The unpredictability and large fluctuation of the climatic conditions in rainfed regions do affect spring wheat yield and grain quality. These variations offer the opportunity for the production of ...better quality wheat. The effect of variable years, locations and sowing managements on wheat grain yield and quality was studied through field experiments using three genotypes, three locations for two years under rainfed conditions. The two studied years as contrasting years at three locations and sowing dates depicted variability in temperature and water stress during grain filling which resulted considerable change in grain yield and quality. Delayed sowing, years (2009-10) and location (Talagang) with high temperature and water stress resulted increased proline, and grain quality traits i.e. grain protein (GP) and grain ash (GA) than optimum conditions (during 2008-09, at Islamabad and early sowing). However, opposite trend was observed for dry gluten (DG), sodium dodecyl sulphate (SDS), SPAD content and grain yield irrespective of genotypes. The influence of variable climatic conditions was dominant in determining the quality traits and inverse relationship was observed among some quality traits and grain yield. It may be concluded that by selecting suitable locations and different sowing managements for subjecting the crop to desirable environmental conditions (temperature and water) quality traits of wheat crop could be modified.
Unmanned Aerial Vehicles and Systems (UAV or UAS) have become increasingly popular in recent years for agricultural research applications. UAS are capable of acquiring images with high spatial and ...temporal resolutions that are ideal for applications in agriculture. The objective of this study was to evaluate the performance of a UAS-based remote sensing system for quantification of crop growth parameters of sorghum (Sorghum bicolor L.) including leaf area index (LAI), fractional vegetation cover (fc) and yield. The study was conducted at the Texas A&M Research Farm near College Station, Texas, United States. A fixed-wing UAS equipped with a multispectral sensor was used to collect image data during the 2016 growing season (April-October). Flight missions were successfully carried out at 50 days after planting (DAP; 25 May), 66 DAP (10 June) and 74 DAP (18 June). These flight missions provided image data covering the middle growth period of sorghum with a spatial resolution of approximately 6.5 cm. Field measurements of LAI and fc were also collected. Four vegetation indices were calculated using the UAS images. Among those indices, the normalized difference vegetation index (NDVI) showed the highest correlation with LAI, fc and yield with R2 values of 0.91, 0.89 and 0.58 respectively. Empirical relationships between NDVI and LAI and between NDVI and fc were validated and proved to be accurate for estimating LAI and fc from UAS-derived NDVI values. NDVI determined from UAS imagery acquired during the flowering stage (74 DAP) was found to be the most highly correlated with final grain yield. The observed high correlations between UAS-derived NDVI and the crop growth parameters (fc, LAI and grain yield) suggests the applicability of UAS for within-season data collection of agricultural crops such as sorghum.
China has a unique cotton planting pattern. Cotton is densely planted in alternating wide and narrow rows to increase yield in Xinjiang, China, causing the difficulty in the accurate estimation of ...cotton yield using remote sensing in such field with branches occluded and overlapped.
In this study, unmanned aerial vehicle (UAV) imaging and deep convolutional neural networks (DCNN) were used to estimate densely planted cotton yield. Images of cotton fields were acquired by the UAV at an altitude of 5 m. Cotton bolls were manually harvested and weighed afterwards. Then, a modified DCNN model (CD-SegNet) was constructed for pixel-level segmentation of cotton boll images by reorganizing the encoder-decoder and adding dilated convolutions. Besides, linear regression analysis was employed to build up the relationship between cotton boll pixels ratio and cotton yield. Finally, the estimated yield for four cotton fields were verified by weighing harvested cotton. The results showed that CD-SegNet outperformed the other tested models, including SegNet, support vector machine (SVM), and random forest (RF). The average error in yield estimates of the cotton fields was as low as 6.2%.
Overall, the estimation of densely planted cotton yields based on low-altitude UAV imaging is feasible. This study provides a methodological reference for cotton yield estimation in China.
TaCKX wheat gene family members (GFMs) encode the enzyme cytokinin oxidase/dehydrogenase (CKX), which irreversibly degrades cytokinins. The genes are important regulators of cytokinin content and ...take part in growth and development, with a major impact on yield-related traits. The goal of this research was to test whether these genes might be differentially expressed in the field compared to laboratory conditions and consequently differently affect plant development and yield.
We compared expression and crosstalk of the TaCKX GFMs and TaNAC2-5A gene in modern varieties grown in a growth chamber (GC) and in the field and looked for differences in their impact on yield-related traits. The TaNAC2-5A gene was included in the research since it was expected to play an important role in co-regulation of these genes. The range of relative expression levels of TaCKX GFMs and TaNAC2-5A gene among tested cultivars was from 5 for TaCKX8 to more than 100 for TaCKX9 in the GC and from 6 for TaCKX8 to 275 for TaCKX10 in the field. The range was similar for four of them in the GC, but was much higher for seven others and TaNAC2-5A in the field. The TaCKX GFMs and TaNAC2-5A form co-expression groups, which differ depending on growth conditions. Consequently, the genes also differently regulate yield-related traits in the GC and in the field. TaNAC2-5A took part in negative regulation of tiller number and CKX activity in seedling roots only in controlled GC conditions. Grain number and grain yield were negatively regulated by TaCKX10 in the GC but positively by TaCKX8 and others in the field. Some of the genes, which were expressed in seedling roots, negatively influenced tiller number and positively regulated seedling root weight, CKX activity in the spikes, thousand grain weight (TGW) as well as formation of semi-empty spikes.
We have documented that: 1) natural variation in expression levels of tested genes in both environments is very high, indicating the possibility of selection of beneficial genotypes for breeding purposes, 2) to create a model of an ideotype for breeding, we need to take into consideration the natural environment.
The use of compost made from the leaves of Juglans regia has long been controversial because of its inhibitory effect due to the presence of juglone. Therefore, the aim of our study was to replicate ...the typical habits of farmers and gardeners, where the dried leaves are collected at the end of the season and placed in a composter. Then, the effects of the different treatments on the yield of the plant (lettuce), secondary metabolism, and possible toxicity of the compost of the grown plant were evaluated. The lowest yield of lettuce was obtained in soil with composted walnut and hazelnut leaves, while the highest yield was recorded in in soil with compost control, soil with composted walnut leaves and grass with the addition of composting agent and soil with composted walnut leaves with addition of composting agent. Some allelochemicals were still present in the compost but at such low levels that they did not affect yield. We suggest that dry walnut leaves and cut grass can be used for composting, while dry hazelnut leaves still contain some allelochemicals after two years that significantly inhibit plant growth and thus yield, so we would not recommend their use for composting.
Improved knowledge of the size and velocity dependences of the normal restitution coefficient (NCOR) is necessary for extending the NCOR laboratory results to practical rockfall trajectory analysis. ...Hence, a new normal impact device was developed for conducting laboratory impact tests of marble spheres under a wide range of impact velocities. Compression tests of marble spheres were also conducted. A new viscoelastoplastic contact model was proposed, and the size- and rate-dependent contact yield strength was considered for the first time. The results of compression tests demonstrate that the contact yield strength is strongly size-dependent. The size effect of the NCOR at low impact velocities is opposite that at higher impact velocities. The theoretical NCOR that was obtained from the proposed model with size- and rate-dependent strength shows satisfactory agreement with the experimental results. The complex size and velocity dependences of the NCOR are well captured by the proposed model. The theoretical results clearly demonstrate that the influence of the size on the NCOR substantially exceeds that of the impact velocity. The viscosity determines the NCOR for small marble spheres at low impact velocities, and plasticity is the dominant factor that determines the NCOR of large marble spheres at high impact velocities.
Summary
Phytochrome‐interacting factors (PIFs) play major roles in regulating plant growth and development, but their roles in drought stress remain elusive. Here, we cloned and characterized a maize ...(Zea mays) PIF transcription factor, ZmPIF1. The expression level of ZmPIF1 was significantly induced by independent drought and abscisic acid (ABA) treatments. The ZmPIF1 transgenic rice and Arabidopsis displayed water saving and drought resistance, which were associated with reduced a stomatal aperture and transpiration rate. Moreover, the ZmPIF1 transgenic rice were hypersensitive to exogenous ABA, while the endogenous ABA level was not significantly changed, suggesting that ZmPIF1 was a positive regulator of the ABA signalling pathway. Digital gene expression (DGE) results further indicated that ZmPIF1 participated in ABA signalling pathway and regulated the stomatal aperture in rice. In addition, grain yield and agronomic traits analysis over 4 years showed that ZmPIF1 was able to increase the grain yield through an increase in tiller and panicle numbers in transgenic rice. Overall, ZmPIF1 plays an important role in the ABA‐mediated regulation of stomatal closure to control water loss. ZmPIF1 can enhance water saving and drought resistance and improve the crop yield in rice, illustrating the capacity of ZmPIF1 for crop improvement.
Acclimation in plants – the Green Hub consortium Kleine, Tatjana; Nägele, Thomas; Neuhaus, H. Ekkehard ...
The Plant journal : for cell and molecular biology,
April 2021, 2021-04-00, 20210401, Letnik:
106, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Summary
Acclimation is the capacity to adapt to environmental changes within the lifetime of an individual. This ability allows plants to cope with the continuous variation in ambient conditions to ...which they are exposed as sessile organisms. Because environmental changes and extremes are becoming even more pronounced due to the current period of climate change, enhancing the efficacy of plant acclimation is a promising strategy for mitigating the consequences of global warming on crop yields. At the cellular level, the chloroplast plays a central role in many acclimation responses, acting both as a sensor of environmental change and as a target of cellular acclimation responses. In this Perspective article, we outline the activities of the Green Hub consortium funded by the German Science Foundation. The main aim of this research collaboration is to understand and strategically modify the cellular networks that mediate plant acclimation to adverse environments, employing Arabidopsis, tobacco (Nicotiana tabacum) and Chlamydomonas as model organisms. These efforts will contribute to ‘smart breeding’ methods designed to create crop plants with improved acclimation properties. To this end, the model oilseed crop Camelina sativa is being used to test modulators of acclimation for their potential to enhance crop yield under adverse environmental conditions. Here we highlight the current state of research on the role of gene expression, metabolism and signalling in acclimation, with a focus on chloroplast‐related processes. In addition, further approaches to uncovering acclimation mechanisms derived from systems and computational biology, as well as adaptive laboratory evolution with photosynthetic microbes, are highlighted.
Significance Statement
Acclimation allows plants to adapt at the physiological level to changes in their environment, and is pivotal to plant fitness, especially in the light of global warming. The Green Hub consortium aims to understand and enhance the protective effects of the cellular networks that mediate acclimation of plants including crops.
Compound weather events may lead to extreme impacts that can affect many aspects of society including agriculture. Identifying the underlying mechanisms that cause extreme impacts, such as crop ...failure, is of crucial importance to improve their understanding and forecasting. In this study, we investigate whether key meteorological drivers of extreme impacts can be identified using the least absolute shrinkage and selection operator (LASSO) in a model environment, a method that allows for automated variable selection and is able to handle collinearity between variables. As an example of an extreme impact, we investigate crop failure using annual wheat yield as simulated by the Agricultural Production Systems sIMulator (APSIM) crop model driven by 1600 years of daily weather data from a global climate model (EC-Earth) under present-day conditions for the Northern Hemisphere. We then apply LASSO logistic regression to determine which weather conditions during the growing season lead to crop failure. We obtain good model performance in central Europe and the eastern half of the United States, while crop failure years in regions in Asia and the western half of the United States are less accurately predicted. Model performance correlates strongly with annual mean and variability of crop yields; that is, model performance is highest in regions with relatively large annual crop yield mean and variability. Overall, for nearly all grid points, the inclusion of temperature, precipitation and vapour pressure deficit is key to predict crop failure. In addition, meteorological predictors during all seasons are required for a good prediction. These results illustrate the omnipresence of compounding effects of both meteorological drivers and different periods of the growing season for creating crop failure events. Especially vapour pressure deficit and climate extreme indicators such as diurnal temperature range and the number of frost days are selected by the statistical model as relevant predictors for crop failure at most grid points, underlining their overarching relevance. We conclude that the LASSO regression model is a useful tool to automatically detect compound drivers of extreme impacts and could be applied to other weather impacts such as wildfires or floods. As the detected relationships are of purely correlative nature, more detailed analyses are required to establish the causal structure between drivers and impacts.
Citrus trees infected with ‘Candidatus Liberibacter asiaticus’, the bacterium associated with huanglongbing (HLB), present asymmetric chlorosis and yellow veins on leaves, nutritional deficiencies ...due to impaired water and nutrient uptake by a reduced root system, and also premature fruit drop and progressive yield reduction. This motivates growers to adopt additional foliar nutritional and auxin plant hormone derivative 2,4-D sprays to try to mitigate HLB damage. However, long-term studies that compare the yield of both well-nourished asymptomatic (AT) and symptomatic trees (ST) under these programs are absent in the literature. This work presents a long-term field study that compared the effect of several enhanced nutritional programs (ENP) and exogenous auxin spray on the progress of HLB severity and on the fruit drop and yield of AT and ST. Moreover, the benefit–cost ratio of each program was estimated. Programs did not contribute to reduce HLB severity over time (mean final HLB severity > 50%). None of the programs contributed to reduce the percentage of fruit drop (remained higher than 40% in symptomatic branches) nor to increase fruit production of ST. Benefit/cost ratio was, on average, 1.49 times higher in AS than in ST. Grower standard nutritional program had the higher benefit-cost ratio (132.8 and 84.7 for AT and ST, respectively) than the others more costly programs. These observations suggest that ENP and 2,4-D sprays are not important in controlling HLB nor mitigating its damages, and their use, instead of removing diseased trees, can build up inoculum within a region. Diseased trees are inoculum source that psyllid vector Diaphorina citri can acquire the bacteria, transmit to a healthy tree, and, consequently, spread HLB. Rigorous vector control by insecticide sprays and eradication of diseased plants are still the best long-term HLB control.
Display omitted
•First study that compared the effect of enhanced nutrition on yield and fruit drop of nourished healthy and diseased plants.•Tested mineral and auxin supplementation has no effect on reducing HLB severity progress and yield decline in diseased tree.•Standard nutritional treatment resulted in a better benefit/cost ratio, for both healthy and diseased trees.
PDF
