter oilseed rape are sensitive to environmental factors and most agronomic management practices. Fertilizer management was the most important factor for improving the effectiveness of N application. We recommend two types of N management practices for winter oilseed rape production comprising basal application of controlled-release urea or combination application of basal and topdressing normal urea. In the latter case, the frequency of topdressing should be increased while ensuring that adequate basal fertilizer is applied. Other agronomic management practices such as direct seeding and increasing planting density may be important for further improving the effects of N application. The suitable N application levels for basal application of normal urea in the three production regions in northwest China, southwest China, and middle and lower reaches of the Yangtze River are 155.16–227.65 kg N ha–1, 219.15–225 kg N ha–1, and 259.38–284.36 kg N ha–1, respectively.

New Insights from Soil Microorganisms for Sustainable Double Rice-Cropping System with 37-Year Manure Fertilization

Long-term intensive use of mineral fertilizers in double rice-cropping systems has led to soil acidification and soil degradation. Manure fertilization was suggested as an alternative strategy to mitigate soil degradation. However, the effects of long-term mineral and manure fertilization on rice grain yield, yield stability, soil organic carbon (SOC) content, soil total nitrogen (TN) content, and the underlying mechanisms are unclear. Based on a long-term experiment established in 1981 in southern China, we compared four treatments: no fertilizer application (Control); application of nitrogen–phosphorus–potassium (NPK); NPK plus green manure in early rice (M1); and M1 plus farmyard manure in late rice and rice straw return in winter (M2). Our results showed that 37 years of NPK, M1, and M2 significantly increased rice grain yield by 54%, 46%, and 72%, and yield stability by 22%, 17%, and 9%, respectively. M1 and M2 significantly increased SOC content by 39% and 23% compared to Control, respectively, whereas there was no difference between Control and NPK. Regarding soil TN content, it was significantly increased by 8%, 46%, and 20% by NPK, M1, and M2, respectively. In addition, M2 significantly increased bacterial OTU richness by 68%, Chao1 index by 79%, and altered the bacterial community composition. Changes in soil nutrient availability and bacterial Simpson index were positively correlated with the changes in grain yield, while shifts in bacterial community were closely related to yield stability. This study provides pioneer comprehensive assessments of the simultaneous responses of grain yield, yield stability, SOC and TN content, nutrient availability, and bacterial community composition to long-term mineral and manure fertilization in a double rice-cropping system. Altogether, this study spanning nearly four decades provides new perspectives for developing sustainable yet intensive rice cultivation to meet growing global demands.

Varietal Variances of Grain Nitrogen Content and Its Relations to Nitrogen Accumulation and Yield of High-Quality Rice under Different Nitrogen Rates

Nitrogen (N) management is an important strategy for improving the yield, grain quality, and N use efficiency of rice (Oryza sativa). Exploring appropriate N application rates is essential for high-quality rice production in China, especially in the context of the large extension of these varieties in recent years. Field experiments were conducted to study changes of grain N content and their correlations to yield and yield components using twenty high-quality rice varieties grown at three N application rates (105, 165 and 225 kg ha−1) in 2019 and 2020. Additionally, a micro-plot experiment based on 15N isotope tracing technique was also conducted with two contrasting high-quality rice varieties of Y-liangyou 911 and Yeiangyoulisi under two N application rates (165 and 225 kg ha−1) in 2021, with grain N accumulation, its subdivision, and N utilization investigated. We found that the grain N content of high-quality rice increased with the increase of N application rates, while there was no consistent response in grain yield. There was a significant quadratic relationship between grain yield and grain N content, while panicles m−2 and grain-setting rate had a positive and a negative correlation with grain N content, respectively, in both 2019 and 2020. Across three N application rates and two years, the coefficient of variation (CV) of grain N content ranged from 10.36% to 21.26% among twenty varieties, of which Y-liangyou 911 had the smallest CV, and six varieties, including Yexiangyoulisi, had the largest CV. The micro-plot experiment showed that, in comparison with N165, the grain N content, grain N accumulation, and N recovery rate increased under N225 in both varieties, but a significant increase in grain yield was only observed for Y-liangyou 911. Grain N accumulation derived from panicle N fertilizer and its ratios to total grain N accumulation and the N recovery rate was significantly higher than those derived from basal and tillering N fertilizers. Nevertheless, increasing N application rates had much greater effects on the grain N accumulation derived from basal and tillering fertilizers and on ratios to total grain N accumulation in Yexiangyoulisi than those in Y-liangyou 911. Our results suggested that adopting a moderate N application rate (165 kg ha−1) is conducive to maintaining an appropriate grain N content and achieving higher grain yield and N use efficiency as well as better quality of high-quality rice. Besides, moderately reducing basal and/or tillering N fertilizers is necessary for those varieties with a larger CV of grain N content.

High nitrogen input increases the total spikelets but decreases the high-density grain content in hybrid indica rice

Nitrogen (N) application strongly affects both the total spikelets and grain weight in rice ( Oryza sativa L.), thereby affecting grain yield. Grain weight is closely related to the grain-filling process after the heading stage, and can be regarded as a combination of grain size and grain density (GD). However, there is a lack of information about the response of GD in rice to N. Here, we examined in a lager panicle hybrid indica rice at two field experimental sites the responses of grain traits (including GD), grain yield, and yield components to various N treatments and their relationships with each other. In this study, the grains with six GD ranges were fractionated into the light grain (1.00 g ml −1 ≤ GD < 1.15 g ml −1 ) and heavy grain or high-density grain (GD ≥ 1.15 g ml −1 ). High N application increased the total spikelets m −2 , but did not result in high grain yield due to reduced grain weight (seed-setting rate and 1000-grain weight). Reduction of the 1000-grain weight under high N was related to the decrease in grain volume and high-density grain content (the ratio of the weights of high-density grains to the total grains weight). As N application increased from 0 to 225 kg ha −1 , on average, the high-density grain content decreased by 31.93 %, from 78.21 % to 53.24 %. Grain plumpness and GD were the main factors affecting grain weight. GD was more important to the grain weight when grain size was smaller, and plumpness degree and GD were both crucial for grain weight when grain volume was larger. Compared with light grains, heavy grains had higher amylose content and lower crude protein content. These results indicated that the constraint and compensation relationship between spikelet number and grain weight in rice was also reflected in the equilibrium between grain size and GD. Although high N input in rice production increased the total spikelets m −2 , high N input decreased the grain volume, especially the high-density grain content. • High nitrogen application reduced the high-density (≥ 1.15 g ml −1 ) grain content. • Rice quality of heavy grain was different from that of light grain. • For larger-volume grain, both plumpness and density affected grain weight. • There were constraint and compensation between grain size and grain density.

Response of Grain Yield and Water Use Efficiency to Irrigation Regimes during Mid-Season indica Rice Genotype Improvement

Understanding the performance of rice (Oryza sativa L.) agronomic traits and efficiency in water usage as well as grain yield under various irrigation regimes is crucial to achieving high resource use efficiency and high yield. In this study, 12 mid-season indica rice genotypes that have been grown in the lower reaches of the Yangtze River for the past 80 years were studied in a field experiment for two years under two irrigation regimes, i.e., conventional irrigation (CI) and alternate wetting and drying irrigation (AWD). The results showed that with genotype improvement in irrigation regimes, the total number of spikelets, shoot and root dry weight, root oxidation activity, total leaf area index (LAI), effective LAI, leaf photosynthetic rate, and abscisic acid contents and zeatin + zeatin riboside contents in root bleeding sap were significantly increased at main growth stages. AWD irrigation synchronously increased rice resource use efficiency (water use efficiency (WUE), radiation use efficiency (RUE), and temperature use efficiency (TUE)) and grain yield. Compared to CI, AWD more significantly enhanced the performances of rice genotypes in all studied traits. Based on our findings, a semi-dwarf hybrid rice genotype has great potential for high resource use efficiency and high yield under alternate wetting and drying irrigation, which was attributed to the improved agronomic characteristics and superior root traits.

Yield Attributes Response to Nitrogen Fertilization in Low-Nitrogen Tolerant Hybrid Rice

The development of low-nitrogen (N) tolerant varieties is an effective way to improve the use efficiency of N in rice and is crucial to the sustainable rice production in China. Recently, we observed that higher grain yields were obtained in the hybrid rice variety Deyou 4727 (DY4727) than in the hybrid rice variety Y-liangyou 900 (YLY900) under zero-N fertilization conditions, suggesting that DY4727 has higher low-N tolerance compared to YLY900. In this study, field experiments were performed in 2020 and 2021 to compare the responses of yield attributes to N fertilization (180 kg N ha–1) relativized to zero-N fertilization between DY4727 and YLY900. Results showed that the response of grain yield to N fertilization was 13–55% for two varieties in two years. DY4727 had lower response of grain yield to N fertilization than YLY900 by 47% in 2020 and by 70% in 2021. There were no significant or consistent differences in responses of spikelets per m2, spikelet filling percentage, aboveground biomass, intercepted radiation, radiation use efficiency, and aboveground N uptake to N fertilization between DY4727 and YLY900. DY4727 had 32% and 26% lower positive response of grain weight to N fertilization compared to YLY900 in 2020 and 2021, respectively. The response of harvest index to N fertilization was negative (−3% in 2020 and −9% in 2021) for DY4727 but positive (1% in 2020 and 12% in 2021) for YLY900. DY4727 had higher negative response of internal N-use efficiency to N fertilization (−41% in 2020 and −24% in 2021) than YLY900 (−11% in 2020 and −10% in 2021). This study suggests that grain weight, harvest index, and internal N-use efficiency are key traits determining the difference in response of grain yield to N fertilization between DY4727 and YLY900.

Effect of Irrigation, Nitrogen Sources, and Metribuzin on Performance of Maize and Its Weeds

ABSTRACT Exploiting water and nutrients by crop plants is limiting by abundance of undesirable plant species viz weeds due to their competitiveness ability, affecting crop productivity and quality. Thus, over two seasons of 2017 and 2018, field experiment was carried out at the Experimental Farm of Faculty of Agriculture, Ain Shams University, Egypt to study the response of maize grain yield and its nutrient constituents and associated weeds to two irrigation intervals (every 15 and 22 days), three weed control treatments (hoeing twice, metribuzin, and unweeded) as well as three nitrogen forms (ammonium nitrate, ammonium sulfate, and urea). The tested factors distributed in a strip plots design with four replications. The results showed that dry weight of grasses (56.1 g m−2) and total weeds (67.2 g m−2) were lower with irrigation every 15 day. Irrigation every 15 day gave the maximum increase in plant height (233 cm), ear length (18.4 cm), ear diameter (4.7 cm), 100 grain weight (28.0 g), grain yield (7.58 ton ha−1) and leaf P (0.29%) and K (2.07%) contents. Hoeing gave the lowest biomass of grasses, total weeds and weeds potassium content, while metribuzin was the superior in diminishing broadleaf weed biomass. Hoeing was as similar as metribuzin as in enhancing plant height, ear length, 100 grain weight and grain yield ton ha–1. Nitrogen (N) form had no significant effect on weed biomass. However, ammonium nitrate was the most effective form at promoting 100 grain weight, ear length, grain yield ton ha–1 and maize leaf potassium content. Results exhibited that irrigating maize fields every 15 day × hoeing or metribuzin × ammonium sulfate–N could be a combatable and integrative pattern for diminishing weed growth and keeping crop productivity.

The response of grain yield and ear differentiation related traits to nitrogen levels in maize varieties with different nitrogen efficiency

Maize (Zea mays L.) is one of the most widely distributed and important crops in China. Maize ear differentiation plays an important role grain yield formation. However, it is unclear if ear and root morphophysiology status affects yield formation by altering ear differentiation and development under different nitrogen (N) conditions. The aim of this study is to understand how the ear differentiation and development are affected by ear and root morphophysiology traits, as affected by the N rate. The experiment consisted of two N rates: high nitrogen (180 kg ha−1), and low nitrogen (60 kg ha−1). Two N-efficient varieties (NEVs) and two N-inefficient varieties (NIVs) were grown in the field. The results showed higher nitrogen accumulation and grain yield in NEVs than in NIVs, which was mainly attributed to the increased N uptake by the larger root system under both N conditions. Under high N conditions, among ear differentiation-related traits, only FR was significantly positively correlated with grain yield, and NEVs ensure FR through higher N concentration and ZR content in ear at the fertilization stage. Under low N conditions, NEVs obtained higher FP, SR and FR through higher N concentration and IAA in ear at the early stage of ear differentiation, maintained lower AR and BTL by higher RA, R-ZR and E-ZR at the late stage of ear growth. These results suggest that NEVs have a more complex mechanism for obtaining higher grain yield under low N conditions than N sufficiency, and that phytohormones play an important role in this process.

Divergent response of hay and grain yield of oat: effects of environmental factors and sowing rate.

Oat (Avena sativa L.) is recognized for its impressive productivity in marginal environments, and the sowing rate is an important crop management practice that potentially enhances oat productivity. Previous studies have reported the effect of sowing rate on oat yield; however, the results from such studies are inconsistent. Thus, based on 43 studies across eight countries, this study aimed to assess changes in hay and grain yields in response to sowing rate and, in combination with a boosted regression tree, to evaluate and rank the dominant factors (e.g. climate conditions, soil conditions, and sowing rate) affecting changes in hay and grain yields of oat. The results revealed that increasing the sowing rate significantly increased the response ratio of grain yields and hay yields by averages of 7.3% and 7.9% respectively. However, the response ratios of grain yields and hay yields in response to changes in sowing rate were affected by different factors. Climate condition and mean annual precipitation primarily affected the response ratios of hay yields, whereas the sowing rate dominated changes in the response ratios of grain yields, with the response ratios of grain yields peaking at a sowing rate of 85 kg ha-1 . Optimizing the sowing rate with site-specific environmental conditions could be a potential strategy for profitable oat production, given that oat can be produced under marginal environments (e.g. cool-wet climates and soil with low fertility). © 2022 Society of Chemical Industry.

Grain yield and nitrogen use efficiency of an ultrashort-duration variety grown under different nitrogen and seeding rates in direct-seeded and double-season rice in Central China

Nitrogen (N) and seeding rates are important factors affecting grain yield and N use efficiency (NUE) in direct-seeded rice. However, these factors have not been adequately investigated on direct-seeded and double-season rice (DDR) in Central China. The objective of this study was to evaluate the effects of various N and seeding rates on the grain yield and NUE of an ultrashort-duration variety grown under DDR. Field experiments were conducted in 2018 in Wuxue County and 2019 in Qichun County, Hubei Province, China with four N rates and three seeding rates. The results showed that the grain yield of the ultrashort-duration variety ranged from 6.32 to 8.23 t ha–1 with a total growth duration of 85 to 97 days across all treatments with N application. Grain yield was increased significantly by N application in most cases, but seeding rate had an inconsistent effect on grain yield. Furthermore, the response of grain yield to the N rates was much higher than the response to seeding rates. The moderate N rates of 100–150 and 70–120 kg N ha–1 in the early and late seasons, respectively, could fully express the yield potential of the ultrashort-duration variety grown under DDR. Remarkably higher N responses and agronomic NUE levels were achieved in the early-season rice compared with the late-season rice due to the difference in indigenous soil N supply capacity (INS) between the two seasons. Seasonal differences in INS and N response should be considered when crop management practices are optimized for achieving high grain yield and NUE in ultrashort-duration variety grown under DDR.

Earbox, an open tool for high-throughput measurement of the spatial organization of maize ears and inference of novel traits

BackgroundCharacterizing plant genetic resources and their response to the environment through accurate measurement of relevant traits is crucial to genetics and breeding. Spatial organization of the maize ear provides insights into the response of grain yield to environmental conditions. Current automated methods for phenotyping the maize ear do not capture these spatial features.ResultsWe developed EARBOX, a low-cost, open-source system for automated phenotyping of maize ears. EARBOX integrates open-source technologies for both software and hardware that facilitate its deployment and improvement for specific research questions. The imaging platform consists of a customized box in which ears are repeatedly imaged as they rotate via motorized rollers. With deep learning based on convolutional neural networks, the image analysis algorithm uses a two-step procedure: ear-specific grain masks are first created and subsequently used to extract a range of trait data per ear, including ear shape and dimensions, the number of grains and their spatial organisation, and the distribution of grain dimensions along the ear. The reliability of each trait was validated against ground-truth data from manual measurements. Moreover, EARBOX derives novel traits, inaccessible through conventional methods, especially the distribution of grain dimensions along grain cohorts, relevant for ear morphogenesis, and the distribution of abortion frequency along the ear, relevant for plant response to stress, especially soil water deficit.ConclusionsThe proposed system provides robust and accurate measurements of maize ear traits including spatial features. Future developments include grain type and colour categorisation. This method opens avenues for high-throughput genetic or functional studies in the context of plant adaptation to a changing environment.

Maize grain yield responses to realistic biochar application rates on smallholder farms in Kenya

Despite efforts to increase agricultural production sustainably in sub-Saharan Africa, large gaps remain between actual and potential yield of food crops. Adding biochar to degraded cropland soils in the African tropics has significant potential to enhance crop productivity. Biochar-based farming can also mitigate climate change, through soil carbon storage. This study involved six smallholder farms at sites in eastern, central, and western Kenya that are characterized by different pedo-climatic conditions. We examined the response of non-fertilized and fertilized maize monoculture to three dosages of biochar that are realistic for domestic production by farmers at each of the sites over four growing seasons. Commonly available biomass wastes in each agro-ecosystem (coconut shells, coffee husks, maize cobs) were used as feedstock for biochar, which was applied at 1, 5, and 10 Mg ha−1 at the start of the experiment. Across seasons and fertilizer treatments, maize grain yield (dry matter) showed consistently positive responses, with an average increase of 1.0, 2.6, and 4.0 Mg ha−1, respectively, above the control for the three biochar application rates. Absolute responses of maize grain yield to specific biochar doses were similar across the four investigated seasons and replicate farms within sites, and uncorrelated to yield levels in the control treatment. Here, we show for the first time that yield response to biochar decreased with increasing application rate, indicating that it may be better to spread a given amount of biochar over a large area rather than concentrating it to a smaller area, at least when biochar is applied along plant rows at rates ≥1 Mg ha−1, as in our experiment. This study demonstrated that application of biochar, locally produced from available biomass residues, is a promising approach to enhance agricultural production and carbon storage on smallholder farms under a wide range of pedo-climatic conditions in Kenya.

Responses of Growth and Grain Yield of IR50404 Rice to Temperature Stress

Climate changes, rising warmth, drought, and CO2, are now seriously influencing agriculture. In this study, four separate greenhouses (labeled GH1, GH2, GH3, and GH4) were built with plastic roofs and walls, except GH1, which had three walls with mesh to evaluate the impact of temperature stress on growth, biomass, and yield of rice variety IR50404 under different temperature regimes. The control treatment group was grown ambient, next to these greenhouses. GH1, GH2, GH3, and GH4’s temperatures were from 0.9 oC to 3.1 oC higher than the ambient (as control). Carbon dioxide concentrations in GH2, GH3, and GH4 were recorded higher than the ambient, from 34.1 ppm to 48.2 ppm. Total vegetative dry matter was reduced from 15.9% to 20.5%, while grain yield declined from 20.8% to 24.6% when the mean temperature increased from 2.9 oC to 3.1 oC. High temperature or a combination of high-temperature stress with elevated CO2 concentration reduced the grain yield and total vegetative dry matter.

The impacts of post-anthesis warming on grain yield and quality of double-cropping high-quality indica rice in Jiangxi Province, China

In southern China, climate warming threatens rice production in double rice cropping systems. However, the actual responses of grain yield and quality of high-quality indica rice to climate warming in double rice cropping systems are still unclear. Therefore, a 2-year field post-anthesis warming experiment was conducted by using two high-quality indica rice cultivars (e.g., Qiliangyou2012, early rice; Taiyou398, late rice). The results showed that post-anthesis warming (PAW) increased the rice canopy daily mean temperatures from heading to maturity by an average of 1.9 °C and 2.0 °C over the two years in the early and late rice seasons, respectively. The grain yield, filled grain percentage, and grain weight were not affected by PAW for either early or late rice in the two years. For early rice, PAW decreased the head rice rate and setback, whereas it increased the chalky grain rate, chalkiness, peak viscosity, breakdown, pasting temperature, protein and most amino acid contents. Similarly, the head rice rate, amylose content, and setback of late rice were decreased, whereas the chalky grain rate, chalkiness, peak viscosity, breakdown, protein and most amino acid contents were increased under PAW conditions. These results suggested that PAW worsened the grain milling and appearance qualities and improved the rice eating and nutritional qualities for both early and late rice, while it reduced the cooking quality of early rice. This study provides new insight into improving the grain yield and quality of high-quality indica rice in a double rice cropping system under future climate warming conditions.

Responses of rice (Oryza sativa L.) plant growth, grain yield and quality, and soil properties to the microplastic occurrence in paddy soil

Responses of rice (Oryza sativa L.) plant growth, grain yield and quality, and soil properties to the microplastic occurrence in paddy soil