Soil Plant Analysis Development Research Articles

Effects of Enzymatic Browning and Leaf Browning Inhibitors on Tobacco

The maturity of fresh tobacco leaves affects the browning of leaves to differing degrees during the curing process, thus affecting the quality of cured tobacco leaves. In this study, tobacco leaves of increasing maturity (M1–M4) were selected. Dark-box experiments were performed to investigate the roasting characteristics and relationship between tobacco leaf maturity and browning and to determine their polyphenol oxidase (PPO) activities and qualities. We found that mature tobacco leaves (M3) had high substance accumulation, and the PPO activity decreased throughout the baking process. After 72 h of curing, the PPO activity in the M3 leaves was 81.22 U/g, which was significantly different from that in M1 and M2. On this basis, three different browning inhibitors (control: 10 mL of distilled water; T1:10 mL of 0.5% citric acid+0.5% polyphenol; and T2:10 mL 0.5% citric acid+0.5% salicylic acid) were sprayed onto the surface of M2 leaves before curing to observe their inhibitory effects. The T2-treated leaves showed inhibited PPO activity, and after baking for 72 h, the peroxidase enzyme (POD) content of the T2-treated leaves was higher, which effectively inhibited the enzymatic reaction. In conclusion, to reduce the browning ratio of tobacco leaves during the curing process, the harvested tobacco leaves should be allowed to reach full maturity when the values of Soil Plant Analysis Development (SPAD) chlorophyll meter ranged 9–13, and 0.5% citric acid+0.5% salicylic acid (T2) should be used as a browning inhibitor to produce tobacco with the highest sensory quality. The results of this study can help inhibit browning and maintaining the quality of the tobacco leaves during the curing process.

Winter wheat SPAD estimation from UAV hyperspectral data using cluster-regression methods

Soil plant analysis development (SPAD) values indicate the relative chlorophyll content in leaves. Chlorophyll plays a vital role in wheat growth and fertilization management as a photosynthetic agent. Unmanned aerial vehicle (UAV) hyperspectral data, combined with measured SPAD values in fields, are widely used to study wheat chlorophyll concentrations over time. In this study, considering the spectral differences in fields with different soil fertility, we propose a new modeling method named as cluster-regression to estimate the winter wheat SPAD at a national soil observation and experimental station in northern Anhui, China. The wheat spectrum was divided into several clusters according to the spectral angular distance, and regression models were built between wheat spectrum and the measured SPAD for each cluster. We used K-means as the clustering method and two types of ensemble learning algorithms, namely, random forests and Extreme Gradient Boosting (XGBoost) as the regression methods. The root-mean-square error (RMSE), median absolute percentage error (MAPE), and R2 were used as model accuracy indicators. The results showed that the XGBoost model slightly outperformed the random forest in wheat SPAD estimation. Coupled with the first step of K-means clustering, the overall performance of the regression models can be easily improved, and cluster-XGBoost showed the best performance, with an RMSE of 1.444, MAPE of 2.36%, and R2 of 0.925. Moreover, addition of soil organic matter and soil total nitrogen positively impacted the accuracy of SPAD estimation models. This study provides an effective UAV hyperspectral technique for wheat SPAD concentration estimation and demonstrates the impact of soil organic matter and total nitrogen on wheat SPAD estimation.

Effects of temperatures on growth, physiological, and antioxidant characteristics in Houttuynia cordata

Houttuynia cordata Thunb. (HC) is a traditional medicinal plant with a variety of pharmaceutical activities. The objective of this study was to investigate the growth, photosynthetic parameters, and antioxidant properties of HC plants in response to various temperatures. Pots of HC plants were maintained in day/night temperatures of 15/10 °C, 20/15 °C, 25/20 °C (control), 30/25 °C, and 35/30 °C for two months in each of five growth chambers having a 13.5 h photoperiod at 396, 432, 474, 449, and 619 µmol·m-2·s-1 radiation, respectively. Eight plants for each temperature were randomly placed in a growth chamber. HC plants survived at 30/25 °C and 35/30 °C treatments and had significantly higher plant heights, leaf numbers, and soil-plant analysis development (SPAD) and normalized difference vegetation index (NDVI) values compared to other treatments. However, long-term 35/30 °C treatment caused reductions in leaf length and width, significantly decreasing shoot and leaf fresh weight (FW) and dry weight (DW) compared to 30/25 °C treatment and controls. These results indicate that HC leaf development was affected during the 35/30 °C treatment, and that both SPAD and NDVI can help in advancing our understanding of the photosynthesis process in HC. Moreover, all plants subjected to 15/10 °C suffered more severely in all traits and parameters than other treatments. Therefore, HC plants tended to be heat-tolerant and exhibited adaptive morphologic plasticity to 30/25 °C conditions. Positive and significant correlations were observed among temperatures and total phenolics (TP), total flavonoids (TF), chlorogenic acid (CGA), and hyperoside (HO) content, and all bioactive contents increased as temperature increased, except that both CGA and HO content were remarkably decreased after 30/25 °C treatment. Thus, 30/25 °C treatment would be more beneficial for high marketability resulting from increased leaf number, DW, and all secondary metabolites compared to other treatments, and for use as a health food and for medicinal purposes. In addition, leaf growth, physiological parameters, and secondary metabolite accumulations in HC plants can be optimized for commercial production via temperature control technologies. This approach may also be applicable to leafy vegetables to produce stable industrial supplies having high leaf yields and metabolite content.

Producción de plántulas de chile habanero con fertilización orgánica y biológica

Chemical fertilization needs to be replaced in cultivation systems. Thus, this study proposes the alternative of combining compost with liquid organic fertilizers and biofertilizers to obtain habanero pepper seedling quality. The objective is to evaluate two liquid organic fertilizers in combination with Purpureocillium lilacinum and Beauveria brongniartii in growth, nutritional concentration and quality of habanero pepper seedlings grown in peat moss/compost substrate to substitute chemistry fertilization. A completely randomized experimental design was used with a bifactorial arrangement: (1) liquid organic fertilizers (vermicompost leachate and the commercial product Pez Terra®, diluted in water in a 1:200 ratio); (2) biofertilizers (B. brongniartii and P. lilacinum) and a control (25% Steiner’s nutrient solution) group were also evaluated. The seedlings treated with the commercial product increased their growth, Soil Plant Analysis Development (SPAD) units, N, P and K concentrations, and quality with P. lilacinum inoculation; seedling height, stem diameter, leaf area, N concentration and slenderness index increased, with respect to B. brongniartii. The interaction of the commercial fertilizer and P. lilacinum, and use of peat moss/compost substrate 1:1 (v/v) increased seedling height by 10%, leaf area by 35%, N and P concentrations by 57% and 35%, respectively, and slenderness index by 8% compared to the seedlings that were produced with Steiner’s 25% nutrient solution and peat moss. Therefore, this combination was considered viable for the production of habanero pepper seedlings and may substitute chemistry fertilization.

Analysis of the relationship between leaf color spectrum and soil plant analysis development

Assessment nutrient content of maize leaf is particularly important in achieving higher grain yield. Characterization of leaf chlorophyll involves routine Soil Plant Analyzer Development (SPAD) reading particularly at critical stage of growth development. The objective of the study was to assess the color spectrum of maize leaf in relation to the chlorophyll content by using Random-forest modeling. genotypes of corn plants based on the characters of the ear and kernel using a logistic regression model. The research was conducted at IP2TP Bajeng in 2021 by planting maize varieties at various fertilizer level. RGB data of maize leaf was recorded by using Hamamatsu sensor (Hamamatsu, Japan), and converted to HIS, HSV and LAB color spectrum. The results indicated that Random-forest model with 20-fold validation indicated the highest accuracy as compared to the other fold-range. Among the tested model, integration of Random-forest model to LAB (Light, red/green coordinate, and the yellow/blue coordinate) color spectrum provided the best model performances with RMSE (4.77), MSE (22.76), MAE (3.80) and R2 (0.853). This value indicates that the use of Hamamatsu color sensor and converted into LAB color spectrum provided the best SPAD (Soil Plant Analyzer Development) reading with high accuracy and consistency of results. Thus, digital based model can be integrated with manual selection for fast and precise nutrient monitoring.

Monitoring Optical Tool to Determine the Chlorophyll Concentration in Ornamental Plants

The accurate estimation of leaf photosynthetic pigments concentration is crucial to check the plant´s health. Traditional methods of measuring photosynthetic pigments involve complex procedures of solvent extraction followed by spectrophotometric determinations. Portable plant instruments such as Soil Plant Analysis Development (SPAD) meters can facilitate this task for the speed and simplicity of the measures. The relationship between chlorophyll index obtained by SPAD-502 and pigment concentration in several ornamental species can help in the management of ornamental plant production. Two trials have been carried out in two different growing seasons (spring and summer) and facilities (greenhouse and open air), involving 30 ornamental species. There was a high linear relationship between concentrations of Chla and Chlb, as well as between Chlt and Ct in different species studied under greenhouse and open field conditions. The ratio between Chla and Chlb was higher at open field conditions and similar between Chlt and Ct. There was also a good relationship between Chlorophyll index and Chlt under both growing conditions, as well as between Chlorophyll index and Ct under greenhouse conditions. However, linear relationships with different slopes were observed for groups of species at open field conditions.

Whole-plant compensatory responses of isoprene emission from hybrid poplar seedlings exposed to elevated ozone

It is still unclear whether the responses of isoprene (ISO) emission to elevated O3 vary with biological organization level (i.e. leaf and whole-plant). To study such responses and the possible reasons explaining their variation, we investigated the effect of O3 (CF: charcoal-filtered ambient air; E-O3: non-filtered ambient air enriched with O3) on ISO emission rate (ISOrate), net photosynthetic rate (Pn), leaf nitrogen and carbon contents, and leaf growth traits in poplar seedlings (Populus deltoides cv. 55/56 × P. deltoides cv. Imperial) during one growing season. Opposite effects of E-O3 on Pn were found between upper leaves (positive effect) and lower leaves (negative effect). Compared to CF, E-O3 significantly decreased leaf mass per area, number of leaves, and leaf biomass, but increased leaf nitrogen content and individual leaf size. In the framework of such compensatory responses, poplar seedlings further increased ISOrate in upper leaves and decreased ISOrate in lower leaves, thus preventing significant decrease in the overall whole-plant ISOrate by E-O3. The measured whole-plant ISOrate also showed that the simplistic estimation approaches based on the linear regression between chlorophyll content indicated by soil plant analysis development meter (SPAD value) and leaf-level ISOrate could not accurately reflect the true response of whole plant to elevated O3. For more accurate predictions, the potential ISO compensatory response to increasing O3 concentration should be incorporated into the climate biogeochemical models related to ISO emission.

Protective Effects of Salicylic Acid and Calcium Chloride on Sage Plants (Salvia officinalis L. and Salviaelegans Vahl) under High-Temperature Stress.

High-temperature stress is a major risk to fresh-market Salvia production, and heat intolerance is a major constraint in sage cultivation, particularly during the hot summer season. Previously, we investigated heat tolerance in five common-market cultivars of sage plants using leaf relative injury (RI) values and found that S. elegans Vahl (SE) and S. officinalis L. (SO) were the most and least heat-tolerant species, respectively. The exogenous applications of salicylic acid (SA) and calcium chloride (CaCl2) to alleviate heat stress in various species have been extensively studied, but reports of the effects of SA and CaCl2 treatments on the heat tolerance of sage plants are scarce. The objective of this study was to investigate how SA and CaCl2 affect the physiology and morphology of SE and SO plants under high-temperature conditions. Potted plants were pretreated with SA (0, 100, 200, 400, and 800 μM) and CaCl2 (0, 5, 10, and 15 mM), alone and combined, exposed to 55 °C and 80% humidity for 30 min, then placed in an environment-controlled chamber at 30 °C for three days and evaluated for changes in phenotypic appearance, RI, spectral reflectance, and chlorophyll fluorescence indices at different time intervals. Plants watered without chemical solutions were used as controls. Our results show that the growth of SO plants pretreated with SA and CaCl2 was more robust, compared with control plants, which were considerably affected by heat stress, resulting in brown, withered leaves and defoliation. The effects of the combined applications of SA (100 μM) and CaCl2 (5 mM) to SO plants were superior to control plants in increasing values of soil-plant analysis development (SPAD), normalized difference vegetation index (NDVI), and the maximal quantum yield of photosystemII photochemistry (Fv/Fm), while reducing RI%. Furthermore, SO plants exhibited higher SPAD and Fv/Fm values and lower RI% than SE plants in combined treatments at all time intervals after heat stress, implying that different genotypes displayed variations in their SPAD, Fv/Fm, and RI%. Thus, a combined treatment of 100 μM of SA and 5 mM of CaCl2 is effective and beneficial to plant appearance and ability to ameliorate heat stress. These indices can be used as indicators to characterize the physiology of these plants and applied on a commercial scale for informing the development of rapid and precise management practices on bedded sage plants grown in plant factories to achieve maximum market benefit.

Development of a low-cost portable device for pixel-wise leaf SPAD estimation and blade-level SPAD distribution visualization using color sensing

Soil Plant Analysis Development (SPAD) was proved as a reliable indicator for the representation of leaf chlorophyll or nitrogen content. Portable plant SPAD sensors have been widely studied to determine plant nitrogen status rapidly in recent years. However, the SPAD-502 device could only measure a single point in one shot, and its price was high. Moreover, most of the presented DIY devices for SPAD evaluation required clamping operation to get the transmitted light signal using complex hardware architecture. In this study, an ultra-portable SPAD evaluation system, defined as SPAD-Cap, was proposed for leaf SPAD distribution analysis. The RGB camera module, Raspberry Pi Zero, and light source were integrated. Two modeling methods, including partial least square regression (PLSR) and convolutional neural network for regression (CNN-R), were used to evaluate pixel-level SPAD value based on the color features of the corresponding pixel. The SPAD distribution map was generated by traversing all pixels of the tested blade sample using the trained model. A Web GUI was developed for controlling the whole system and accessing the visualization result. The testing result showed that the designed SPAD-Cap achieved R2 of 0.97 and RMSE of 2.5 SPAD units to inspect rape leaf SPAD. For leaves in several species, R2 was 0.91, and RMSE was about 4.0 SPAD. Moreover, all the processing steps, including data collection, processing, storage, and visualization, were involved in the SPAD-Cap system, which could be a potential solution for rapid and automatic inspection of leaf SPAD distribution.

Performance of Hybrid Wheat Cultivars Facing Deficit Irrigation under Semi-Arid Climate in Pakistan

Predicted decrease in water availability for crop production and uncertainty in climatic conditions require devising the irrigation strategies to increase water use efficiency (WUE) for sustainable crop production. The development of crop cultivars with higher WUE is a pre-requisite for such strategies, particularly in developing countries, including Pakistan, who face stern food security challenges. A two-year field study was conducted following a split-plot randomized complete block design to understand the effects of wheat cultivars (hybrid cultivars, 18A-1 and 18A-2, and local cultivar Ghaneemat IBGE-2016), sowing dates (15th November, 30th November, and 15th December), and irrigation regimes [I (103 mm), II (175 mm), III (254 mm), and IV (330 mm)] at four different growth stages of tillering, booting, anthesis and grain filling on wheat productivity, biomass production and grain yield, and crop-water relations. Early sown hybrid cultivars 18A-1 and 18A-2 showed significantly higher biological and grain yields compared to the local cultivar (59% and 69% higher than the local cultivar). Trends in biomass production and grain yield were also similar at later sowing dates of 30th November and 15th December. However, biological and grain yields decreased with delay in sowing for each cultivar. The data also revealed that hybrid cultivars were better suited to deficient irrigation and generally produced significantly higher biological and grain yields under each moisture regime. Cultivars, sowing dates, and irrigation regime differed significantly for their effects on the Soil Plant Analysis Development (SPAD) values, chlorophyll a and b contents but not for carotenoids. Sowing dates and irrigation regimes had significant effects on relative water content (RWC), water saturation deficit (WSD), water uptake capacity (WUC), and water retention capacity (WRC); however, only WUC varied significantly between the cultivars. The phenological data show that hybrid cultivars took more days to maturity and grain filling than the local cultivar, and days decreased with delayed sowing. The biological and grain yields show significant positive correlations with SPAD values (p < 0.001) and days to maturity (p < 0.001). Our study shows that hybrid wheat cultivars can be opted for higher biomass production and grain yields under deficit irrigation scenarios of semi-arid climatic conditions in Pakistan. Moreover, the hybrid wheat cultivars can perform better than the indigenous cultivar even for delayed sowing dates of 30th November and 15th December.

Physiological and biochemical response of safflower (Carthamus tinctorius L.) cultivars to zinc application under drought stress

Drought is one of the major environmental stresses affecting the many crops performance by altering physiological and biochemical processes. Zinc application could mitigate the adverse effects of drought stress. To investigate the effects of foliar application of zinc on the morphophysiological and biochemical traits of safflower cultivars under drought stress, two field experiments were conducted as split plots based on randomized complete blocks design with three replicates during 2018−2019 and 2019−2020 growing seasons. Experimental factors included drought stress as the primary factor, safflower cultivars, and zinc foliar application as secondary factors. Drought stress included two levels (non-stress and drought stress); safflower cultivars were Isfahan, Linas, Padideh, Parnian, and Goldasht; foliar application of zinc was in three levels (0, 0.5, and 1 kg ha−1 Zn). Results showed drought stress decreased plant height, 1000-seed weight, seed yield, biological yield, soil plant analysis development (SPAD) chlorophyll index, relative water content (RWC), leaf area index (LAI), oil percentage, oil yield, palmitic acid, linoleic acid. Whereas, drought stress increased proline content, oleic acid, and antioxidant enzyme activity. Maximum plant height (145 cm) and oil percentage (29 %) were observed in Isfahan cultivar, maximum amounts of SPAD index (75.96 %), catalase enzyme (CAT) (0.69 μmol min-1 mg protein-1), proline (5 mM g-1 FW), linoleic acid (76 %), and palmitic acid (7 %) were observed in Goldasht cultivar. Parnian cv. with the highest leaf area (2.98 cm2), RWC (78 %), 1000-seed weight (43 g), seed yield (3514 kg ha-1), biological yield (13,542 kg ha-1), peroxidase enzyme (POX) (2.84 μmol min-1 mg protein-1), water-soluble carbohydrates (WSC) (107 mg g-1 DW), and oil yield (807 kg ha-1) had the highest economic yield among the experimented cultivars. Foliar application of 1 kg ha-1 Zn improved oil yield, RWC, SPAD index, proline content, carbohydrate content, LAI, and CAT and POX activities. Zinc application enhanced drought stress tolerance in different cultivars through improving effects on the antioxidant activity system, proline content, carbohydrate content, RWC, and SPAD index.

Mitigation of High-Temperature Damage by Application of Kaolin and Pinolene on Young Olive Trees (Olea europaea L.): A Preliminary Experiment to Assess Biometric, Eco-Physiological and Nutraceutical Parameters

Various products are used to mitigate the negative effects of abiotic stress in olive trees. The aim of the research was to examine an anti-transpirant product (Vapor Gard®, V) and a kaolin- based product (Manisol, K) effect on the growth of two-year-old olive tree seedlings under high temperature. The study was conducted in a greenhouse on trees of a native cultivar of Campania (cv. Salella) grown in pot during the growing season from May to September 2020. The experimental design included two products: di-1-p-menthene (product V) and kaolin (product K), applied five times at 20 day intervals compared with a control. The following biometric, physiological, and nutraceutical parameters were evaluated: stomatal conductance, chlorophyll a fluorescence, Soil Plant Analysis Development (SPAD) index, relative water content (RWC), shoots growth, total leaf area per plant, trunk cross-sectional area, dry matter partitioning, total polyphenols, and antioxidant activity. The results obtained showed that the application of di-1-p-menthene (V) was able to induce a significant improvement of shoots growth (+37.22%) and trunk cross-sectional area (+46.60%) and a reduction of the stomatal conductance and an increase of leaf RWC values. Application with kaolin had positive effects on the total polyphenol content, with an increase over the control of 240.33% and higher antioxidant activity values. Further studies are necessary to determine the effect of these products on the biometric, physiological and nutraceutical parameters of mature olive trees cultivated in open field conditions.

Deep Convolutional neural network (CNN) in tea leaf chlorophyll estimation: A new direction of modern tea farming in Assam, India

This study presents the uprising of leaf chlorophyll estimation from traditional mechanical method to machine learning-based method. Earlier chlorophyll estimation techniques such as Spectrophotometer and Soil Plant Analysis Development (SPAD) meter demand cost, time, labour, skill, and expertise. A small-scale tea farmer may not afford these devices. The present study reports a low-cost digital method to predict the tea leaf chlorophyll using 1-D Convolutional Neural Network (1-D CNN). After capturing the tea leaf images using a digital camera in a natural light condition, a total of 12 different colour features were extracted from tea leaf images. A SPAD was used to estimate the original chlorophyll value of the tea leaves. The paper shows the correlation of original tea leaf chlorophyll with the extracted colour features of the tea leaf images. Apart from 1-D CNN, the Multiple Linear Regression (MLR) and K-Nearest Neighbor (KNN) were also applied to predict the tea leaf chlorophyll and compared their results with the 1-D CNN. The 1-D CNN model outperformed with an accuracy of 81.1%, Mean Absolute Error (MAE) of 3.01, and Root Mean Square Error (RMSE) of 4.18. The investigation system is very simple and cost-effective. It can be used in tea farming as a digital SPAD for faster and accurate leaf chlorophyll estimation in an easy way.

Association of leaf chlorophyll content with the stay-green trait and grain yield in wheat grown under heat stress conditions

Heat stress is a major production constraint of wheat in South Asia, particularly in the Gangetic plains of India and Bangladesh. The leaf chlorophyll status is a key determinant for a high rate of photosynthesis under stress. The present experiments included 238 genotypes in 2016–2017 and 321 genotypes in 2017–2018 under optimum and under heat stress conditions. Subsequently, a set of 100 genotypes selected on basis of the heat susceptibility index was evaluated in 2018–2019 under heat stress conditions to study the relationship between important physiological traits and yield under stress. A significant correlation of soil plant analysis development (SPAD) value of the two upper leaves with stay-green trait and grain yield indicates the importance of chlorophyll content, both in flag and penultimate leaf, in maintaining leaf areas under greenness (LAUG) and grain yield under heat stress. The SPAD in the flag and penultimate leaf was responsible for 8.8% and 10.9%, respectively, of the variation in grain yield. For the stay-green trait, 8.4% and 7.2 % of the variation was governed by the SPAD value in the flag and penultimate leaf, respectively. These results suggest that, in addition to the flag leaf, the chlorophyll status of the penultimate leaf can be an important criterion for the selection of superior wheat genotypes under heat stress. The genotypes SW-139; SW 108; DWR-F8-35-9-1; NHP-F8-130; DWR-F8-3-1 that maintained a high chlorophyll content in the flag and penultimate leaf can be used further in breeding programmes addressing heat resistance in wheat.

High-throughput phenotyping to detect anthocyanins, chlorophylls, and carotenoids in red lettuce germplasm

Some plant pigments are strong antioxidants and benefit human health. Given their low cost and popularity, biofortified lettuce cultivars can promote consumption of these compounds. In this study, we assessed anthocyanin, chlorophyll, and carotenoid content in 30 red lettuce genotypes, as well as the Soil Plant Analysis Development index (SPAD) and vegetation indices (CIG, CVI, GNDVI, and NDVI), using high-throughput phenotyping. We calculated vegetation indices by using images of the plant canopy obtained from a remotely piloted aircraft (RPA) together with a red, green, and near-infrared band camera. The SPAD index and leaf pigments were measured through traditional laboratory methods, which are costly and time-consuming. Genetic variability among the genotypes for leaf pigments was confirmed by the Scott-Knott test and UPGMA dendrogram. Anthocyanin was the pigment that most contributed to genetic diversity and highly correlated with CIG, CVI, and GNDVI. These indices also moderately correlated with chlorophylls and carotenoids. Genotypes with higher pigment content, especially anthocyanin, had higher indices. Therefore, the image-based plant phenotyping technique correlated with the traditional methodology and can provide an alternative for indirect selection of plants with high leaf pigment content, especially anthocyanin, in red lettuce.

Effect of Vermicompost Enriched with Biofertilizers, Bioagents and Micronutrients on Growth and Yield of Groundnut (Arachis hypogaea L.)

Aims: To study the response of groundnut (Arachis hypogaea L.) to vermicompost enriched with biofertilizers, bioagents and micronutrients.
 Study Design: Field experiment was conducted at Junagadh (Gujarat) with ten treatments comprising of vermicompost enriched with biofertilizers, bioagents and micronutrients viz., Absolute Control (T1), 100% Recommended dose of fertilizers (T2), Vermicompost 2 t/ha (T3), Vermicompost 2 t/ha + Biofertilizers (Rhizobium Bradyrhizobium japonicum + Phosphate Solubilizing Bacteria Bacillus subtilis + Potash Solubilizing Bacteria Frateuria aurantia each at 2 L/ha) (T4), Vermicompost 2 t/ha + Trichoderma harzianum 3 kg/ha + Pseudomonas fluorescens 3 L/ha (T5), Vermicompost 2 t/ha + Beauveria bassiana 3 kg/ha (T6), Vermicompost 2 t/ha + Biofertilizers (Rhizobium + Phosphate Solubilizing Bacteria + Potash Solubilizing Bacteria each 2 L/ha) + Trichoderma harzianum 3 kg/ha + Pseudomonas fluorescens 3 L/ha + Beauveria bassiana 3 kg/ha (T7), Micronutrients (Fe + Zn + Cu + Mn) Grade-V at 40 kg/ha (T8), Vermicompost 2 t/ha + Micronutrients (Fe + Zn + Cu + Mn) Grade-V at 40 kg/ha (T9) and Vermicompost 2 t/ha + Biofertilizers (Rhizobium + Phosphate Solubilizing Bacteria + Potash Solubilizing Bacteria each 2 L/ha) + Trichoderma harzianum 3 kg/ha + Pseudomonas fluorescens 3 L/ha + Beauveria bassiana 3 kg/ha + Micronutrients (Fe + Zn + Cu + Mn) Grade-V at 40 kg/ha (T10) in Randomized Block Design with three replications.
 Place and Duration of the Study: Instructional Farm, Department of Agronomy, College of Agriculture, Junagadh Agricultural University, Junagadh (Gujarat) during kharif seasons of 2019 and 2020.
 Methodology: Five plants were selected randomly from each net experimental plot and tagged. Growth parameters viz., plant height, number of branches, SPAD meter reading and number of root nodules, and yield attributes viz., number of mature pods per plant and pods weight per plant were recorded from that tagged plants and their average was considered for final record. Pod yield and haulm yield were recorded from net plot size of each experiment plot and converted in to hectare base. Shelling percentage was counted on the basis of 150 g pod sample taken randomly from net plot produce.
 Results: The results indicated that the highest plant height (35.64 cm), number of branches per plant (8.11), number of root nodules per plant (154.5) at 45 days after sowing (DAS), dry weight of root nodules per plant at 45 DAS (0.982 g), Soil Plant Analysis Development (SPAD) meter reading at 45 DAS (39.09), number of mature pods per plant (18.40), pod weight per plant (15.37 g), 100-kernel weight (44.08 g) and shelling percentage (73.16%) with the highest pod yield (2.305 t/ha) and haulm yield (3.889 t/ha) were achieved by application of Vermicompost 2 t/ha + Biofertilizers (Rhizobium + Phosphate Solubilizing Bacteria + Potash Solubilizing Bacteria each 2 L/ha) + Trichoderma harzianum 3 kg/ha + Pseudomonas fluorescens 3 L/ha + Beauveria bassiana 3 kg/ha + Micronutrients (Fe + Zn + Cu + Mn) Grade-V at 40 kg/ha, which is considered the more effective application among all treatments improves growth, pod and haulm yield of groundnut under clay soil conditions.

Corn response to row spacing and plant population in the Mid‐South United States

AbstractMid‐South corn (Zea mays L.) producers continuously search for ways to increase grain yield. In this region, growers typically plant on 96‐cm beds to facilitate drainage of excess rainfall and irrigation but are concerned about wide row spacing causing intra‐row stress as plant populations steadily increase. The objective of this research was to determine the effect of row spacing and plant population on morphology and grain yield. The experiment assessed two row spacing (48 and 96 cm) and subplots that contained five plant populations (61,775, 86,485, 111,195, 135,905, and 160,615 plants ha–1). This study took place across six site‐years; in 2017, Starkville and Verona, MS, 2018, two in Starkville, MS, and in 2019, Starkville and Tchula, MS. Pooled over site‐years and plant populations, narrow rows increased grain yield by 5% (p < .01), stalk diameter by 4% (p < .01), and kernels per row by 6% (p < .01), compared to wide rows. Pooled over site‐years and row spacing, plant height, soil plant analysis development (SPAD) value, stalk diameter, kernel rows, kernels per row, and hundred‐kernel weight decreased as plant population increased except for ear height and leaf area index (LAI), which increased. Agronomic optimum plant populations ranged from 104 to 119 thousand ha–1 and were dependent upon site‐year. In conclusion, decreases in inter‐row spacing and increases in intra‐row spacing increased grain yield.

Transcriptome and metabolome analyses revealed the response mechanism of apple to different phosphorus stresses

Phosphorus (P) is an important element in numerous metabolic reactions and signalling pathways, but the molecular details of these pathways remain largely unknown. In this study, physiological, transcriptome and metabolite analyses of apple leaves and roots were compared under different P conditions. The results showed that different P stresses influenced phenotypic characteristics, soil plant analytical development (SPAD) values and the contents of flavonoids and anthocyanins in apple seedlings. The contents of hydrogen peroxide (H2O2) and malondialdehyde (MDA) and the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), acid phosphatase (ACP) and purple acid phosphatase (PAP) were also affected by different P stresses. In addition, RNA sequencing (RNA-seq) was used to characterize the influence of different P stresses on apple seedlings. Compared with control apple plants, there were 1246 and 1183 differentially expressed genes (DEGs) in leaves and roots under the low-P treatment and 60 and 1030 DEGs in leaves and roots under the high-P treatment, respectively. Gene Ontology (GO) analysis indicated that apple trees might change their responses to metabolic processes, cell proliferation, regulation of biological processes, reactive oxygen species metabolic processes and flavonoid metabolic processes under P stress. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis further indicated that DEGs act on the mitogen-activated protein kinase (MAPK) signalling pathway, flavonoid biosynthesis, phenylpropanoid biosynthesis, and ATP-binding cassette (ABC) transporters. The metabolome analysis revealed that the levels of most amino acids and their derivatives, organic acids and flavonoids in roots treated with low-P stress were higher than those in roots of apple seedlings under control growth conditions. Apple seedlings regulate the flavonoid pathway to respond to different phosphorus environments. The results provide a framework for understanding the metabolic processes underlying different P responses and provide a foundation for improving the utilization efficiency of P in apple trees.

Integrative physiological, transcriptome, and metabolome analysis reveals the effects of nitrogen sufficiency and deficiency conditions in apple leaves and roots

Nitrogen (N) is an essential element for plant growth and development. In this study, physiological, transcriptome and metabolite analyses of apple leaves and roots were compared under different N conditions. The results indicated that different N stresses influenced plant growth, the content of soil plant analytical development (SPAD) value and photosynthesis in apple seedlings. The content of hydrogen peroxide (H2O2), and the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS) and glutamine antinotransferase (GOGAT) were also affected by different N stresses. RNA-Seq was used to analysis the influence of different N tolerances in apple seedlings. Gene Ontology (GO) analysis of differentially expressed genes (DEGs) indicated that apple trees might affect the responses to photosynthesis, organic hydroxy compound biosynthetic process, and secondary metabolite biosynthetic process under N stress. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that DEGs focused on photosynthesis and secondary metabolite biosynthetic process. There were 527 differential metabolites in LNL/CKL, 157 in HNL/CKL, 477 in LNR/CKR, and 232 in HNR/CKR. The metabolome analysis indicated that total of 1004 and 389 significant differential metabolites were identified under low N and high N conditions in apple. Apple seedlings regulate the carbon metabolism, nitrogen metabolism and flavonoid pathway to adapt the different nitrogen environments. This research provide understanding for the metabolic processes underlying different N responses and provide a foundation for improving the efficiency of N use in apple trees.

Recommended nitrogen rates and the verification of effects based on leaf SPAD readings of rice.

Modern rice production systems need a reliable, easy-to-use, efficient, and environmentally-friendly method to determine plant nitrogen (N) status , predict grain yield, and optimize N management. We conducted field experiments to determine the influence of different N rates on Soil Plant Analysis Development (SPAD) readings of rice leaves. We also performed field validations to evaluate the grain yield and N use efficiency under recommended N rates. Our results showed that leaf SPAD readings increased as N rates increased. We applied the recommended N based on the relationships between the N rates and leaf SPAD readings at the tillering and booting stages. The recommended N decreased N rates and improved N use efficiency without sacrificing grain yield. When compared to farmer practices (FP), the recommended N rates of optimization (OPT) decreased by 5.8% and 10.0%, respectively. In comparison with FP, the N agronomic efficiency of OPT increased by 5.8 and 10.0% while the partial factor productivity of N increased by 6.0 and 14.2%, respectively. The SPAD meter may be a reliable tool to analyze the N in rice, estimate real-time N fertilization, and improve N use efficiency.