Pre-flowering Stage Research Articles

Impact of the potato inoculation date on potato virus Y load and viral distribution in daughter tubers at harvest

AbstractAged plants are more difficult to infect than young plantlets. This modification of susceptibility is described as mature plant resistance (MPR). For potato virus Y (PVY), MPR is known to lead to low infection rates of plants inoculated at the postflowering stage and a decrease in the number of infected daughter tubers. However, the impact of inoculation date on the capacity of PVY to accumulate in daughter tubers has not been studied so far. Field and greenhouse experiments were carried out to better understand PVY epidemiology and to help potato growers to evaluate consequences of early/late infections on the quality of their crops. In field trials, potato plants (cv. Bintje) were covered by insectproof nets from planting to harvest except for a 14‐day period to expose plants to natural PVY infections. Under controlled conditions, potato plants were mechanically inoculated with PVY at different dates from preflowering stages (early inoculations) to postflowering stage (late inoculations). At harvest, daughter tubers were individually collected and analysed to define proportions and viral load of infected tubers according to the time between virus inoculation and harvest. Our results showed that although the age of plants at the time of inoculation can modify their susceptibility to PVY infection, in return, early and late PVY inoculations lead to similar rates of infected tubers at the plant scale and equivalent viral accumulation in infected tubers. All together, these data revealed that both early/late infections are high risks for the sanitary quality of potato tubers.

Chemical Composition, Antioxidant and Antimicrobial Potential of the Essential Oils from Aerial Parts of Tagetes patula L. at Different Phenological Stages

The current study aims at determining the variability in composition, antibacterial and antioxidant properties of the essential oils extracted from aerial parts of Tagetes patula at different phenological stages of plant growth i.e., the vegetative, full blooming and seed setting stages. The maximum average yield of hydrodistilled essential oils was obtained as 0.083 ± 0.003% (seed setting), 0.068±0.007% (full flowering) and 0.059±0.005% (pre flowering). (Z)-β-ocimene was found to be most abundant compound of essential oil of T. patula, and α-terpinolene, piperitenone, limonene and propanedinitrile, dicyclohexyl were found as major compounds in oil extracted at different phenological stages of plant. Contribution of (Z)-β-Ocimene was highest in full flowering stage (18.27±3.14%) as compared to other two stages where its amount ranged from 12.03-17.17 %. α-Terpinolene the second major component was found highest in the pre-flowering stage (13.86±1.15%) compared to other stages. Significant variation was observed in the percent content of piperitenone during all three phenological stages The antioxidant (DPPH radical scavenging) assay showed that T. patula oils have maximum activity at the pre-flowering stage. Antibacterial activities of the essential oils were observed at the pre-flowering stage against different bacteria; i.e., Bacillus sp., Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Staphylococcus aureus and exhibited promising values of MIC (0.125 % v/v -0.5 % v/v) and MBC (0.25 v/v to 1% v/v) against bacterial cultures.

DTH8 overexpression induces early flowering, boosts yield, and improves stress recovery in rice cv IR64.

Rice yield and heading date are the two discrete traits controlled by quantitative trait loci (QTLs). Both traits are influenced by the genetic make-up of the plant as well as the environmental factors where it thrives. Drought and salinity adversely affect crop productivity in many parts of the world. Tolerance to these stresses is multigenic and complex in nature. In this study, we have characterized a QTL, DTH8 (days to heading) from Oryza sativa L. cv IR64 that encodes a putative HAP3/NF-YB/CBF subunit of CCAAT-box binding protein (HAP complex). We demonstrate DTH8 to be positively influencing the yield, heading date, and stress tolerance in IR64. DTH8 up-regulates the transcription of RFT1, Hd3a, GHD7, MOC1, and RCN1 in IR64 at the pre-flowering stage and plays a role in early flowering, increased number of tillers, enhanced panicle branching, and improved tolerance towards drought and salinity stress at the reproductive stage. The presence of DTH8 binding elements (CCAAT) in the promoter regions of all of these genes, predicted by in silico analysis of the promoter region, indicates the regulation of their expression by DTH8. In addition, DTH8 overexpressing transgenic lines showed favorable physiological parameters causing less yield penalty under stress than the WT plants. Taken together, DTH8 is a positive regulator of the network of genes related to early flowering/heading, higher yield, as well as salinity and drought stress tolerance, thus, enabling the crops to adapt to a wide range of climatic conditions.

Efficacy of halosulfuron-methyl in the management of Navua sedge (Cyperus aromaticus): differential responses of plants with and without established rhizomes

AbstractNavua sedge is a creeping perennial sedge commonly found in tropical environments and is currently threatening many agroecosystems and ecosystems in Pacific Island countries and northern Queensland, Australia. Pasture and crop productions have been significantly impacted by this weed. The efficacy of halosulfuron-methyl on Navua sedge plants with and without well-established rhizomes was evaluated under glasshouse conditions. Halosulfuron-methyl was applied to plants with established rhizomes at three stages; mowed, pre-flowering, and flowering growth stages, whereas plants without established rhizomes were treated at seedling, pre-flowering and flowering growth stages. At each application time, halosulfuron-methyl was applied at four dose rates of 0, 38, 75, and 150 g ai ha−1. Mortality of 27.5%, 0%, and 5% was recorded in rhizomatous Navua sedge when treated with 75 g ai ha−1 of halosulfuron-methyl at the mowed, pre-flowering stage and flowering stages, respectively. At 10 wk after treatment (WAT), there were no tillers in surviving plants treated at any of the application times. By 16 WAT, the number of tillers increased to 15, 24, and 26 in mowed, pre-flowering, and flowering stages, respectively. Although halosulfuron-methyl is effective in controlling aboveground growth, subsequent emergence of new growth from the rhizome confirms the failure of the herbicide to kill the rhizome. Application of 75 g ai ha−1 of halosulfuron-methyl provided 100% mortality in plants treated at seedling and pre-flowering stages, and 98% mortality when treated at flowering stage in non-rhizomatous plants. A single application of halosulfuron-methyl is highly effective at controlling Navua sedge seedlings but not effective at controlling plants with established rhizomes.

Foliar Spray of Micronutrients Alleviates Heat and Moisture Stress in Lentil (Lens culinaris Medik) Grown Under Rainfed Field Conditions.

The simultaneous occurrence of high temperature and moisture stress during the reproductive stage of lentil (Lens culinaris Medik) constrains yield potential by disrupting the plant defense system. We studied the detrimental outcomes of heat and moisture stress on rainfed lentils under residual moisture in a field experiment conducted on clay loam soil (Aeric Haplaquept) in eastern India from 2018 to 2019 and from 2019 to 2020 in winter seasons. Lentil was sown on two dates (November and December) to expose the later sowing to higher temperatures and moisture stress. Foliar sprays of boron (0.2% B), zinc (0.5% Zn), and iron (0.5% Fe) were applied individually or in combination at the pre-flowering and pod development stages. High temperatures increased malondialdehyde (MDA) content due to membrane degradation and reduced leaf chlorophyll content, net photosynthetic rate, stomatal conductance, water potential, and yield (kg ha–1). The nutrient treatments affected the growth and physiology of stressed lentil plants. The B+Fe treatment outperformed the other nutrient treatments for both sowing dates, increasing peroxidase (POX) and ascorbate peroxidase (APX) activities, chlorophyll content, net photosynthetic rate, stomatal conductance, relative leaf water content (RLWC), seed filling duration, seed growth rate, and yield per hectare. The B+Fe treatment increased seed yield by 35–38% in late-sown lentils (December). In addition, the micronutrient treatments positively impacted physiological responses under heat and moisture stress with B+Fe and B+Fe+Zn alleviating heat and moisture stress-induced perturbations. Moreover, the exogenous nutrients helped in improving physiochemical attributes, such as chlorophyll content, net photosynthetic rate, stomatal conductance, water potential, seed filling duration, and seed growth rate.

Combined foliar application of calcium, zinc, boron and time influence leaf nutrient status, vegetative growth, fruit yield, fruit biochemical and anti-oxidative attributes of “Chandler” strawberry

The aim of this research was to evaluate the effect of foliar application of calcium (Ca), Boron (B) and Zinc (Zn) alone and in combination along with different times of application (pre-flowering stage, post fruit development and combined application at both stages) on the plant growth, yield and quality of strawberry fruit. Foliar application of Ca alone and combined with Zn and B were applied. The experiment was arranged under randomized complete block design in split plot arrangement. Irrespective to application time, strawberry plant sprayed with combined application of Ca, Zn and B exhibited significantly increased leaf macro-nutrients (N, P, K, Ca), micro-nutrients (Zn, B, Fe), average fruit weight, yield, fruit size, fruit firmness, significantly higher TSS:TA ratio, ascorbic acid contents, anthocyanin and also antioxidative enzymes activity viz. catalase (CAT), superoxide dismutase (SOD) and peroxidase (POD)] than untreated plants. Similarly, spraying at both stages (pre-flowering and post-fruit development) significantly increased number of leaves, fruits, yield and average fruit weight, significantly higher fruit TSS:TA ratio, vitamin C, anthocyanin and also anti-oxidative enzymes viz. CAT, SOD and POD of strawberry fruit. In conclusion combined foliar application of Zn, B and Ca applied at pre-flowering stage and post fruit development significantly improved the vegetative growth, fruit yield, fruit bio-chemical attributes and antioxidative enzymes attributes.

Effect of Gypsum & Bio-compost Applications on Relative Water Content in Rice Genotypes under Sodic Soil

Sodic soils have immense productivity potential, if managed through proper technology interventions. Bio-compost is prepared by composting pressmud and gypsum received from waste material of mining can be used to reclaim sodic soils. Field experiments were conducted during the June-November of 2018 and 2019 at the ICAR - Indian Agricultural Research Institute, Sub Regional Station, Pusa (Samastipur), Bihar. Experiment was laid out in split-plot design with four treatments i.e. T1(Control plots), T2 (Gypsum@100% G.R. amended plots), T3(Gypsum @ 50% G.R.+ Bio-compost @ 2.5 tha-1 amended plots), and T4(Biocompost @ 5.0 tha-1 amended plots) in main plots and ten rice genotypes G1(Suwasini), G2(Rajendra Bhagwati), G3(Boro-3), G4(Rajendra Neelam), G5(CSR-30), G6(CSR-36), G7(CR-3884-244-8-5-6-1-1), G8(CR-2851-SB-1-2-B-1), G9(CSR-27), and G10 (Pusa-44) in sub plots and replicated thrice. The promising results reveal that the mean of leaf relative water content at pre-flowering stage in the salt-tolerant genotypes ranged from 69.47 % to 82.20 % during 2018 and 69.52 % to 82.24 % during 2019. The mean of leaf relative water content at grain filling stage in all the genotypes varied between 77.55 % to 85.45 % during 2018 and 75.49 % to 85.16 % during 2019. Soil amendments and genotypes interaction was found significantly in both the years at grain filling stage.

Biostimulatory effect of seaweed extract on the fruiting and runner production of Strawberry

The strawberry plant is an herbaceous perennial and having a shallow root system needs effective nutrient management. The conventional farming system involves the enormous use of chemicals which leads to the degradation of plant and soil health. On the contrary, organic fruit production is more beneficial for plant health and organic fruit production has gained momentum due to increasing the cost of fertilizers and growing ecological concerns. Seaweed extracts are considered an organic farm input as they are environment-friendly and safe for human health. Keeping in view the bio-stimulatory potential of seaweed extracts, a study was conducted to elucidate their effect on the blooming, yield, quality, and runners' production of strawberries under polyhouse conditions during the year 2018-19. The seaweed extract (SWE) was used at variable concentrations viz, 0.75 ml L-1, 1.0 ml L-1, and 1.25 ml L-1 which were applied at the pre-flowering stage (PFS) or Fruit set stages (FSS) or both the stages (PSS and FSS). The study revealed that the foliar spray of seaweed extract at pre-flowering and fruit set enhanced the blooming characteristics and runner production. Furthermore, the plant treated with 1.0-1.25 ml L-1 seaweed extract at the pre-flowering and fruit set stage exhibited the highest cumulative yield and better fruit quality characteristics.

Faba bean (Vicia faba L.) growth and seed yield as influenced by zinc and boron micronutrients

The experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University (BAU), Mymensingh during rabi season, to study the effect of zinc and boron on growth and yield of faba bean (Vicia faba L.). The experiment consisted with three levels of zinc viz. 0, 1.0 and 2.0 kg Zn ha-1 and four levels of boron viz. 0, 1.0 kg B ha-1, 0.5 kg B ha-1 (basal application) + 0.5 kg B ha-1 (foliar application at pre-flowering stage) and 0.5 kg B ha-1 (foliar application at 30 days after sowing) + 0.5 kg B ha-1 (foliar application at pre-flowering stage). The experiment was laid out in randomized complete block design with three replications. In case of zinc, the highest plant height (67.9 cm), pods plant-1 (33.3), seed yield (2.24 t ha-1) and stover yield (2.55 t ha-1) of faba bean was observed when fertilized with 1 kg Zn ha-1whereas corresponding lowest values were recorded from control treatment. In case of boron, the highest number of branches plant-1 (6.51), pods plant-1 (39.1), seed yield (2.14 t ha-1) and stover yield (2.42 t ha-1) were obtained from application of 0.5 kg B ha-1 (basal application) + 0.5 kg B ha-1 (foliar application at pre-flowering stage). In interaction, the highest number of branches plant-1 (7.22), pods plant-1 (41.93), seed yield (2.46 t ha-1) and stover yield (3.05 t ha-1) were recorded from application of 1.0 kg Zn ha-1 with 0.5 kg B ha-1 (basal application) + 0.5 kg B ha-1 (foliar application at pre-flowering stage) whereas the lowest seed and stover yields were recorded from control treatment. Based on the present study it can be concluded that application of 1.0 kg Zn ha-1 coupled with 0.5 kg B ha-1 (basal application) + 0.5 kg B ha-1 (foliar application at pre-flowering stage) appears as the promising combination in respect of seed yield of faba bean.

Effect of relative water content in rice genotypes after gypsum and bio-compost amended sodic soil

Sodic soils have immense productivity potential, if managed through proper technology interventions. Biocompost is prepared by composting pressmud (a sugar industry byproduct) received from cane juice filtration and spent wash received from distilleries through microbial aerobic decomposition and gypsum received from waste material of mining can be used to reclaim sodic soils. Field experiments were conducted during the kharif season of 2018 and 2019 at the ICAR-Indian Agricultural Research Institute, Sub Regional Station, Pusa (Samastipur). The promising results revealed that the mean of leaf relative water content at pre-flowering stage in the salt-tolerant genotypes ranged between 69.47 to 82.20 per cent during 2018 and 69.52 to 82.24 per cent during 2019. The mean of leaf relative water content at grain filling stage in all the genotypes varied between 77.55 to 85.45 per cent during 2018 and 75.49 to 85.16 per cent during 2019. Soil amendments and genotypes interaction were found significant in both the years at grain filling stage.

Evaluation of performance and stability of new sources for tolerance to post-emergence herbicides in lentil (

Context Yield losses in lentil (Lens culinaris ssp. culinaris Medik.) caused by weeds are estimated at 20–80%. In the absence of effective broad-spectrum herbicides, the menace of weed has emerged as a serious yield constraint in lentil. Aims Identification of tolerance to two broad-spectrum post-emergence herbicides, imazethapyr and metribuzin. Methods 221 lentil accessions were screened at the experimental research station of the International Center for Agricultural Research in the Dry Areas, Terbol (Lebanon) over four crop seasons (2014/15–2018/19). During the 2014/15 season, a preliminary screening experiment was conducted with 221 lentil accessions in an alpha lattice design with two replications, where accessions were treated at the pre-flowering stage at 150% of the recommended dose of imazethapyr (112.5 g active ingredient/ha) or metribuzin (315 g active ingredient/ha). Based on the preliminary results, 38 accessions were selected for further evaluation. In subsequent testing, the selected accessions were screened at 100% and 150% of the recommended doses of imazethapyr or metribuzin. Key results Herbicide treatments delayed the flowering time and maturation of tested lentil accessions. The plant height of selected tolerant accessions was reduced by 15% and 8% in the plots treated by imazethapyr and metribuzin, respectively. Reduction index (RIsy) was an effective tool to select for herbicide tolerance. Stability analysis indicated that two accessions (IG4400 and IG5722) performed under high rainfall environments while two other accessions (IG323 and IG4605) were adapted to low rainfall environments. Conclusions Four accessions (IG323, IG5722, IG4400, IG4605) were identified as independently tolerant to metribuzin and imazethapyr. Implications The identified herbicide-tolerant accessions can be used to develop herbicide-tolerant cultivars.

Effect of Zinc and Iron on Growth and Productivity of Relay Grass Pea (Lathyrus sativus L.) in New Alluvial Zone of West Bengal

A field experiment was designed to validate the effect of Zinc and Iron on growth and productivity of relay Grass pea (Lathyrus sativus L.) in New Alluvial Zone of West Bengal. The experiment was carried out in BCKV, Kalyani, West Bengal, India during rabi seasons of 2016-17 and 2017-18, following split-split plot design taking relay sowing of lathyrus in main plots [S1: Satabdi (IET 4786), S2: Swarna (MTU 7029)], three lathyrus varieties in sub plot (V1: Nirmal, V2: Prateek and V3: Ratan) and four foliar sprays at pre-flowering and pod development stages in sub – sub plot (F1: Control, F2: 0.5% FeSO4, F3: 0.5% ZnSO4 and F4: 0.5% FeSO4 + 0.5% ZnSO4) with three replications. First date of sowing (S1) i.e., relay sowing of lathyrus in satabadi (IET 4786) and foliar spray of Fe and Zn, either alone or in combination performed better in terms of plant height, dry matter accumulation, CGR, LAI, LAD, seed yield, stover yield and harvest index of different lathyrus varieties due to higher radiation use efficiency and profile moisture contribution.

Enrichment of Zinc and Iron Micronutrients in Lentil (Lens culinaris Medik.) through Biofortification.

Biofortification of pulse crops with Zn and Fe is a viable approach to combat their widespread deficiencies in humans. Lentil (Lens culinaris Medik.) is a widely consumed edible crop possessing a high level of Zn and Fe micronutrients. Thus, the present study was conducted to examine the influence of foliar application of Zn and Fe on productivity, concentration, uptake and the economics of lentil cultivation (LL 931). For this, different treatment combinations of ZnSO4·7H2O (0.5%) and FeSO4·7H2O (0.5%), along with the recommended dose of fertilizer (RDF), were applied to the lentil. The results of study reported that the combined foliar application of ZnSO4·7H2O (0.5%) + FeSO4·7H2O (0.5%) at pre-flowering (S1) and pod formation (S2) stages was most effective in enhancing grain and straw yield, Zn and Fe concentration, and uptake. However, the outcome of this treatment was statistically on par with the results obtained under the treatment ZnSO4·7H2O (0.5%) + FeSO4·7H2O (0.5%) at S1 stage. A single spray of ZnSO4·7H2O (0.5%) + FeSO4·7H2O (0.5%) at S1 stage enhanced the grain and straw yield up to 39.6% and 51.8%, respectively. Similarly, Zn and Fe concentrations showed enhancement in grain (10.9% and 20.4%, respectively) and straw (27.5% and 27.6% respectively) of the lentil. The increase in Zn and Fe uptake by grain was 54.8% and 68.0%, respectively, whereas uptake by straw was 93.6% and 93.7%, respectively. Also the benefit:cost was the highest (1.96) with application of ZnSO4·7H2O (0.5%) + FeSO4·7H2O (0.5%) at S1 stage. Conclusively, the combined use of ZnSO4·7H2O (0.5%) + FeSO4·7H2O (0.5%) at S1 stage can contribute significantly towards yield, Zn and Fe concentration, as well as uptake and the economic returns of lentil to remediate the Zn and Fe deficiency.

Comparative Efficiency of Mineral, Chelated and Nano Forms of Zinc and Iron for Improvement of Zinc and Iron in Chickpea (Cicer arietinum L.) through Biofortification

Nanoparticles (NPs), due to their tailored properties, serve as potential sources of nutrients for the biofortification of edible grains. Chickpeas are a valued legume crop, widely consumed in developing countries. Thus, to improve the Zn and Fe content in chickpeas, a two-year study was conducted to examine the potential of the foliar application of mineral (0.5% Zn and Fe), chelated (0.3% Zn and Fe) and nanoforms (0.5% ZFN) of fertilizers to enhance Zn and Fe content in chickpea. The foliar application of 0.5% ZnO NPs + 0.5% Fe2O3 NPs (ZFN) at the pre-flowering stage showed the highest potential to increase grain yield, Zn and Fe content and their uptake as a single foliar application of nano-fertilizers showed comparable results to two foliar applications of mineral and chelated forms. The grain and straw yield (14.07 and 33.04 q ha−1, respectively) under ZFN treatment was significantly higher over the control (9.20 and 27.49 q ha−1, respectively). A similar trend was observed for Zn and Fe content in grain (42.29 and 86.51 mg kg−1, respectively). For nutrient uptake, ZFN treatment showed the highest uptake of Zn and Fe in grain (604.49 and 1226.22 g ha−1, respectively) and straw (729.55 and 9184.67 g ha−1, respectively). Thus, nano-fertilizers, due to their altered structural properties, demonstrated higher translocation over the mineral and chelated forms of nutrient fertilizers and thus improved yield and nutrient content to a greater extent. Thus, the foliar application of 0.5% ZnO NPs + 0.5% Fe2O3 NPs may prove to be a feasible option for the enrichment of chickpeas with Zn and Fe to ameliorate malnutrition in burgeoning human populations.

Biochemical Changes and Antioxidant Variations in Date Palm (Phoenix dactylifera L.) Varieties during Flower Induction and Development.

The present investigation was carried out to explore the biochemical changes and antioxidant variations, including non-enzymatic and enzymatic antioxidant variations, in the leaves of different varieties of date palm (Phoenix dactylifera L.) belonging to the early, mid-, and late-flowering categories in the United Arab Emirates. The changes in the protein and phenol concentration; the ascorbic acid, reduced glutathione, and α-tocopherol contents; and the activity of peroxidase and polyphenol oxidase were studied in the leaves during the preflowering, flowering, and postflowering stages of the date palms. Two varieties each from the early (Shaham, Khanezi), mid- (Barhee, Nabthasaif), and late- (Khasab, Fardh) flowering types were used in this study. The protein content in the leaves was higher in the early flowering varieties during the preflowering stage but lower in the other two varieties. The phenol content showed an opposite trend to the protein. There was significant variation in the ascorbic acid content and a reduction in glutathione and α-tocopherol between the leaves of different varieties. Similarly, the activity of the antioxidant enzyme ascorbate peroxidase in the leaves was higher during the preflowering stage in all varieties. The superoxide dismutase (SOD), polyphenol oxidase (PPO), and catalase (CAT) activity was highest in the Bharhee leaves for all the stages. The peroxidase activity (POD) was highest in the Fardh variety of date palm, whereas the Khanezi variety exhibited the lowest activity. This study can be used as a baseline for developing more protocols for understanding the possible roles of biochemicals, antioxidants, antioxidant enzymes, and their interactions in the regulation of flower development in different date palm varieties.

Time-Series Growth Prediction Model Based on U-Net and Machine Learning in Arabidopsis

Yield prediction for crops is essential information for food security. A high-throughput phenotyping platform (HTPP) generates the data of the complete life cycle of a plant. However, the data are rarely used for yield prediction because of the lack of quality image analysis methods, yield data associated with HTPP, and the time-series analysis method for yield prediction. To overcome limitations, this study employed multiple deep learning (DL) networks to extract high-quality HTTP data, establish an association between HTTP data and the yield performance of crops, and select essential time intervals using machine learning (ML). The images of Arabidopsis were taken 12 times under environmentally controlled HTPP over 23 days after sowing (DAS). First, the features from images were extracted using DL network U-Net with SE-ResXt101 encoder and divided into early (15–21 DAS) and late (∼21–23 DAS) pre-flowering developmental stages using the physiological characteristics of the Arabidopsis plant. Second, the late pre-flowering stage at 23 DAS can be predicted using the ML algorithm XGBoost, based only on a portion of the early pre-flowering stage (17–21 DAS). This was confirmed using an additional biological experiment (P < 0.01). Finally, the projected area (PA) was estimated into fresh weight (FW), and the correlation coefficient between FW and predicted FW was calculated as 0.85. This was the first study that analyzed time-series data to predict the FW of related but different developmental stages and predict the PA. The results of this study were informative and enabled the understanding of the FW of Arabidopsis or yield of leafy plants and total biomass consumed in vertical farming. Moreover, this study highlighted the reduction of time-series data for examining interesting traits and future application of time-series analysis in various HTPPs.

Response of Gas Exchange Activity and Relative Water Content of Neem in Relation to Weather

Neem is known for its medicinal values and is a hardy plant that can grow in a wide variety of environmental conditions. However, productivity is impacted by unfavourable weather conditions due to different geographical locations. The present study was conducted to study the influence of prevailing weather conditions on certain physiological parameters deciding the reproductive ability of neem trees. The study was conducted in two different locations at different agro-climatic regions of Tamil Nadu, India. Gas exchange parameters like photosynthetic rate, stomatal conductance, transpiration rate and leaf temperature and relative water content during pre-flowering, flowering and post-flowering stages were measured and correlated with temperature, relative humidity, precipitation and wind speed observed from the corresponding location. In both locations, the neem trees recorded significantly higher values for these physiological parameters during the pre-flowering and fruiting stages compared to the flowering stage. The trees with higher Diameter and breast height (DBH) showed higher values for gas exchange parameters compared to the trees with lower DBH.

Nitrogen availability under conventional and conservation tillage in semiarid Inceptisol

The present experiment was conducted to study the spatio-temporal variation of available nitrogen fraction in cotton (Gossypium hirsutum L.) in conservation agricultural based long term experiment (since 2010) during 2019-20. The treatment comprises two distinct practices, i.e. conventional tillage (CT) and zero tillage (ZT). Under ZT, permanent narrow bed without (PNB) and with residue of previous crops (PNB+R); permanent broad bed without (PBB) and with residues (PBB+R); flat bed (FB) and FB with residues (FB+R). Soil samples were collected (0-15 and 15-30 cm) at pre-flowering, flowering, boll formation and harvest stages. Adoption of CA practices increased the NH4-N, NO3-N and mineral-N fractions of nitrogen at different crop growth stages. Highest NH4-N, NO3-N and mineral-N were recorded at flowering and boll formation stage respectively. The effect of crop residue retention and crop establishment methods on available N fractions was prominent up to 15 cm soil depth. Crop residue retained plots recorded significantly higher N fraction compared to respective without residue and CT plots. Residue retained plots of FB, PBB, PNB recorded 50, 25 and 36% higher NO3-N concentration as compared to respective without residues plots at pre-flowering stage. At flowering stage, maximum NH4-N was recorded in PBB+R (17.9 mg/kg) and FB+R plots (17.5 mg/kg), which was approximately 68 and 16% higher over CT and PNB+R plots. The results revealed that zero tillage together with PBB+R could be a viable option over conventional practice for maintaining nitrogen availability to plants under cotton-wheat (Triticum aestivum L.) cropping system in semiarid climate.

Effects of Cuts and Different Phenological Stages on Antibacterial and Antioxidant Activities and Chemical Attributes of Garden Thyme (Thymus vulgaris L.) Essential Oil

Garden thyme is an aromatic plant with various applications in the pharmaceutical, food, and hygienic-cosmetic industries around the world. In this research, field-cultivated plants were harvested in two cuts and three consecutive stages (pre-flowering, flowering, and post-flowering). The essential oil percentage and compositions were identified in the essential oil samples. The antibacterial activity of the essential oil was measured against Escherichia coli and Staphylococcus aureus. The antioxidant activity, total phenol and flavonoid contents, chain-breaking activity, and IC50 were recorded. The highest essential oil percentage (2.56%) was obtained from the pre-flowering stage. The results of GC/MS revealed that p-cymene, γ-terpinene, thymol, and carvacrol were the most important constituents of the studied essential oil. The lowest antibacterial activity was recorded by the second cut at the pre-flowering stage. The highest antibacterial activity against E. coli and S. aureus were recorded by the second cut during the flowering stage and the first cut during the flowering stage, respectively. The lowest MIC was 15.75 μg mL-1 related to the second cut during the flowering stage. The plants had the highest total phenol (16.64 mg GAE g-1 DM) and total flavonoid contents (2.88 mg QE g-1 DM) at the pre-flowering stage. The highest antioxidant activity (IC50 = 134.05 μg mL-1) was observed at the pre-flowering stage. It can be said that phenological stages and cuts can affect essential oil antibacterial and antioxidant activities, as well as its chemical characteristics.

RESPONSE OF CHINA ASTER (CALLISTEPHUS CHINENSIS L.) GENOTYPES TOWARDS FOLIAR APPLICATION OF GA3

China Aster is one of the most popular flower that are used in ornamental garden. The demand for cut flowers of China aster is increasing day by day, but it has not been possible to supply the adequate amount of flowers especially during the festival season. The area under flower production is increasing year after year but farmers are not getting quality seeds in adequate quantity as very few farmers are taking up seed production because flower seeds loose their viability earlier than crop seeds. So, production of adequate quantity of quality seeds is essential to meet the demand. The present investigation was undertaken in Horticulture Research Station, Mondouri, B.C.K.V., Mohanpur, Nadia, West Bengal during Rabi season of 2018-19 and 2019-20. Over two consecutive years, six genotypes were evaluated the potentiality of for its growth and flowering, as well as to estimate the influence of GA3 through foliar application at pre-flowering stage on its seed production. In field three treatments were considered viz. T1 (control i.e.no application of GA3), T2 (GA3@50ppm), T3 (GA3@100ppm). According to the size of flowers, highest was recorded in Local Mix (G6). So, it could be considered as the best performer genotype considering flower diameter. Seed yield plant-1 was recorded highest in Local White (G5), it could be considered as the best performer genotype considering its higher number of flowers plant-1 and number of seeds flower-1. GA3 (100 ppm) could be utilized in a better way for greater enhancement in all those important parameters as overall influence of GA3 has been found to improve seed yield plant-1 and all the important attributes. Concomitant consideration of seed yield and its important attributes may indicate to recommend foliar application of 100 ppm GA3 for enhancement in seed yield in all the genotypes. Similar to the seed yield and its attributes, plant growth and development have been noticed to be positively influenced by GA3 concentrations with a higher side after 100 ppm, may lead to recommend foliar application of 100 ppm GA3 for commercial cultivation of this crop irrespective of the genotypes.