Plant Vigor Research Articles

Indole Acetic Acid (IAA) Mediated Plant Growth Promotion Activity of Fluorescent Pseudomonads and Bacillus spp.

This investigation was made to study the involvement of IAA in plant growth promotion and vigor of wheat plants induced with plant growth promoting rhizobacteria. Nineteen isolates of fluorescent pseudomonads and 11 isolates of Bacillus spp. were subjected to germination percentage and seedling vigor index test. These parameters were determined according to recommended methods by ISTA (1985). The IAA production from selected bacterial isolates, which were showing the potential function of plant growth promotion were further subjected to quantitative analysis using Salkowski’s reagent (2% of 0.5 M FeCl3 in 34% HClO4) for Colorimetric detection. The vigor index and plant growth were significantly increased in Pfa-65 (43.36%) followed by B-18 (42.58%), Pfa-77 (40.83%), B-24 (40.68), Pfa-37(38.82%) and B-38 (38.52). The maximum concentration of IAA was detected in the isolate B-24(36.66 µg/ml) followed by Pfa-65(36.16 µg/ml), B-18(35.98 µg/ml) and Pfa-77(35.72 µg/ml). A positive correlation was observed between concentration of IAA produced and germination percentage with PGPR treatments (correlation coefficient was 0.94). The correlation coefficient was 0.96 between IAA produced and percent increase in vigor index with the treatments. Our data suggests that IAA, a growth promoting hormone, might be the key factor to promote the plant growth directed by the rhizobacteria

Reduced Root Volume at Establishment, Canopy Growth and Fruit Production in ‘Lapins’/‘Colt’ and ‘Regina’/‘Gisela 12’ Sweet Cherry Trees

The success of establishing fruit orchards has traditionally been attributed to the vigor of the nursery plant used. This study aimed to evaluate the post-transplant survival, canopy growth and fruit productivity of two sweet cherry (Prunus avium L.) cultivars (‘Lapins’/‘Colt’ and ‘Regina’/‘Gisela 12’) with different radicular basal volumes of 100%, 50% and 25% and nursery plant types: (i) bare root (BR) or (ii) bagged (B). The initial stem diameter of the plants ranged from 12 to 19 mm, and their height ranged from 1.4 to 1.8 m. Plants grafted onto ‘Colt’ rootstock exhibited twice the initial root volume compared to those grafted onto ‘Gisela 12’. Evaluations were carried out in three commercial orchards during three seasons in the Central Valley of Chile. The results indicated that root volume and nursery type did not affect plant survival and productivity. For ‘Regina’/‘Gisela 12’, only the bag treatment resulted in less trunk cross-sectional area (TCSA) and shoot length, and for ‘Lapins’/‘Colt’, the BR25 treatment showed a lower initial TCSA than other treatments, although without a negative effect on yield. Hence, the presumption about the influence of root volume and plant type on the successful establishment of a sweet cherry on ‘Colt’ and ‘Gisela 12’ rootstock can be discarded. The survival, growth and precocity of the orchard depend more on post-planting conditions and water management than on the number or type of nursery plant roots. It is important to prioritize proper post-planting care and water management for optimal orchard health.

Growth and yield of Brazilian potato cultivars

The analysis of plant growth of cultivars is useful for understanding the dynamics of accumulation and partition of photoassimilates during the crop cycle, and this information is important for the crop management of each cultivar. The objective of this study was to evaluate potato cultivars BRS Ana, BRSIPR Bel, BRS Clara, BRS F63 (Camila) and Macaca for growth and yield, under subtropical climatic conditions of Southern Brazil. Plant samples were collected every 20 days, beginning 40 days after planting (DAP), totaling five collections, and physiological growth indexes and the dry mass partitioning to plant organs were estimated. ‘BRSIPR Bel’ showed the fastest development of assimilatory system. ‘BRS Ana’ had the most vigorous plants and the largest leaf area, reaching the leaf area index 4.0 at 70 DAP. ‘BRSIPR Bel’ e ‘BRS Ana’ had the highest dry mass yield, 214 g and 206 g of dry mass plant-1, respectively. ‘BRS F63’ (Camila) and ‘BRSIPR Bel’ presented earlier tuberization and were the most efficient cultivars in the partitioning of dry mass to tubers, with the highest coefficient of dry mass partitioning to tubers estimated between 40 and 64 DAP. These two cultivars also showed the highest yield of marketable tubers.

Effect of Soil pH Variation on Peanut Plant Growth

This research investigates the qualitative effects of soil pH variation on peanut plant growth, aiming to provide insights into the complex interactions between soil properties and plant responses in agricultural ecosystems. Through semi-structured interviews with ten informants, supplemented by insights synthesized from prior research and theoretical frameworks, the study explores perceived relationships, implications for soil health and nutrient availability, challenges, opportunities, and practical implications for peanut production. Key findings highlight the critical influence of soil pH on peanut growth and productivity, with deviations from optimal pH levels affecting nutrient availability, root health, and overall plant vigor. Participants underscore the importance of targeted soil management practices, including lime application, organic matter incorporation, and crop rotation, in optimizing soil pH and supporting resilient peanut production systems. The study identifies challenges in soil pH management, such as limited accessibility of soil testing services and inadequate farmer knowledge, while also highlighting opportunities for innovation and improvement. The insights gleaned from the study contribute to advancing knowledge in agricultural sciences and inform evidence-based soil management practices for sustainable peanut production.

Phenotypic Diversity of Pomegranate Cultivars: Discriminating Power of Some Morphological and Fruit Chemical Characteristics

In modern agricultural production, where a small number of commercial cultivars dominate, the collection, evaluation, and preservation of germplasm are important tasks to reduce the erosion of genes and preserve biodiversity. The aim of this study is to characterize the morphological and fruit chemical properties of the pomegranate germplasm grown on the East Adriatic coast, including the commercial cultivars ‘Hicaznar’, ‘Granada’, and ‘Wonderful’, and to highlight the characteristics with the greatest discriminating power. The characterization of the tree, leaf, flower, arils, seed, and juice was carried out using the UPOV descriptor. The colors of the peel, arils, and juice were analyzed according to the CIEL*a*b* method, total soluble solids were measured using refractometers, and total acidity was determined by titration with 0.1 M NaOH. The research results showed significant diversity between the cultivars, which were grouped into several clusters using an unsupervised analysis technique. Factors such as plant vigor, plant growth habit, predominant number of leaves per node on young shoots, crown type, fruit shape, fruit shape in cross-section, peel weight, total aril weight, aril weight, number of arils per fruit, seed length and width, seed yield, total acidity, TSS/TA ratio, and color parameters of the peel, arils, and juice showed high variability, indicating their strong discriminating power in determining the phenotypic diversity of pomegranate.

Application of chitosan nanopriming on plant growth and secondary metabolites of Pancratium maritimum L

BackgroundNanotechnology has demonstrated its vital significance in all aspects of daily life. Our research was conducted to estimate the potential of primed seed with chitosan nanoparticles in seed growth and yield by inducing plant secondary metabolism of Pancratium maritimum L. one of the important medicinal plants. Petri dish and pot experiments were carried out. Seeds of Pancratium maritimum L. were soaked in Nano solution (0.1, 0.5, 1 mg/ ml) for 4, 8, 12 h. Germination parameters (germination percentage, germination velocity, speed of germination, germination energy, germination index, mean germination time, seedling shoot and root length, shoot root ratio, seedling vigor index, plant biomass and water content), alkaloids and antioxidant activity of Pancratium maritimum L. were recorded and compared between coated and uncoated seeds.ResultsOur results exhibited that chitosan nanopriming had a positive effect on some growth parameters, while it fluctuated on others. However, the data showed that most germination parameters were significantly affected in coated seeds compared to uncoated seeds. GC-MS analysis of Pancratium maritimum L. with different nanopriming treatments showed that the quantity of alkaloids decreased, but the amount of pancratistatin, lycorine and antioxidant content increased compared with the control.ConclusionsApplying chitosan nanoparticles in priming seeds might be a simple and effective way to improve the quantity of secondary metabolites of Pancratium maritimum L. valuable medicinal plant.

Soil and Mineral Nutrients in Plant Health: A Prospective Study of Iron and Phosphorus in the Growth and Development of Plants.

Plants being sessile are exposed to different environmental challenges and consequent stresses associated with them. With the prerequisite of minerals for growth and development, they coordinate their mobilization from the soil through their roots. Phosphorus (P) and iron (Fe) are macro- and micronutrient; P serves as an important component of biological macromolecules, besides driving major cellular processes, including photosynthesis and respiration, and Fe performs the function as a cofactor for enzymes of vital metabolic pathways. These minerals help in maintaining plant vigor via alterations in the pH, nutrient content, release of exudates at the root surface, changing dynamics of root microbial population, and modulation of the activity of redox enzymes. Despite this, their low solubility and relative immobilization in soil make them inaccessible for utilization by plants. Moreover, plants have evolved distinct mechanisms to cope with these stresses and coregulate the levels of minerals (Fe, P, etc.) toward the maintenance of homeostasis. The present study aims at examining the uptake mechanisms of Fe and P, and their translocation, storage, and role in executing different cellular processes in plants. It also summarizes the toxicological aspects of these minerals in terms of their effects on germination, nutrient uptake, plant-water relationship, and overall yield. Considered as an important and indispensable component of sustainable agriculture, a separate section covers the current knowledge on the cross-talk between Fe and P and integrates complete and balanced information of their effect on plant hormone levels.

Identifying genomic regions associated with key agro‐morphological traits in soft red winter wheat using genome‐wide association study

AbstractAgro‐morphological traits play a significant role in the adaptation of wheat to diverse agroecosystems. Genetic understanding of these traits is crucial to develop cultivars adapted to specific environments and maximize their productivity. This is a comprehensive genome‐wide association study (GWAS) of 230 diverse lines of soft red winter wheat for identifying quantitative trait loci (QTLs) related to eight key agro‐morphological traits. The diversity panel was evaluated in two locations for three consecutive years (2020–2023). A total of 150 significant marker–trait associations were detected, including 65 for three flag leaf traits, 35 for peduncle length, 33 for plant height, 16 for heading date, and one for plant vigor using 27,466 single nucleotide polymorphism (SNP) markers. Eleven high‐confidence major‐effect QTLs explaining greater than 10% phenotypic variance were detected, of which seven were stable, and one showed an association with plant height and peduncle length. QTLs possibly allelic for important dwarfing (Rht23) and vernalization (Vrn‐B1) genes were identified. Six QTLs, QFlw.uga‐1A, QPdl.uga‐1A, QFlw.uga‐2B.2, QPdl.uga‐5A, QPdl.uga‐7A, and QPht.uga‐7B, are presumed to be novel, and nearby candidate gene(s) were identified for all except QPdl.uga‐1A. The pyramiding of favorable alleles from major‐effect QTLs was found to have significant improvement in peduncle length (shortened by 5 cm), flag leaf width (increased by 0.18 cm), and plant height (shortened by 11 cm). This study has improved our genetic understanding of important agro‐morphological traits. These results, upon further validation, can be used in breeding for desirable plant architecture to improve wheat yield potential.

Application of Panchagavya, a Cow-based Liquid Formulation, as a Lever for Sustainable and Enhanced Vegetable Crop Production: A Review

Panchagavya, a fermented liquid bio-formulation derived from cow-based products such as dung, urine, milk, curd and ghee, has recently gained importance in agricultural practices due to its reported effectiveness in enhancing vegetable crop production. Its formulation involves a fermentation process that harnesses the diverse microbial communities present in cow-derived substances, resulting in a potent nutrient-rich solution that is believed to possess plant growth-promoting properties. One of the primary mechanisms underlying its efficacy lies in the diverse array of microorganisms present in the formulation. These microorganisms, including beneficial bacteria, fungi and actinomycetes, play crucial roles in nutrient cycling, disease suppression and soil conditioning. Additionally, Panchagavya contains plant growth-promoting substances such as hormones, enzymes, vitamins and amino acids, which contribute to enhanced nutrient uptake, root development and overall plant vigour. Furthermore, application of Panchagavya has been shown to improve soil health by enhancing microbial activity, increasing organic matter content and improving soil properties. These soil improvements not only benefit the current crop but also have long-term positive implications for soil fertility and sustainability. This multifaceted approach to crop management offers a holistic solution to enhance crop productivity while reducing reliance on synthetic inputs. This review aims to comprehensively analyse the literature on the effects of Panchagavya on vegetable crops, highlighting its mechanisms of action and potential benefits for increased vegetable crop production.

Impact of jasmonates, salicylic acid, and fungal elicitor on the health of <i>Hippeastrum hybridum</i> bulbs achieved by <i>in vitro</i> procedure

Production of high-quality vigorous plant materials obtained by micropropagation requires not only a good regeneration procedure but also efficient ways to enhance their post-transplanting ability to cope with external environmental factors. There is increasing interest in <i>Hippeastrum hybridum</i> on the horticultural market. However, the traditional method of cultivation using seeds and bulbs does not meet the growing demand and requirements of available priming procedures, thus leading to a search for more effective methods of reproduction. The aim of the study was to assess the morphogenetic abilities of bulb and flower explants for regeneration and investigate whether the enrichment of the multiplication process by exposure to elicitors will improve the health of the obtained plants through faster synthesis of phytoalexin. The study revealed that high regeneration efficiency can be obtained by using twin-scales, peduncles, and receptacles. Over 76% of explants were capable of bulblet induction and the micropropagation rates were 2.3, 2.7, and 5.0, respectively. At the rooting stage, the use of regulator-free medium was required, yielding a high percentage of rooted shoots of over 90% (shoots obtained on twin-scales and peduncles). The materials obtained <i>in vitro</i> did not differ morphologically from the initial materials. However, it was noted that, after exposure to the <i>Phoma narcissi</i> fungal elicitor or to jasmonic acid (JA) and jasmonic acid methyl ester (MeJA), the <i>in vitro</i>-derived bulbs were able to synthesize phytoalexin with higher efficiency than the untreated ones. Therefore, the described methods can be useful for <i>H. hybridum</i> multiplication. Moreover, the enrichment of the multiplication process with the stage of exposure to elicitors ensures initial immunity of <i>H. hybridum</i> to the pathogen <i>Phoma narcissi</i>, which can be used as a priming procedure.

Assessing the Effectiveness of Pruning in an Olive Orchard Using a Drone and a Multispectral Camera: A Three-Year Study

The uses of precision oliviculture have increased in recent years to improve the quality and quantity of extra virgin olive oil. In traditional and intensive systems, biennial pruning is often applied to balance and maintain plant vigour, aiming at reducing management costs. This study presents the results of a three-year experiment with the objective of quantifying the effects of biennial pruning on the vegetative vigour of olive trees, investigating the geometric and spectral characteristics of each canopy determined with multispectral images acquired by UAV. The experiment was carried out in an olive orchard located in western Sicily (Italy). Multispectral images were acquired using a UAV in automatic flight configuration at an altitude of 70 m a.g.l. The segmentation and classification of the images were performed using Object-Based Image Analysis (OBIA) based on the Digital Elevation Model (DEM) and orthomosaic to extract the canopy area, height, volume and NDVI for each plant. This study showed that the technology and image analysis processing used were able to estimate vigour parameters at different canopy densities, compared to field measurements (R2 = 0.97 and 0.96 for canopy area and volume, respectively). Furthermore, it was possible to determine the amount of removed biomass for each plant and vigour level. Biennial pruning decreased the number of plants initially classified as LV (low-vigour) and maintained a vegetative balance for MV (medium-vigour) and HV (high-vigour) plants, reducing the spatial variability in the field.

Marsh-orchids of Canada: long-standing mysteries partially solved

SummaryBetween 1959 and 1988, three populations of purple-flowered terrestrial orchids attributable to Dactylorhiza subgenus Dactylorhiza were discovered in Canada. The populations at Timmins, Ontario, and St John's, Newfoundland were strongly marked on both flowers and leaves, in contrast with the anthocyanin-deficient population at Tilt Cove, Newfoundland. All three populations have since experienced a wide range of taxonomic assignments; debates are also ongoing regarding their origin and most appropriate conservation status. Here, we address these questions by combining detailed in situ morphometric analyses based on 52 characters with allozyme profiles and data from nrITS, 15 plastid microsatellites and seven nuclear microsatellites. The allozyme data alone are sufficient to both confirm allopolyploidy and categorically refute past assignments of these populations to D. incarnata, D. maculata, D. fuchsii, D. majalis or D. purpurella. Several morphometric characters, nuclear microsatellites and nrITS all reliably distinguish each of the three study populations, whereas the two sampled subpopulations from St John's proved near-identical morphologically. In contrast, morphological variation within each of the three populations is strikingly low, particularly in characters other than those influenced by plant vigour. Similarly, compared with 14 European populations, the three Canadian populations proved genetically impoverished (two were near-invariant) and likely experienced recent, extreme genetic bottlenecks during establishment. The three populations differ substantially, both morphologically and molecularly, therefore probably representing independent immigration events. Although clearly attributable to D. praetermissa, all three populations deviate significantly in morphology and DNA data from comparable populations sampled across Europe, preventing identification of their precise geographic origins. Any attempt to determine their mode or origin — through natural long-distance transport, or accidental or deliberate introduction by humans – is challenged to explain why three lineages of a single European Marsh-orchid species, each in different ways atypical of that species, arrived independently in North America whereas no other European dactylorchid species has become established there.

Assessing the Effectiveness of Neem oil and Microalgae in the Management of Cowpea (Vigna unguiculata L.) Leaf Spot Caused by Alternaria spp.

The current study aimed to assess the effectiveness of neem oil and microalgae in controlling leaf spot caused by Alternaria spp. in cowpea (Vigna unguiculataL.). The research was conducted during the Zaid season of 2022 at the Central Research Field of the Department of Plant Pathology, SHUATS, Prayagraj, Uttar Pradesh, using a Randomized Block Design with three replications and seven treatments. Analysis of variance (ANOVA) was utilized to draw conclusions from the data. Leaf spot disease caused by Alternaria spp poses a significant threat to cowpea crops, resulting in yield losses and decreased plant vigor. An in vivo study was carried out to evaluate the impact of different concentrations of microalgae combined with neem oil at 1% on plant growth parameters and Disease Intensity (%). The application of microalgae @540 grams in various splits and neem oil @1% was done. Among all the treatments, T4 (Microalgae 48gms @5 DAS 96gms@15,45 DAS + Neem oil @1% showed promising results. Notably, the T4 treatment significantly increased plant height (84.63 cm) and the number of branches(10.83) at60DAS. Moreover, an increased numberof nodules per plant (21.44) was observed at 75 DAS, indicating improved root health and nitrogen fixation. Additionally, the treatment led to longer pod length (34.44 cm) in three pickings, suggesting enhanced yield potential. Furthermore, the combined application of microalgae and neem oil resulted in a significant reduction in disease intensity, with a notable decrease of 24.47% compared to untreated plants and those treated with chemicals (Bavistin). This indicates that the use of microalgae and neem oil together effectively suppressed leaf spot disease caused by Alternaria spp. in cowpea, thereby improving plant health and productivity. In conclusion, these findings underscore the potential use of eco-friendly alternatives like microalgae and neem oil for managing leaf spot disease in cowpea cultivation. Further research in this area is recommended for sustainable agricultural practices.

Impact of Mechanized Crop Establishment Techniques on Growth, Yield, and Microbial Dynamics under Rice-Wheat Cropping System: A Review

The rice-wheat cropping system, predominant across the Indo-Gangetic plains, generates a substantial volume of crop residue, with an annual yield of 7-9 tonnes per hectare of rice residue. Effective management of this residue, whether in-situ or ex-situ, has become an urgent necessity. However, the economic feasibility of transporting residue beyond 20 km from the field is limited. Consequently, in-field residue management through the adoption of specialized machinery has emerged as an imperative solution. The narrow window between paddy harvesting and wheat sowing, compounded by labor scarcity during peak periods, underscores the need for mechanized crop establishment techniques. Machines such as happy seeders, super seeders, turbo seeders, spatial drills, and seed-cum-fertilizer drills are crucial tools in this regard. This paper examines the benefits of mechanized crop establishment techniques on wheat growth, productivity, and soil biological health within the rice-wheat cropping system. These techniques have revolutionized agricultural practices by significantly influencing growth dynamics, yield parameters, and microbial ecology. The adoption of precision seed drills and mechanized tillage equipment has transformed traditional farming methods, facilitating efficient seed placement, soil preparation, residue incorporation, and weed management. This has resulted in improved crop growth parameters, enhanced yield dynamics, better root development, increased nutrient uptake, and overall plant vigor. Furthermore, reduced soil disturbance and decreased weed pressure associated with mechanized operations have created a conducive environment for beneficial microbial communities to thrive. The integration of mechanized crop establishment techniques has a positive impact on both crop productivity and sustainability, highlighting their importance in modern agricultural practices within the rice-wheat cropping system of the Indo-Gangetic plains.

Consumer-grade imaging system for NDVI measurement at plant scale by a farmer robot

The Normalized Difference Vegetation Index (NDVI) is a valuable indicator of plant vigor that is frequently used in agronomic practices to make timely and targeted decisions with the aim of increasing the productivity of the system. NDVI measurements of large-scale fields are typically performed using remote sensing from satellite and aerial imaging devices. However, due to their low spatial and temporal resolution, these technologies may have limitations in precision viticulture. This paper investigates the potential of a proximal sensing system to characterize the vine foliage that makes use of data collected by a farmer robot equipped with an Intel RealSense D435 camera. The camera includes two infrared (IR) sensors in stereoscopic configuration and one RGB sensor, which provide, for each observation, both infrared and visible red channel information, thus making possible pixel-per-pixel NDVI calculation. Solutions to IR filtering and radiometric calibration issues are proposed that significantly improve measurement accuracy and reliability. Since the camera also provides stereo-based 3D scene reconstruction, depth information can be used to separate the plant canopy from the background before NDVI measurement. At the same time, range data can be employed to extract geometric properties of the crop, such as plant height and/or volume. The system is validated in the field in a commercial vineyard at different phenological stages, from the formation of the berries to leaf discoloration and fall. Experimental results show good agreement compared with ground truth provided by a GreenSeeker, with a mean absolute percentage error in the NDVI estimation of 4.6% and a R2 of 0.87 tested over the whole grapevine cycle. Therefore, the proposed sensing system could be a feasible solution to automated NDVI estimation at plant-scale.

Boron Impact on Maize Growth and Yield: A Review

Maize (Zea mays L.) is a vital crop, contributing significantly—at least 30%—to global dietary energy intake and biofuels and ethanol production. This review article delves into the dynamic interplay between boron (B) and maize growth, yield, and agricultural sustainability. Boron, a crucial micronutrient, is pivotal in essential physiological processes such as root development, leaf expansion, and cob formation. These processes are fundamental for ensuring the vigour and productivity of maize crops. Conversely, boron deficiency manifests as thinner leaves with reduced chlorophyll content, compromising plant health, and hindering yield potential. Maintaining adequate boron levels, particularly during reproductive stages, is critical for mitigating the risk of abnormal ears and maximizing the quantity and quality of maize production. Emerging research underscores the significance of foliar boron application at various growth stages of maize, which stimulates growth, facilitates cell wall development, and increases leaf area. This translates to improved light interception and photosynthetic efficiency, ultimately contributing to increased plant vigour and biomass accumulation. Furthermore, exploring innovative approaches for sustainable boron management is crucial. This includes precision fertilization techniques and biofortification strategies to ensure optimal maize production while minimizing environmental impacts. By gaining a deeper understanding of the complex relationship between boron and maize, farmers can develop customized fertilization plans that utilize strategic foliar boron application. This approach unlocks maize's full yield potential and contributes to sustainable agricultural practices, supporting global food security.

Vulnerability of seedlings to herbivore and pathogen attack: the importance of plant vigor and plant nutritional quality in Hymenaea courbaril

Vulnerability of seedlings to herbivore and pathogen attack: the importance of plant vigor and plant nutritional quality in Hymenaea courbaril

The Beneficial Effects of Soluble Silicon Fertilizer in Dendrobium Orchids: Silicon-Augmented Resistance against Damage by Insect Pests and Fungal Pathogens.

The effects of soluble silicon fertilization on monocots and dicots have been widely studied. However, little is known regarding its effects on protecting epiphytes against insect and fungal pests. The efficacy of silicon fertilizer to reduce damage by thrips pest complexes, namely: Thrips palmi Karny, Frankliniella occidentalis Pergande, Chaetanaphothrips orchidii Moulton, and Chaetanaphothrips signipennis Bagnall (Thysanoptera: Thripidae), and the fungal pathogens: Botrytis cinerea Persoon (Helotiales: Sclerotiniaceae) and Fusarium spp. Link (Hypocreales: Nectriaceae) was examined during a nine-month greenhouse trial in Hawaii. The trial assessed yield, quality, and pest damage across three common varieties of dendrobiums. All replicates received additional soluble silicon fertilizer applications alternating weekly between soil drench and foliar (50 mg Si/plant) applications. Yield, quality, and spray length, pest damage, plant vigor, SPAD, and leaf temperature were measured. Data were analyzed using a generalized linear model (glm) with repeated measures followed by post-hoc pair-wise comparisons in R, version 4.3.1. Treatment effects were significant at p < 0.001 for the majority of the explanatory variables including: marketable yield, spray length, thrips damage, and fungal damage. Overall, the lavender variety ('Uniwai Supreme') benefited the most from silicon applications with a 73.0% increase in marketable yield, compared to the white variety ('Uniwai Mist'), which had an increase of 50.6% marketable sprays in contrast to its untreated control. Si benefits conferred to the purple variety ('Uniwai Royale') were intermediate to the lavender and white varieties. Although the magnitude of Si benefits varied among the varieties, all dendrobium varieties significantly benefited from silicon fertilization.

Impact of exogenous melatonin foliar application on physiology and fruit quality of wine grapes (Vitis vinifera) under salt stress.

Soil salinisation is an important abiotic stress faced in grape cultivating, leading to weakened plant vigour and reduced fruit quality. Melatonin as a novel hormone has shown positive exogenous application value. Therefore, this study used wine grape (Vitis vinifera ) 'Pinot Noir' as a test material to investigate the changes of foliar spraying with different concentrations of melatonin on the physiology and fruit quality of wine grapes in a field under simulated salt stress (200mmolL-1 NaCl). The results showed that foliar spraying of melatonin significantly increased the intercellular CO2 concentration, maximum photochemical quantum yield of PSII, relative chlorophyll and ascorbic acid content of the leaves, as well as the single spike weight, 100-grain weight, transverse and longitudinal diameters, malic acid, α-amino nitrogen and ammonia content of fruits, and decreased the initial fluorescence value of leaves, ascorbate peroxidase activity, glutathione content, fruit transverse to longitudinal ratio and tartaric acid content of plants under salt stress. Results of the comprehensive evaluation of the affiliation function indicated that 100μmolL-1 melatonin treatment had the best effect on reducing salt stress in grapes. In summary, melatonin application could enhance the salt tolerance of grapes by improving the photosynthetic capacity of grape plants under salt stress and promoting fruit development and quality formation, and these results provide new insights into the involvement of melatonin in the improvement of salt tolerance in crop, as well as some theoretical basis for the development and industrialisation of stress-resistant cultivation techniques for wine grapes.

Morphological Trait based Genetic Divergence and Correlation in Barley Genotypes for Drought Tolerance

An experiment was conducted to explore the genetic diversity for the selection and utilization of drought-tolerant barley genotypes in future breeding approaches for yield enhancement. The experimental material comprised thirty barley genotypes planted at the Barley Research Area, Department of Genetics and Plant Breeding, CCS Haryana Agricultural University, Hisar, under drought conditions during 2015-16 and 2016-17. All the genotypes were classified into four distinct clusters. Cluster IV occupied the maximum number of genotypes, i.e. 17, followed by cluster I with eight genotypes. Cluster II and III possessed three and two genotypes, respectively. The average inter-cluster distance was found to be highest between clusters II and III (261.7), followed by clusters III and IV (188.1), while the lowest inter-cluster distance was observed between clusters II and IV (73.8). Cluster I, comprised of eight genotypes, exhibited maximum germination per cent. Cluster II consisted of three genotypes, characterized by high initial vigour, early heading and minimum plant height. Two genotypes from cluster III exhibited minimum internode length, longest spike, and maximum number of tillers per meter and were also found promising for the traits viz., culm thickness, number of grains per spike, 1000-grain weight and grain yield per plot. Cluster IV, being the largest one, had 17 genotypes with the characteristic features of early maturity. Number of effective tillers per meter showed significant positive correlation with grain yield per plot. This trait could be used as a key component in the screening and selection of drought-tolerant genotypes. The improvement in barley could be achieved through the use of genotypes namely JB 481 and Lakhan assigned in clusters III. These genotypes might be considered as potential parents to obtain high heterotic response and accordingly better segregant for grain yield under drought condition.