Seedling Vigor Research Articles

Vermiculite in the initial development of coffee seedlings in different containers

Coffea arabica L. is responsible for 81% of the coffee cultivation area in Brazil and has great economic and social importance in the regions it is cultivated. Producing vigorous seedlings in a short period of time has become an increasing challenge in coffee growing. Thus, the objective of this study was to evaluate the initial development of seedlings produced in bags and polyethylene tubes with different levels of vermiculite. A 2x5 factorial scheme was used; the factors were: two containers: polyethylene bags (containing standard substrate, subsoil and manure (7:3) and tubes (commercial substrate based on pine bark) and addition of vermiculite, at levels 0%, 10%, 20%, 30% and 40%. In each type of substrate, the respective amounts of vermiculite were added. The variables analyzed were shoot height, root length, stem diameter, number of leaf pairs, shoot and root fresh and dry matter. Based on the results obtained, it was observed that the seedlings produced in polyethylene bags showed higher significant averages for all evaluated parameters, showing greater vigor and initial development than seedlings produced in tubes. The seedlings produced in bags responded positively to the increase in vermiculite for all analyzed parameters, whereas those produced in tubes show the opposite behavior.

Pre-harvest host-resistance to Aspergillus infection and aflatoxin B1 contaminations in groundnut (Arachis hypogaea L.) genotypes

Groundnut (Arachis hypogaea L.) is an important oil crop in the tropical and sub-tropical countries. Pod and seed coat crack-inducing factors favour Aspergillus species infections and aflatoxin B1 (AFB1) contamination of groundnut. Aflatoxin B1 (AFB1), a toxic secondary metabolite of Aspergillus species, remains a global concern due to its human and animal health, and economic impacts. Thus, the study was conducted at Babile in 2018 with the objective to identify groundnut genotypes resistant to pre-harvest fungal infections, aflatoxin contaminations and associated effects in crop physiology. Seventeen advanced groundnut breeding lines including one commercial cultivar (Werer-961), were evaluated using randomized complete block design and completely randomized design under field and with four replications for laboratory experiments, respectively. Aflatoxin B1 analysis was carried out using Enzyme-Linked Immunosorbent Assay (ELISA) kits. Appropriate statistical procedures, including regression, were employed for data analyses. Highly significant (p<0.01) variation existed among the genotypes for A. flavus and A. niger infections, and the AFB1 contamination ranged from 13.98 (G14) to 1990.86 ppb (G12). The more A. flavus infection, the more reduction in harvest yield and seedling vigour. Fortunately, 53 % of the test materials were found to be resistant to AFB1 production, and frighteningly, none of the AFB1 contaminated genotypes were within the acceptable limit of the lenient standard (10 ppb). All in all, the groundnut genotype (G4) was identified as a good source of pre-harvest resistance to A. flavus infection, AFB1 contamination and seedling vigour so that its inclusion in breeding programs is worthwhile utmost, specifically, in the test environment as pathogen-crop-environment interaction is natural. Since the experiment was employed at one location and for only one year, it is suggested to repeat the experiment across multiple locations and over seasons for reliable recommendation.

Morpho-physiological changes in oil palm (Elaeis guineensis Jacq.) tenera hybrid seedlings raised under different shade levels

Climatic conditions prevailing in oil palm growing states of India indicate the need for shade during primary stage of oil palm nursery for optimum growth and vigour of seedlings. Experiments were conducted to standardize the shade requirement based on growth/quality of oil palm seedlings in summer, rainy and winter seasons by providing 25%, 50% and 75% ultra violet stabilized high density poly ethylene (HDPE) shade nets. Results were found significant among the treatments for most of the growth parameters studied over the seasons. Highergrowth for key characters like seedling height, leaf area, collar girth and dry matter production were recorded at 75% shade level. Similarly, higher chlorophyll content, photosynthetic rate, transpiration rate, stomatal conductance and inter cellular CO2 concentration were observed at 75% shade. Among the season, seedling growth was vigorous in rainy season followed by summer and winter seasons. Hence, provision of 75% shade found to be ideal for raising seedlings during primary stage of nursery in oil palm.

Divergence Studies for Early Seedling Vigour Related Traits, Yield and Yield Components in Rice (Oryza sativa L.)

The present study was carried out in the Autumn 2020-21 using a Randomized Complete Block Design (RCBD) with three replications. Forty-two different genotypes of rice were evaluated in this investigation. These genotypes were assessed based on 21 quantitative traits, which includes yield and yield related traits and early seedling vigour related traits. The Mahalanobis D2 statistic was used for characterizing the genotypes. Based on the D2 analysis, the 42 rice genotypes were grouped into seven clusters. Among these clusters, cluster I was the largest, consisting of 22 genotypes. Cluster III exhibited the highest intracluster distance (22.04), while the maximum inter-cluster distance was observed between clusters II and III (49.06), followed by clusters III and VII (45.84). These results highlight the significance of the genotypes present in these clusters for harnessing heterosis and exploiting the desirable traits associated with them.

Assembly of Tomato Rhizobacteria from Different Functional Groups Improves Seedling Photosynthesis and Growth

The rhizosphere harbors abundant plant growth-promoting rhizobacteria (PGPR) that are vital for plant health. In this study, we screened growth-promoting bacteria from tomato rhizosphere soil, verified their functions, and constructed the optimal combination of growth-promoting bacteria for promoting tomato growth. Furthermore, the effects of these bacteria on various physiological and biochemical parameters of tomato plants were evaluated. A total of 36 strains of rhizobacteria were isolated from tomato rhizosphere soil and their abilities to produce indole-3-acetic acid (IAA), solubilize phosphate and iron carriers were assessed. The bacterial strains with the highest capacities for IAA production (R62, R317), phosphate solubilization (R41, R219), and siderophore production (R25, R325) were selected to form three bacterial combinations: R62 + R219 + R317 + R325 (T1), R62 + R325 (T5), and R317 + R325 (T8). Fifteen days after inoculation, all three combinations showed a stimulatory effect on seedling growth compared to the un-inoculated control. Inoculation with T1, T5 and T8 increased the seedling vigor index by 173.7%, 204.1%, and 168.7%, respectively. Compared to the un-inoculated control, the T1 combination increased the activities of polyphenol oxidase, peroxidase, and the net photosynthetic rate by 132.7%, 18.7%, 58.5%, and upregulated the relative expression levels of the photosynthetic assimilation-related genes RbcL, RbcS, FBPase and FDA by 22.2-, 6.6-, 1.95-, and 2.0-fold, respectively. Our findings provide a potential for constructing rhizobacterial combinations of different functional groups for improving crop growth.

The influence of priming methods, planting dates, and weed interference levels on the vegetative growth, yield, and yield components of AS71 hybrid corn

By carrying out a laboratory experiment, the influence of priming methods, including ZnSO4, BSN, and hydropriming was evaluated on the seed germination of hybrid AS71 corn. Then, the main and interaction effects of the priming methods, planting dates, and weed interference levels were surveyed on the vegetative growth traits, yield, and yield components of corn in a field experiment. Based on the lab experiment, although the maximum germination percentage (100%) was observed in the treated plots by hydropriming 22 h after treatment (HAT), the greatest seedling vigor index (122.99) was recorded with treated seeds by ZnSO4 (0.03 mg L–1) at 8 HAT. The greatest emergence index was observed in the treated plots by hydropriming on both planting dates of June 1 and 11. The interaction of planting dates and weed interference levels revealed that the highest emergence index (14%–17%) occurred in the weed-free plots on both planting dates. BSN recorded the greatest corn 1000-grain weight that was significantly higher than the control plots by 28%. Furthermore, BSN enhanced the corn grain yield compared with the control plots by 63% and 24.9% on the planting dates of June 1 and 11, respectively. BSN, as a nutri-priming approach, by displaying the highest positive effects in boosting the corn grain yield in both weedy and weed-free plots as well as both planting dates, could be a recommendable option for growers to improve the crop yield production.

Determination of the Efficiency of Moringa Leaf Extract Treatments on Seedling Vigor in Marigold

The effect of different planting depths on emergence characteristics was investigated in this study carried out using seeds of Marigold (Tagetes patula) collected from nature. In addition, the most effective dose that can be used in priming treatments was tried to be determined by examining the effects of moringa leaf extract treatments applied at different doses in terms of emergence rate, emergence time, survival seedling rate, true leaf emergence time, emergence speed index, coefficient of velocity of emergence and vigor index values. After the T test, it was determined that different planting depth treatments created statistically significant differences especially in the survival seedling rate. It has been observed that the fact that the planting is exposed causes an increase in the survival seedlings rate. In addition, following hydropriming and moringa treatments, the highest seedling emergence rate at both planting depths was achieved with hydropriming and moringa leaf extract (4 g L-1) treatment. Moreover, moringa leaf extract (8 g L-1) treatments exhibited the earliest emergence compared to other treatments. All treatment groups were statistically different compared to the control group in terms of emergence speed index, coefficient of velocity of emergence and vigor index values in both planting depths, and HP and M3 treatments were the treatment groups that gave the best results. As a result of the study, it has been determined that surface sowing can be recommended in marigold cultivation and moringa treatments improve the emergence characteristics.

Efficacy of different multi-layer hermetic bags on the seed quality of the faba bean (Vicia faba L.) in outdoor storage condition

Faba bean seeds' sustainability correlates with the initial quality of cultivated seeds. The duration of storage is a significant factor that can affect the quality retention of any crop seed. Additionally, the hermetic bags effectively influence the quality of crop seeds during the storage process. This study evaluated two faba bean cultivars, Nubaria 1 and Giza 716, after various storage periods of 6, 12, 18, and 24 months. Seeds stored in 3 and 7-layer hermetic bags have shown significantly improved bulk temperature after 12, 18, and 24 months (neither more than ≈ 30 °C nor less than ≈ 15 °C). However, the relative humidity (RH%) increased significantly in both bags and cultivars throughout the storage periods, reaching 61, 59.77% and 59.53, 57.53% at the end of the storage period for Nubaria 1 and Giza 716 inside the 3 and 7-layer bags, respectively. The seeds' germination % decreased significantly (20%) after 24 months at the 3-layers compared with 13.12% at the 7-layer bags for Nubaria 1 with superior germination% of Giza 716 under the same conditions where the decrease in the percentage of germination reached 15.56% and 8.86% reduction for both 3 and 7 layers, respectively. The seedling vigor index exhibited the same trend of germination % with better results of the 7-layer bags for both cultivars. The moisture content (MC%) was substantially elevated by 1% at the end of the storage for both cultivars and bags. After 12 months, beans considerably increased color deterioration, with a loss of 43.16 and 53.60% for Giza 716 and Nubaria 1 stored in 3-layer bags, respectively; however, 7-layer bags were always better than 3-layer bags (with a loss of 32.56 and 45.56%). Furthermore, storage in 7-layer hermetic bags triggered a significant decrease (14.94%) in the total phenolic (TPC) after 24 months for Giza 716 without a substantial difference with Nubaria 1. Additionally, the simulation showed that after 18 months and 24 months of storage, the Nubaria 1 seeds packed in the 7-layer hermetic bags produced total tannins (TTC) 39.1% and 42.5%, respectively, more than those packed in the 3-layer hermetic bags. That TTC had a negative correlation with the testa's darkness. Taken together, the faba bean seeds could be stored for a long period in the 7-layer hermetic bags, preserving seed quality and expanding marketing prospects.

Genome-wide association mapping combined with gene-based haplotype analysis identify a novel gene for shoot length in rice (Oryza sativa L.)

Key messageGenome-wide association mapping revealed a novel QTL for shoot length across multiple environments. Its causal gene, LOC_Os01g68500, was identified firstly through gene-based haplotype analysis, gene expression and knockout transgenic verification.Strong seedling vigor is an important breeding target for rice varieties used in direct seeding. Shoot length (SL) is one of the important traits associated with seedling vigor characterized by rapid growth of seedling, which enhance seedling emergence. Therefore, mining genes for SL and conducting molecular breeding help to develop varieties for direct seeding. However, few QTLs for SL have been fine mapped or cloned so far. In this study, a genome-wide association study of SL was performed in a diverse rice collection consisting of 391 accessions in two years, using phenotypes generated by different cultivation methods according to the production practice, and a total of twenty-four QTLs for SL were identified. Among them, the novel QTL qSL-1f on chromosome 1 could be stably detected across all three cultivation methods in the whole population and indica subpopulation. Through gene-based haplotype analysis of the annotated genes within the putative region of qSL-1f, and validated by gene expression and knockout transgenic experiments, LOC_Os01g68500 (i.e., Os01g0913100 in RAP-DB) was identified as the causal gene for SL, which has a single-base variation (C-to-A transversion) in its CDS region, resulting in the significant difference in SL of rice. LOC_Os01g68500 encodes a DUF538 (Domain of unknown function) containing protein, and the function of DUF538 protein gene on rice seedling growth is firstly reported in this study. These results provide a new clue for exploring the molecular mechanism regulating SL, and promising gene source for the molecular breeding in rice.

Effects nursery media on Irvingia gabonensis and Dacryodes edulis seedlings and weed dynamics of the media

A field experiment was conducted to assess the effect of different nursery media on performances of Bush mango (Irvingia gabonensis) and African pear (Dacryodes edulis) seedlings. Five nursery media were formulated from topsoil, poultry manure and river sand in the following ratios; 0:3:3, 1:2:3, 1:3:2, 2:3:1 and 3:2:1. The media formulated were analyzed for the physico-chemical properties and seeds of the test crops were sown in each filled polythene bags with the formulated media. The experiment was arranged in a completely randomized design (CRD). The results obtained show significant (P≤0.05) media effects on days to first and 50% seedling emergence and percentage total emergence in Bush mango but non-significant in African pear. Number of days to last seedling emergence was significantly (P≤0.05) influenced by media in African pear leaf number and plant height for 10 weeks were responsive to differences in media in both crops. Media influenced total dry weight only in Bush mango while dry matter distribution pattern varied significantly in African pear. In both crops, percentage total seedling emergence and seedling vigour were better in medium 1:2:3. Therefore, from the results, the differential influence of media on seedling growth as evidence in the study suggested the need for broader evaluation of media for different tropical tree species to identify the most appropriate medium for each species that will ensure better vigorous seedling production for plantation and/or orchard establishment. Also, the results showed significant variation in weed flora composition, comprised of 35 species made up of 14 families. The families of Asteraceae, Gramineae, Amaranthaceae and Acanthaceae were predominant. Annual weed species and broadleaf were predominant.

Germination of bean seeds (Vigna unguiculata L. Walp.) in strong electric fields

This paper presents a tutorial for the germination of bean seeds (Vigna unguiculata L. Walp.) in strong electrostatic fields up to 1240 V/cm. The seeds were allowed to germinate under different electric field strengths for 48 h. Although most of such germination experiments did not show any visible effect, the field strength of 945 V/cm strongly increased the seedling's vigor during the early growth stage. In the end, 30 % more yield was obtained from stimulated seeds when compared to the control group. This article postulates for the first time a hypothesis of the mechanism of action of the electric field during germination. In biological cells of any species, water confined between narrow surfaces can undergo a phase transition that shifts its melting point to higher temperatures when an external electric field is applied. This effect has already been known as electrofreezing, and has been confirmed by several experimental and molecular modeling studies. As a consequence, the transport kinetics of molecules across cell organelle membranes might be altered, which in turn leads to different plant properties.With emphasis on the presented method, this work reports:•An inexpensive electric circuit for the generation of strong electric fields•Instructions regarding the setup and operation of an adequate germination chamber

Germination responses with different treatments, seed vigour and seedling growth of Pterolobium stellatum (Forssk.) provenances stored from 19 to 30 years

Knowledge of the genetic variability of different species for conservation purposes and quality seedling production after longer storage time is important. The aim of the research paper was to examine the effect of longer seed storage periods (19–30 year) on seed viability, seed vigour and initial growth of seedlings from five provenances of Pterolobium stellatum (Forssk). Seeds collected from Dabena, Gambo, Agaro, Bishofitu, and Merti localities and stored for 19, 19, 21, 25, and 30 years, respectively used for the study. Different seed dormancy-breaking treatments such as; soaking in cold water for 48 h (CW-48); soaking in hot water for 10 min (HW-10); 20 min (HW-20) and mechanical scarification; i.e., nicking (NK) used for the germination of the seeds. A randomized complete block design was used for the experiment and the study undertaken in a greenhouse. For each treatment, four replications and for each replication, 50 seeds were used. One-way analysis of variance was used for germination index, early seedling growth and seed vigour index data. The results showed that for all the provenance seeds stored for different periods, NK treatment resulted relatively in a higher mean germination percentage and germination indices as compared to the other pre-treatments. The seed vigour index result showed significant differences among the different provenances (P < 0.001). Similarly, there were significant differences among the early growth of seedlings germinated from different provenance seeds (P < 0.001). The seeds collected from Merti provenance and stored for 30 years and Dabena provenance, stored for 19 years, have relatively resulted in higher mean germination index, seed vigour and seedling growth relative to the other studied provenance seeds. We observed that provenance had a more significant influence on germination, seed vigour and seedling growth than the seed storage period for the P. stellatum. Finally it is recommended that despite there is inter population variation, the seeds of P. stellatum can be stored for a longer time and application of nicking as a dormancy breaking treatment could enhance seed germination of the species.

Seed Priming with Reactive Oxygen Species-Generating Nanoparticles Enhanced Maize Tolerance to Multiple Abiotic Stresses.

Climate change-induced extreme weather events (heat, cold, drought, and flooding) will severely affect crop production. Increasing the resilience of crops to fluctuating environmental conditions is critically important. Here, we report that nanomaterials (NMs) with reactive oxygen species (ROS)-generating properties can be used as seed priming agents to simultaneously enhance the tolerance of maize seeds and seedlings to diverse and even multiple stresses. Maize seeds primed with 40 mg/L silver nanoparticles (AgNPs) exhibited accelerated seed germination and an increased germination rate, greater seedling vigor, and better seedling growth under drought (10% and 20% PEG), saline (50 and 100 mM NaCl), and cold (15 °C) stress conditions, indicating enhanced resilience to diverse stresses. Importantly, maize resistance to simultaneous multiple stresses (drought and cold, drought and salt, and salt and cold) was markedly enhanced. Under drought conditions, seed priming significantly boosted root hair density and length (17.3-82.7%), which enabled greater tolerance to water deficiency. RNA-seq analysis reveals that AgNPs seed priming induced a transcriptomic shift in maize seeds. Plant hormone signal transduction and MAPK signaling pathways were activated upon seed priming. Importantly, low-cost and environmentally friendly ROS-generating Fe-based NMs (Fe2O3 and Fe3O4 NPs) were also demonstrated to enhance the resistance of seeds and seedlings to drought, salt, and cold stresses. These findings demonstrate that a simple seed priming strategy can be used to significantly enhance the climate resilience of crops through modulated ROS homeostasis and that this approach could be a powerful nanoenabled tool for addressing worsening food insecurity.

SALINITY TOLERANCE OF QUINOA (CHENOPODIUM QUINOA WILLD.) GENOTYPES TO ELEVATED NACL CONCENTRATIONS AT GERMINATION AND SEEDLING STAGES

Evaluating quinoa genotypes for salinity tolerance at germination and seedling stages is a prerequisite for plant breeders. Thus, the scrutiny of 19 quinoa genotypes at different salinity levels under controlled laboratory and greenhouse conditions occurred at the germination and seedling stages. This study aimed to identify the most tolerant genotypes to elevated salinity levels at germination and seedling stages and to determine the traits of a robust association with salinity tolerance using a factorial experiment based on a randomized complete block design in three replications. The four salinity solutions used were zero (control), 3000, 6000, and 9000 ppm NaCl. Increasing concentrations of NaCl caused a gradual and significant decrease for all studied traits except mean germination time, which significantly increased. At all salinity-stress levels (3000, 6000, and 9000 ppm NaCl), the studied 19 genotypes underwent classification based on their salinity tolerance index (STI) into three categories, i.e., tolerant, moderately tolerant, and sensitive. The four most salinitytolerant quinoa genotypes under all studied salinity-stress conditions were Rainbow-2, Ql3, RH, and KvlSRA2. The strongest correlations were between STI and each of seedling length, root length, seedling fresh weight, seedling vigor index I, and seedling vigor index II under 3000 ppm; germination percentage, speed germination index, seedling extent, root length, seedling fresh weight, and seedling vigor index II under 6000 ppm; and shoot length and seedling vigor index I under 9000 ppm salinity concentration level. Traits showing sturdy correlations with STI, high heritability estimates, high expected genetic advance, and wide phenotypic and genotypic variability were seedling dry weight, seedling fresh weight, seedling vigor index II, and speed germination index at all salinity stress concentrations; they are recommendable as selection criteria for salinity tolerance in quinoa at germination and seedling stages.

Optimisation of Seed Priming Techniques in Paddy

Aim: To determine the ideal concentration of each priming agent among several selected concentrations which could produce robust paddy seedlings under laboratory conditions.&#x0D; Place of Study: The present investigation was carried out at College farm, Agricultural College, Bapatla.&#x0D; Methodology: Certain seedling vigour traits such as germination percentage, shoot length, root length, seedling length, seedling dry weight, seedling vigour index-I &amp; II were recorded and analysed using crompletely randomized block design (CRD). Best concentration is the one with higher vigour indices.&#x0D; Result: The results revealed that, 1% Nacl, 40 ppm ascorbic acid, 150 ppm gibberellic acid, 2 % neem leaf extracts, 0.5 &amp; 0.1 % P &amp; Zn were optimum concentrations under each priming technique. When compared among all the techniques, priming with gibberellic acid @ 150 ppm performed better in terms of all the vigour traits.

Development and Evaluation of Zinc and Iron Nanoparticles Functionalized with Plant Growth-Promoting Rhizobacteria (PGPR) and Microalgae for Their Application as Bio-Nanofertilizers.

Micronutrient deficiencies are widespread and growing global concerns. Nanoscale nutrients present higher absorption rates and improved nutrient availability and nutrient use efficiency. Co-application of nanofertilizers (NFs) with biological agents or organic compounds increases NF biocompatibility, stability, and efficacy. This study aimed to develop and evaluate zinc and iron bio-nanofertilizers formulated with plant growth-promoting rhizobacteria (PGPR) and microalgae. Nanoparticles (NPs) were synthesized with the co-precipitation method and functionalized with Pseudomonas species and Spirulina platensis preparation. NPs were characterized and evaluated on seed germination, soil microbial growth, and early plant response under seedbed conditions. NPs corresponded to zinc oxide (ZnO; 77 nm) and maghemite (γ-Fe2O3; 68 nm). Functionalized nanoparticles showed larger sizes, around 145-233 nm. The seedling vigor index of tomato and maize was significantly increased (32.9-46.1%) by bacteria-functionalized ZnO- and γ-Fe2O3-NPs at 75 ppm. NFs at 250 and 75 ppm significantly increased bacterial growth. NFs also improved early plant growth by increasing plant height (14-44%), leaf diameter (22-47%), and fresh weight (46-119%) in broccoli and radish, which were mainly influenced by bacteria capped ZnO- and γ-Fe2O3-NPs at 250 ppm. Beneficial effects on plant growth can be attributed to the synergistic interaction of the biological components and the zinc and iron NPs in the bio-nanofertilizers.

Integrating Association Mapping, Linkage Mapping, Fine Mapping with RNA Seq Conferring Seedling Vigor Improvement for Successful Crop Establishment in Deep Sown Direct-Seeded Rice

BackgroundOngoing large-scale shift towards direct seeded rice (DSR) necessitates a convergence of breeding and genetic approaches for its sustenance and harnessing natural resources and environmental benefits. Improving seedling vigour remains key objective for breeders working with DSR. The present study aims to understand the genetic control of seedling vigour in deep sown DSR. Combined genome-wide association mapping, linkage mapping, fine mapping, RNA-sequencing to identify candidate genes and validation of putative candidate genes were performed in the present study.ResultsSignificant phenotypic variations were observed among genotypes in both F3:4:5 and BC2F2:3 populations. The mesocotyl length showed significant positive correlation with %germination, root and shoot length. The 881 kb region on chromosome 7 reported to be associated with mesocotyl elongation. RNA-seq data and RT-PCR results identified and validated seven potential candidate genes. The four promising introgression lines free from linkage drag and with longer mesocotyl length, longer root length, semi-dwarf plant height have been identified.ConclusionThe study will provide rice breeders (1) the pre breeding material in the form of anticipated DSR adapted introgression lines possessing useful traits and alleles improving germination under deep sown DSR field conditions (2) the base for the studies involving functional characterization of candidate genes. The development and utilization of improved introgression lines and molecular markers may play an important role in genomics-assisted breeding (GAB) during the pyramiding of valuable genes providing adaptation to rice under DSR. Our results offer a robust and reliable package that can contribute towards enhancing genetic gains in direct seeded rice breeding programs.

Influence of Seed Priming and Growing Medium on Germination and Seedling Vigour of Tamarind (Tamarindus indica L.)

A field experiment was conducted in 2020–21 at the Fruit Research Station, Imaliya, Department of Horticulture, JNKVV, Jabalpur. The AFRBD (Asymmetrical Factorial Randomized Block Design) was set up with 20 distinct treatment combinations of soil media Soil + Sand, Soil + Vermicompost, Soil + Sand + Vermicompost, Soil +Vermicompost + Biofertisol, Soil + Vermicompost + Azatobactor + PSB + KSB and plant growth regulator i.e. GA3 0 ppm (control), GA3 100 ppm, GA3 200 ppm, GA3 300 ppm. The vigour and germination of seeds were significantly impacted by the type of media used and the usage of plant growth regulators. In regard to the growth parameter, better values for seedling height, number of leaves and stem girth at 30, 60 and 90 days after sowing were found with treatment GA3 200 ppm. Growth metrics, such as root length, fresh shoot weight, dry shoot weight and dry root weight at 120 days, revealed improved results with a higher vigour index when the combination of GA3 200 ppm + growing medium (soil+ vermicompost+ Biofertisol) were applied. The GA3 200 ppm with growing medium (Soil+ Vermicompost+ Biofertisol) were proven to be better in terms of the seed germination parameters. Minimum time was taken for seed germination and increased seed germination percentage had been recorded at 30 days after planting.

Dipping vigorous seedling roots in phosphorus-enriched slurry at transplanting efficiently increases lowland rice yields

P-dipping refers to the placement of phosphorus (P) fertilizer at the root system during transplanting of rice by adhering P-enriched slurry to the seedling roots. This approach is beneficial for smallholder farmers in sub-Saharan Africa who apply small amounts of P to highly P-fixing soils. This study aimed to identify the optimum seedling age for maximizing the impact of P-dipping. Pot experiments revealed that the adhered amounts of slurry to the roots with P-dipping increased in a sigmoidal pattern against seedling age. Correspondingly, the effect of P-dipping on the initial biomass was enlarged with older seedlings in a sigmoidal pattern, increasing slowly during the young seedling age (2.9–4.5 leaves), sharply during the intermediate seedling age (4.5–6.3 leaves), and plateauing during the old seedling age (6.3–7.0 leaves). Combining P-dipping with much older seedlings (> 7.0 leaves) resulted in severe transplanting shock and plant death. On-farm trials on 90 fields in Madagascar demonstrated a significant interaction between seedling age and P treatment on grain yield. The highest yield gains over the control from P-dipping were observed in seedlings with intermediate age (1.0 ​t ​ha−1), followed by old (0.7 ​t ​ha−1) and young (0.6 ​t ​ha−1) seedlings. These results suggested that vigorous and intermediate seedlings with higher slurry adherence than young seedlings and a lower risk of transplanting shock than old seedlings benefited most from P-dipping. This finding provides smallholder farmers with practical knowledge on how to apply the P-dipping more efficiently for achieving improved P management for sustainable rice production.

Variability for seed germination and seedling vigour in aging groundnut (Arachis hypogaea L.) seeds after storage under ambient conditions

Seed germination and seedling vigour in aging seeds of 32 groundnut genotypes was studied under ambient storage conditions to assess the extent of variability for these traits under storage. The association, if any of these traits with seed soil content and seed mass was also examined. Both,seed germination and seedling vigour declined with aging of the groundnut seeds in all test genotypes. However, the rate of decrease varied among the genotypes suggesting significant genotypic difference and possibility of their improvement through breeding. Aging also has strong negative effect on both, root and shoot growth of the seedlings, but profound effect was observed on root growth. Seed germination and seedling vigour are not associated with seed oil content, but seedling vigour is positively correlated with seed mass. The results indicate the possibility of developing new groundnut genotypes that retained good levels of seed germination and seedling vigour even in storage for 12 months under ambientconditions. Further, it is also possible to combine enhanced high seed oil content with high seed germination and seedling vigour. As seed germination and seedling vigour are associated with pod yield, it may be desirable to evaluate the advanced breeding lines for these traits besides other yield and yield parameters.