Mature Growth Stages Research Articles

Performance of dairy cows offered silages produced from grass swards harvested on either three or five occasions during the growing season

The nutritive value of grass silage can be improved by harvesting herbage at a less mature growth stage, which in practice usually involves more frequent harvests. This study examined the performance of dairy cows offered grass silages produced from perennial ryegrass (Lolium perenne) based swards harvested at 2 different frequencies during the growing season (3-harvest (3H) vs. 5-harvest (5H)). Thirty-four mid-lactation (av. 147 d in milk) dairy cows (30 multiparous, 4 primiparous) were offered either 3H or 5H silages in a continuous design (21 wk) experiment. Within each treatment cows were offered silage from each harvest (in harvest number order) for a pre-determined number of days in proportion to herbage DM yield at each harvest. Silages were offered ad libitum while a common concentrate was offered to all cows at 12.0 kg per cow/d over the first 15 wk of the study, 8.0 kg per cow/d during wk 16 -19 and 6.0 kg cow/d during wk 20 - 21. Total yield of herbage harvested over the season from within 3H and 5H were 12.6 and 11.2 t DM/ha, respectively. Across all harvests the mean ME and CP concentration of silages were 10.9 MJ/kg DM and 131 g/kg DM for 3H, and 11.5 MJ/kg DM and 152 g/kg DM for 5H. Silage DMI was greater for cows offered 5H silages compared with 3H silages (14.1 vs. 11.7 kg/d, respectively). Cows offered 5H silages had a greater daily milk yield (33.5 vs. 31.9 kg) and ECM yield (37.4 vs. 35.6 kg) compared with cows offered 3H silages. Treatment had no effect on milk fat or protein concentration. Cows offered 5H silages produced milk with greater concentrations of CLA and n-3 fatty acids. Treatment had no effect on mean BW or BCS, or on efficiency metrics such as milk yield or ECM yield per kg of DMI. Molar proportions of VFA in ruminal fluid differed between the treatments, with cows offered 3H silages having higher proportion of total butyrate (15.9 vs. 14.4% of total VFA) and lower total valerate (3.2 vs. 3.7% of total VFA) compared with those offered 5H. The acetate: propionate and acetate plus butyrate: propionate ratios were unaffected by treatment. In conclusion, increasing herbage harvesting frequency from 3 to 5 times per year improved the nutritional value of the resulting silages, and this led to higher silage DMI, milk yield and ECM yield. However, overall production efficiency (ECM/DMI) was unaffected by treatment.

Assessing Maize Yield Spatiotemporal Variability Using Unmanned Aerial Vehicles and Machine Learning

Optimizing the prediction of maize (Zea mays L.) yields in smallholder farming systems enhances crop management and thus contributes to reducing hunger and achieving one of the Sustainable Development Goals (SDG 2—zero hunger). This research investigated the capability of unmanned aerial vehicle (UAV)-derived data and machine learning algorithms to estimate maize yield and evaluate its spatiotemporal variability through the phenological cycle of the crop in Bronkhorstspruit, South Africa, where UAV data collection took over four dates (pre-flowering, flowering, grain filling, and maturity). The five spectral bands (red, green, blue, near-infrared, and red-edge) of the UAV data, vegetation indices, and grey-level co-occurrence matrix textural features were computed from the bands. Feature selection relied on the correlation between these features and the measured maize yield to estimate maize yield at each growth period. Crop yield prediction was then conducted using our machine learning (ML) regression models, including Random Forest, Gradient Boosting (GradBoost), Categorical Boosting, and Extreme Gradient Boosting. The GradBoost regression showed the best overall model accuracy with R2 ranging from 0.05 to 0.67 and root mean square error from 1.93 to 2.9 t/ha. The yield variability across the growing season indicated that overall higher yield values were predicted in the grain-filling and mature growth stages for both maize fields. An analysis of variance using Welch’s test indicated statistically significant differences in maize yields from the pre-flowering to mature growing stages of the crop (p-value < 0.01). These findings show the utility of UAV data and advanced modelling in detecting yield variations across space and time within smallholder farming environments. Assessing the spatiotemporal variability of maize yields in such environments accurately and timely improves decision-making, essential for ensuring sustainable crop production.

Nano molybdenum trioxide-mediated enhancement of soybean yield through improvement of rhizosphere soil molybdenum bioavailability for nitrogen-fixing microbial recruitment

Molybdenum (Mo) plays a pivotal role in the growth and nitrogen-fixing process of plants mediated by rhizobia. However, the influence of nano‑molybdenum trioxide (MoO3NPs) on soybean growth, rhizosphere bioavailable Mo, and nitrogen-fixing microorganisms remains underexplored. Here, we report that compared with that of ionic Mo and bulk MoO3, the utilization of MoO3NPs (specifically NPs0.05 and NPs0.15) significantly boosted the available Mo content in the rhizosphere soil throughout the seedling (by 21.64 %–101.38 %), podding (by 54.44 %–68.89 %), and mature stage (by 34.41 %–to 45.71 %) of soybean growth. Furthermore, both NPs0.05 and NPs0.15 treatments maintained consistently higher levels of acid-extractable Mo, reducible Mo, and oxidizable Mo across these stages, which facilitated stable conversion and supply of bioavailable Mo. Within the rhizosphere soil, NPs0.05 and NPs0.15 treatments resulted in the highest relative abundance of Rhizobiales and Bradyrhizobium genera, and significantly promoted the colonization of nitrogen-fixing microorganisms, thereby increasing the content of nitrate nitrogen (NO3−-N) by 8.69 % and 7.72 % and ammonium nitrogen (NH4+-N) by 44.75 % and 17.55 %, respectively. Ultimately, these effects together contributed to 107.17 % and 84.00 % increment in soybean yield by NPs0.05 and NPs0.15 treatments, respectively. In summary, our findings underscore the potential of employing MoO3NPs to promote plant growth and maintain soil nitrogen cycling, indicating distinct advantages of MoO3NPs over ionic Mo and bulk MoO3.

The effects of pre-harvest glyphosate rate and timing on yield and pre-malt quality of malting barley

The production of barley cultivars with malting and brewing quality characteristics is subject to strict grading and technical standards for the end-use market. Environmental and management factors can significantly alter grain quality, and the qualities required for malting. Crop and kernel uniformity are critical factors where variability can exceed the tolerance for meeting malt quality. A practice to address variations in crop maturity is the application of pre-harvest glyphosate. Pre-harvest glyphosate applications can, however, alter malting characteristics in barley, and, if mis-timed, can also reduce yield. A 4-year study at five locations in Alberta and Saskatchewan from 2013 to 2017 was conducted to determine the effects of pre-harvest glyphosate applications on malting barley characteristics. Glyphosate was applied at 900 and 1125 g ae ha−1 on malting barley cultivars ‘CDC Meredith’ and ‘AC Metcalfe’ malting barley at soft dough, hard dough, and physiological maturity growth stages. Yield reductions of up to 12% were observed from glyphosate applications at soft dough, and yield was maximized with applications at physiological maturity. Glyphosate application, at two rates, reduced percentage plump kernels, but did not affect kernel weight or protein concentration. The growth stage of barley plants did not provide an accurate indicator of seed moisture levels at the time of application, which motivated our conclusion that glyphosate applications can be mistimed by inaccurate indicators. The results motivate our questioning of the utility of pre-harvest glyphosate applications, given the adverse effects to barley yield and quality observed, even when applied according to the label instructions.

Integrating plant morphological traits with remote-sensed multispectral imageries for accurate corn grain yield prediction.

Sustainable crop production requires adequate and efficient management practices to reduce the negative environmental impacts of excessive nitrogen (N) fertilization. Remote sensing has gained traction as a low-cost and time-efficient tool for monitoring and managing cropping systems. In this study, vegetation indices (VIs) obtained from an unmanned aerial vehicle (UAV) were used to detect corn (Zea mays L.) response to varying N rates (ranging from 0 to 208 kg N ha-1) and fertilizer application methods (liquid urea ammonium nitrate (UAN), urea side-dressing and slow-release fertilizer). Four VIs were evaluated at three different growth stages of corn (V6, R3, and physiological maturity) along with morphological traits including plant height and leaf chlorophyll content (SPAD) to determine their predictive capability for corn yield. Our results show no differences in grain yield (average 13.2 Mg ha-1) between furrow-applied slow-release fertilizer at ≥156 kg N ha-1 and 208 kg N ha-1 side-dressed urea. Early season remote-sensed VIs and morphological data collected at V6 were least effective for grain yield prediction. Moreover, multivariate grain yield prediction was more accurate than univariate. Late-season measurements at the R3 and mature growth stages using a combination of normalized difference vegetation index (NDVI) and green normalized difference vegetation index (GNDVI) in a multilinear regression model showed effective prediction for corn yield. Additionally, a combination of NDVI and normalized difference red edge index (NDRE) in a multi-exponential regression model also demonstrated good prediction capabilities.

SULTR2;1 Adjusts the Bolting Timing by Transporting Sulfate from Rosette Leaves to the Primary Stem.

Sulfur (S) is an essential macronutrient for plant growth and metabolism. SULTR2;1 is a low-affinity sulfate transporter facilitating the long-distance transport of sulfate in Arabidopsis. The physiological function of SULTR2;1 in the plant life cycle still needs to be determined. Therefore, we analyzed the sulfate transport, S-containing metabolite accumulation and plant growth using Arabidopsis SULTR2;1 disruption lines, sultr2;1-1 and sultr2;1-2, from seedling to mature growth stages to clarify the metabolic and physiological roles of SULTR2;1. We observed that sulfate distribution to the stems was affected in sultr2;1 mutants, resulting in decreased levels of sulfate, cysteine, glutathione (GSH) and total S in the stems, flowers and siliques; however, the GSH levels increased in the rosette leaves. This suggested the essential role of SULTR2;1 in sulfate transport from rosette leaves to the primary stem. In addition, sultr2;1 mutants unexpectedly bolted earlier than the wild-type without affecting the plant biomass. Correlation between GSH levels in rosette leaves and the bolting timing suggested that the rosette leaf GSH levels or limited sulfate transport to the early stem can trigger bolting. Overall, this study demonstrated the critical roles of SULTR2;1 in maintaining the S metabolite levels in the aerial part and transitioning from the vegetative to the reproductive growth phase.

Candidate genes controlling alkaline-saline tolerance in two different growing stages of wheat life cycle

BackgroundAlkaline-saline (AS) stress threats crop development and productivity. Understanding the genetic control of AS tolerance in wheat is important to produce wheat cultivars that outstand such a severe stress condition.MethodsA set of 48 cultivars were tested under controlled and AS stress conditions at seedling and maturity stages. The effect of AS on seedlings and kernel traits was measured to select tolerant and high-yielding genotypes. Single-marker-analysis (SMA) and gene enrichment were conducted to understand the genetic control of AS tolerance in both growth stages.ResultsAS stress decreased all kernel traits and most of the seedling traits. High correlations were found between the studied traits in each growth stage. The correlation between the traits related to both stages was non-significant. SMA identified a total of 292 and 52 markers significantly associated with the studied traits under controlled and AS stress conditions. Seven and 20 gene models were identified to control AS tolerance in each stage. Gene enrichment analysis identified one and six networks that control AS tolerance. Four genotypes were selected as superior genotypes.ConclusionThe genetic control of the studied traits differs under control and AS conditions. Two genetic systems control AS tolerance in each growth stage. This study is the first one that unlocked the genetic control of AS tolerance in seedling and mature growth stages and identified the biological process that lead to this tolerance. Four genotypes were selected for crossing in future breeding programs to improve AS tolerance in spring wheat.

Allelopathic Potential of Parthenium hysterophorus: Is it Growth-stage Dependent?

World’s one of the most invasive weeds Parthenium hysterophorus L. (Congress grass, family Asteraceae), native to South America, is the most aggressive alien weed in India. The present study aimed to determine the growth stage (early, intermediate and mature) of this weed which was most detrimental to the growth of adjoining crop plants. Impacts of leaf-leachate concentrations (0.5%, 1% and 2%) prepared from leaves at different growth stages of P. hysterophorus were investigated on seed germination and growth of crop Vigna unguiculata. The germination percentage, shoot length, number of leaves, pods, seeds and total biomass of the crop plants significantly declined with increasing concentration of the Parthenium leaf-leachate (maximum at 2%w/v) at all growth stages. However, the leaf-leachate from the leaves of P. hysterophorus at the early growth stage showed the highest detrimental impact on the crop V. unguiculata, followed by intermediate and mature growth stages. Total phenolic content, antioxidant activity and enzymatic were highest in leaves of P. hysterophorus at the early growth stage. In conclusion, the early growth stage of this noxious weed evidently being most detrimental to the growth of adjoining crop plants, suggests Parthenium’s early growth-centric management implication.

Influence of planting pattern on peanut ecosystem daytime net carbon uptake, evapotranspiration, and water-use efficiency using the eddy-covariance method

Peanut is planted in a pattern of either single or twin rows in Georgia, USA. However, limited attention has been paid to the impact of planting pattern on the carbon footprint and how the net carbon uptake is intertwined with the amount of water used to determine the ecosystem water-use efficiency (WUE) in peanut. This paper reports on the relationship between the amount of carbon produced to the amount of water used in peanut, carbon dioxide flux, and crop evapotranspiration of peanut in a single- or in a twin-row planting pattern measured using the eddy-covariance method. To the best of our knowledge, the present study is unique in that it examines for the first time the effect of planting pattern on the net carbon uptake and WUE. The two-year study took place in contrasting weather conditions with the 2016 year experiencing a higher vapor pressure deficit and lower precipitation than in the 2018 year. In this study, field-scale daytime net carbon ecosystem exchange (CO2 fluxes), ET and WUE of single- and twin-row peanut were compared using the eddy-covariance technique. Results showed that in 2018, both the net carbon uptake from the atmosphere and the WUE of twin-row peanut were significantly greater than those in the single-row peanut by 7-10% and ~9% respectively, for pod filling and seed maturity growth stages (aGDD 1000-2000 and aGDD > 2000). In 2016, the net daytime carbon uptake and WUE of peanut were similar for both planting patterns during pod filling (aGDD 1000-2000). Higher precipitation and lower VPD in 2018 likely resulted in greater peanut yield in twin-row as compared to single-row with abundant precipitation. Owing to the fast canopy growth rate in twin-row peanut, results suggest that during the vegetative stage (aGDD<500) in 2016, both daytime net carbon uptake from the atmosphere and WUE were considerably greater in twin-row than single-row by 32% and 27%, respectively. Given that in both years, the ET from both planting patterns was similar, it appears that the determination of WUE in both planting patterns was more impacted by changes in daytime net carbon uptake than evapotranspiration. The results of this study suggest the possibility that the higher WUE at the critical stages of twin-row peanut in 2018 are likely to lead to greater yield than single-row peanut. This should be confirmed with further year-to-year investigations.

Soybean and Cotton Spermosphere Soil Microbiome Shows Dominance of Soilborne Copiotrophs.

The spermosphere is the transient, immediate zone of soil around imbibing and germinating seeds. It represents a habitat where there is contact between seed-associated microbes and soil microbes, but it is studied less than other plant habitats. Previous studies on spermosphere microbiology were primarily culture based or did not sample the spermosphere soil as initially defined in space and time. Thus, the objectives of this study were to develop an efficient strategy to collect spermosphere soils around imbibing soybean and cotton in nonsterile soil and investigate changes in microbial communities. The method employed sufficiently collected spermosphere soil as initially defined in space by constraining the soil sampled with a cork borer and confining the soil to a 12-well microtiter plate. Spermosphere prokaryote composition changed over time and depended on the crop within 6 h after seeds were sown. By 12 to 18 h, crops had unique microbial communities in spermosphere soils. Prokaryote evenness dropped following seed imbibition, with the proliferation of copiotrophic soil bacteria. Due to their long history of plant growth promotion, prokaryote operational taxonomic units (OTUs) in Bacillus, Paenibacillus, Burkholderia, Massilia, Azospirillum, and Pseudomonas were notable organisms enriched. Fungi and prokaryotes were hub taxa in cotton and soybean spermosphere networks. Additionally, the enriched taxa were not hubs in networks, suggesting that other taxa besides those enriched may be important for spermosphere communities. Overall, this study advances knowledge in the assembly of the plant microbiome early in a plant's life, which may have plant health implications in more mature plant growth stages. IMPORTANCE The central hypothesis of this research was that plant species and seed exudate release would alter the assembly of microbes in the spermosphere soil. Our research investigated the response of microbes to the initial burst of nutrients into the spermosphere soil, filling knowledge gaps from previous studies that pregerminated seeds under sterile conditions. We identified several copiotrophic bacterial lineages with a long history of plant growth promotion proliferating in response to the initial exudate release. With a comparative network approach, we show that these copiotrophic bacteria are not central to networks, demonstrating that other microbes (including fungi) may be important for community structure. This study improves knowledge on microbial dynamics in the understudied spermosphere and helps inform solutions for biologically or ecologically motivated solutions to spermosphere pathogens.

Waterlogging stress reduces cowpea (Vigna unguiculata L.) genotypes growth, seed yield, and quality at different growth stages: Implications for developing tolerant cultivars under field conditions

Waterlogging is a significant abiotic stress that reduces the oxygen supply to roots in the rhizosphere, impairing plant growth and development. Cowpea is highly sensitive to waterlogging, and their grain yield is affected by genotype and growth stage. Understanding the growth and physiological responses of cowpea to waterlogging stress is crucial for developing strategies to improve crop yield in waterlogged environments. In this two-year field trial, we quantified the impact of ten days of waterlogging on morpho-physiological attributes, seed yield components, and seed quality of two cowpea genotypes (UCR 369 and EpicSelect.4) at different growth stages. Waterlogging during the reproductive (R2) growth stage had the most substantial impact on cowpea, with an average reduction of leaf area by 65%, chlorophyll content by 39%, stomatal conductance (gs) by 93%, and photochemical efficiency by 32% compared to non-waterlogged plants. These effects were less pronounced during the vegetative (V4) and physiological maturity (R7) growth stages. Lower photosynthetic capacity resulted in reduction of biomass accumulation, pod dry weight, number of pods per plant, and seed weight under waterlogging. EpicSelect.4 was more sensitive to waterlogging at the R2 stage, showing a greater reduction in seed yield (58%) compared to UCR 369 (46%). Additionally, UCR 369 maintained seed protein content under waterlogging conditions, while it decreased by 8% in EpicSelect.4 seeds. Overall, UCR 369 was more tolerant to waterlogging stress than EpicSelect.4, with the most apparent effect of waterlogging on yields occurring at the R2 stage due to the high energy demands of the cowpea reproductive process. Our study highlights the importance of selecting cowpea genotypes with greater tolerance to waterlogging stress during the reproductive stage to mitigate the negative effects of waterlogging on seed yield in flood-prone environments. These results provide valuable insights into the mechanisms of cowpea's responses to waterlogging stress and can aid in developing strategies for improving cowpea yield in waterlogged environments, which are expected to become more frequent due to climate change.

Open innovation strategy and performance of SMEs in the IT industry located in Korea’s innovation clusters: the role of government subsidies

ABSTRACT This study examines the effect of small and medium-sized enterprises (SMEs)’ open innovation activities on performance, depending on the growth stage. It also studies the mediating effect of government subsidies on SMEs’ innovation performance. We collected data from 452 SMEs in the information technology (IT) industry located in Korea’s innovation clusters. The findings show that SMEs’ absorptive capacity and external network activities positively influence their performance, with stronger effects for SMEs in their mature growth stage. Moreover, a higher ratio of government subsidies in R&D investment positively mediates the relationship between external network activities and innovation performance. This study presents several implications for policymakers to support SMEs’ R&D activities using government subsidies.

The Influence of Aerated Irrigation on the Evolution of Dissolved Organic Matter Based on Three-Dimensional Fluorescence Spectrum

In order to unravel the effect of aerated irrigation on soil dissolved organic matter (DOM) fluorescence characteristics, and humification degree, a randomized block experiment was conducted with three factors and a two-level design, i.e., two irrigation rates (0.6 and 1.0 times of crop evaporation pan coefficient, W1 and W2), two nitrogen application rates (225 and 300 kg hm−2, N1 and N2), and two aeration rates (15% and 0% in control treatment, A1 and A0). Fluorescence regional integration (FRI) and correlation analysis methods were used to investigate the evolution characteristics of the soil DOM fluorescence spectrum. Under aerated and conventional subsurface irrigation, soil DOM components were dominated by humic acid-like substances, fulvic acid-like substances, tryptophan-like proteins, and supplemented by tyrosine-like proteins and dissolved microbial metabolites. Soil aeration could promote the consumption of soil DOM components under low irrigation rates and accelerate the consumption of soil DOM components under high irrigation rates. The humification index of AI treatments varied from 8.47 to 9.94 during the maturity growth stage of pepper, averagely increased by 31.59% compared with the non-aeration treatment. To sum up, aerated irrigation can promote the depletion of small molecular proteins and accelerate nutrient turnover and the accumulation of big molecular proteins.

Evaluation of time-series Sentinel-2 images for early estimation of rice yields in south-west of Iran

PurposeIn the past three decades, remote sensing-based models for estimating crop yield have addressed critical problems of general food security, as the unavailability of grains such as rice creates serious worldwide food insecurity problems. The main purpose of this study was to compare the potential of time-series Landsat-8 and Sentinel-2 data to predict rice yield several weeks before harvest on a regional scale.Design/methodology/approachTo this end, the sum of normalized difference vegetation index (NDVI)-based models created the best agreement with actual yield data at the golden time window of six weeks before harvest when rice grains were in milky and mature growth stages. The application of nine other vegetation indicators was also investigated in the golden time window in comparison to NDVI.FindingsThe findings of this study demonstrate the viability of identifying locations with poor and superior performance in terms of production management approaches through a rapid and economical solution for early rice grain yield assessment. Results indicated that while some of those, such as enhanced vegetation index (EVI) and optimized soil adjusted vegetation index, were able to estimate rice yield with high accuracy, NDVI is still the best indicator to predict rice yield before harvest. However, experiments can be conducted in different regions in future studies to evaluate the generalizability of the approach.Originality/valueTo achieve this objective, the authors considered the following purposes: using Sentinel-2 time-series data, determining the appropriate growth stage for estimating rice yield and evaluating different vegetation indices for estimating rice yield.

Predviđanje prinosa paradajza i potrošnje vode po scenariju sa deficitom navodnjavanja upotrebom modela AquaCrop, u Afaki, Kaduna, Nigerija

Improving water productivity through deficit irrigation has become a major goal for sustainable agriculture amidst global decline in water availability. The study evaluated the yield, crop water use and water productivities of field-grown drip-irrigated tomato in response to regulated deficit irrigation, and subsequent simulation under different deficit and irrigation method scenarios, using AquaCrop model, in Afaka, Nigeria. The field experiment, laid in randomized complete block design, comprised three deficit irrigation levels (80, 60 and 40% of reference evapotranspiration, ETo) imposed at the vegetative, flowering and maturity growth stages, with 100% ETo at the three crop growth stages as the control. The highest fresh fruit yield (19.0 t/ha) was obtained irrigating with 100% ETo value at all growth stages but the highest water productivity of fresh fruit (4.94 kg/m3 ) was obtained irrigating with 60% ETo at maturity stage, then full irrigation at vegetative and flowering stages. On fruit dry yield basis, the highest simulated crop water productivity (0.46 kg/m3 ) for the deficit scenarios was obtained irrigating with 80% ETo at all the three growth stages, having the highest fruit dry yield (1.67 t/ha) and the lowest seasonal water applied (447 mm). Under the scenarios of irrigation methods (drip, basin and furrow), the fruit dry yield was similar in each treatment, but water productivity was highest (0.53 kg/m3 ) under drip irrigation system. Irrigating with 80% ETo at all the entire crop growth cycle of UC 82B tomato is recommended for the highest crop water productivity.

Overexpression of a rice Tubby-like protein-encoding gene, OsFBT4, confers tolerance to abiotic stresses.

The OsFBT4 belongs to a small sub-class of rice F-box proteins called TLPs (Tubby-like proteins) containing the conserved N-terminal F-box domain and a C-terminal Tubby domain. These proteins have largely been implicated in both abiotic and biotic stress responses, besides developmental roles in plants. Here, we investigated the role of OsFBT4 in abiotic stress signalling. The OsFBT4 transcript was strongly upregulated in response to different abiotic stresses in rice, including exogenous ABA. When ectopically expressed, in Arabidopsis, under a constitutive CaMV 35S promoter, the overexpression (OE) caused hypersensitivity to most abiotic stresses, including ABA, during seed germination and early seedling growth. At the 5-day-old seedling growth stage, the OE conferred tolerance to all abiotic stresses. The OE lines displayed significant tolerance to salinity and water deficit at the mature growth stage. The stomatal size and density were seen to be altered in the OE lines, accompanied by hypersensitivity to ABA and hydrogen peroxide (H2O2) and a reduced water loss rate. Overexpression of OsFBT4 caused upregulation of several ABA-regulated/independent stress-responsive genes at more advanced stages of growth, showing wide and intricate roles played by OsFBT4 in stress signalling. The OsFBT4 showed interaction with several OSKs (Oryza SKP1 proteins) and localized to the plasma membrane (PM). The protein translocates to the nucleus, in response to oxidative and osmotic stresses, but failed to show transactivation activity in the yeast system. The OE lines also displayed morphological deviations from the wild-type (WT) plants, suggesting a role of the gene also in plant development.

Effect of Sodium Chloride Salt on Germination, Growth, and Elemental Composition of Alfalfa Cultivars with Different Tolerances to Salinity

The aim of this study was to evaluate physiological responses and elemental composition of three salt tolerant alfalfa (Medicagosativa L.) cultivars, ‘Halo’, ‘Bridgeview’, ‘Rugged’, and two intolerant cultivars ‘Rangelander’ and ‘Vernal’ under five salinity levels (0 dSm−1, 4 dSm−1, 8 dSm−1, 12 dSm−1 and 16 dSm−1) in a sand based hydroponic system in the greenhouse. The germination percentage among the cultivars was highest for ‘Halo’ under salt stress. ‘Rugged’ and ‘Halo’ had higher seed vigor than the other cultivars in 16 dSm−1 EC. Among the alfalfa cultivars, ‘Rugged’ had the highest chlorophyll content at 0–12 dSm−1 EC. There was variation for root (p = 0.01) and shoot (p = 0.03) biomass among the alfalfa cultivars. Salt stress reduced (p < 0.001) plant height and shoot biomass, with 4.2% and 7.9% reduction for each 1 dS m−1 increase, respectively. Shoot biomass showed a positive correlation with plant height (p < 0.001, r = 0.80), chlorophyll content (p < 0.001, r = 0.56), root biomass (p < 0.001, r = 0.51), but was not correlated with seed vigor. This study demonstrated that seed vigor in the germination stage can not be used to predict salt tolerance of alfalfa at mature growth stages, however plant height and leaf chlorophyll content can serve as physiological markers for high shoot biomass selection at mature growth stages under salt stress.

Deficit irrigation impacts on greenhouse gas emissions under drip-fertigated maize in the Great Plains of Colorado.

Precise water and fertilizer application can increase crop water productivity and reduce agricultural contributions to greenhouse gas (GHG) emissions. Regulated deficit irrigation (DI) and drip fertigation control the amount, location, and timing of water and nutrient application. Yet, few studies have measured GHG emissions under these practices, especially for maize (Zea mays L.). The objective was to quantify N2 O and CO2 emission from DI and full irrigation (FI) within a drip-fertigated maize system in northeastern Colorado. During two growing seasons of measurement, treatments consisted of mild, moderate, and extreme DI and FI. Deficit irrigation was managed based on growth stage so that full evapotranspiration (ET) was met during the yield-sensitive reproductive stage, but less than full crop ET was applied during the late vegetative and maturation growth stages. In the first year, mild DI (90% ET) reduced N2 O emissions by 50% compared with FI. In the second year, compared with FI, moderate DI (69-80% ET) reduced N2 O emissions by 15%, and extreme DI (54-68% ET) reduced N2 O emissions by 40%. Only extreme DI in the second year significantly reduced CO2 emissions (by 30%) compared with FI. Mild DI reduced yield-scaled emissions in the first year, but moderate and extreme DI had similar yield-scaled emissions as FI in the second year. The surface drip fertigation resulted in total GHG emissions that were one-tenth of literature-based measurements from sprinkler-irrigated maize systems. This study illustrates the potential of DI and drip fertigation to reduce N2 O and CO2 emissions in irrigated cropping systems.

Tyrosine or lysine priming modulated phenolic metabolism and improved cadmium stress tolerance in mung bean (Vigna radiata L.)

Cadmium stress deleteriously affects plant growth and yield with disturbed plant metabolism. Phenylpropanoid pathway (PePP) is an important component of plant secondary metabolism known to produce nutraceutical antioxidants. We hypothesized that tyrosine (Tyr) and lysine (Lys) vary in their metabolic entry into PePP pathway and modulate it differently. Hence, a completely randomized experiment was planned with four replicates; 12 hours primed (control, hydroprimed, 0.2% Tyr, and 0.2% lysine) mungbean seeds with two stress levels (0 and 0.22 mM CdCl2). Harvests were planned at vegetative and fully mature stages of growth. Attributes like total soluble proteins, total phenolic contents, flavonoids, membrane damage characteristics, and phenolic profile were used to compare the efficacy of applications. Cadmium (0.22 mM) reduced growth in terms of leaf dry weight, leaf area, germination percentage, root vigor, shoot vigor, number of pods, and soluble proteins. Enhanced levels of malondialdehyde (MDA) and relative Root Electrolyte Leakage indicated oxidative damage in stressed plants. Other parameters of growth and yield remained ineffective with increased accumulation of phenolics and flavonoids indicative of moderate cadmium tolerance. Lys and Tyr priming improved root fresh weight, shoot length, leaf dry weight, germination percentage, root and shoot vigor, number of pods, soluble proteins, phenolics and flavonoids with reduction of MDA and root electrolyte leakage. Activity of PAL, leaf number and leaf area were exclusively increased in Tyr primed stressed plants. Tyr directly and Lys indirectly affected products of PePP with improved stress tolerance in mung bean.

Effects of nitrogen and water stress on the rehydration, endogenous hormonal regulation and yield of maize

AbstractWater scarcity is known to be a strong limiting factor affecting maize grown and yield in cold semi‐arid regions. Numerous studies have shown that rehydration improves maize growth. Our study aimed to explore the effects of rehydration treatments on maize growth and yield under water and nitrogen stress during different growth stages. We selected the drought‐tolerant maize variety Nendan 19 (ND19) and subjected it to water stress during the V6 (sixth‐leaf), R2 (filling) and R6 (maturity) growth stages and a rehydration treatment after each stress stage. Our results indicated that N1 (N100 kg N ha−1) and N3 (N300 kg N ha−1) treatments significantly increased the leaf moisture status relative to water content (RWC), bound water content (BWC), free water content (FWC) and water potential (WP)) at different growth stages. Similar trends were observed in the accumulation of plant leaf and root hormones (zeatin+zeatin riboside, indole‐3‐acetic acid, abscisic acid and gibberellic acid), photosynthetic pigments and chlorophyll fluorescence. However, under the same water stress conditions, they decreased as the N rate increased and reached a minimum value in the S3 (water stress for N3) treatments. In addition, with growth stage advancement and extension of the rehydration time, both showed a gradual upward trend. The results showed that to save water resources in the cold semi‐arid region, rehydration treatments (R2S1 and R2S3) significantly increased the photosynthetic pigments and chlorophyll fluorescence parameters, leaf moisture status, biomass, 100‐grain weight, hormone content, ear characteristics and grain yield of maize.