Seedling Quality Research Articles

Improving the quality of media and Robusta coffee seedlings with mycorrhizal (AMF) and rock phosphate

The quality of the nursery media is very important to producing healthy and good Robusta coffee seeds. This study aims to improve the quality of media and Robusta coffee seedlings by the application of arbuscular mycorrhizal fungi (AMF) and rock-phosphate (RP). The AMF as the first factor consisted of four levels, namely 0, 5, 10, and 15 g/polybag, while the second factor RP consisted of four levels, namely 0, 1.25, 2.50, and 3.75 g/polybag. Each treatment was repeated three times and the whole treatments were arranged according to a completely factorial randomized block design. The seedling in a nursery was planted in the polybag and placed in a screen house with 20% shade. Each polybag is contained 10 kg of Podzolic soil (Ultisols) which was collected in Keumala sub-district, Pidie, Aceh. Before being transferred to polybags, seedlings were planted on Rockwall media. After 90 days after planting (DAP), the soil was dismantled for analysis. Indicators of soil quality from the media nursery analyzed included pH, organic C, available P, and exchangeable K. The parameters of seedling growth measured were plant height, number of leaves, and mycorrhizal colonization percentage at 90 DAP. The results of the experiment showed that there was an interaction effect between mycorrhizae (AMF) and RP application. The application of AMF and RP can improve the quality of Robusta coffee seedling media, indicated by the significant effect on soil pH H2O, available P, and the number of leaves. The best combination application was generally obtained from AMF 15 g/polybag and RP 2.50 g/polybag treatment.

Morfofisiologia e qualidade de mudas de Alibertia edulis cultivadas sob contrastes luminosos e resíduo orgânico

ABSTRACT Organic residue in the substrate and the availability of light influence the production of high-quality seedlings for ex situ cultivation of native forest species. This study aimed to evaluate the effect of doses of chicken manure incorporated in the soil and shading levels on the morphophysiological responses and quality of Alibertia edulis (Rich.) A. Rich seedlings. Five doses of chicken manure (CM) were tested, 0.00, 2.08, 4.16, 6.24, and 8.32 g CM kg-1 soil, under two shade conditions, 0% (full sun) and 50% shading. At 215 days after transplanting, the maximum height obtained for A. edulis was 47.35 cm with 5.64 g CM kg-1 soil under 50% shade. Shaded seedlings had a higher number of leaves. The maximum leaf and root areas were 796.64 and 118.83 cm2 with 5.32 and 4.21 g CM kg-1 soil, respectively, both under 50% shade. Seedlings in 0% shade had lower physiological indices. Shading levels did not affect stomatal limitation, but CM contributed to physiological efficiency. Shoot biomass was higher under 50% shade with higher CM doses. The highest quality indexes occurred with 3.98 and 6.28 g kg-1 CM under 0 and 50% shade, respectively. A. edulis seedlings responded positively to the addition of CM to the soil and presented plasticity under contrasting light conditions. A. edulis seedlings produced under 50% shading with the addition of 6.24 g CM kg-1 soil presented high morphophysiological and seedling quality indicators. The addition of 4.32 g CM kg-1 soil contributed to high seedling quality under full sun conditions.

Produção de mudas de melancia em diferentes substratos sob estresse salino

ABSTRACT Salt stress affects the production of watermelon (Citrullus lanatus) seedlings. However, substrates with alternative materials in their composition can mitigate the harmful effects on the formation of watermelon seedlings. Thus, the objective of the present study was to evaluate the emergence and production of watermelon seedlings grown in different substrates under salt stress. The research was conducted in an agricultural greenhouse belonging to the Universidade da Integração Internacional da Lusofonia Afro-Brasileira, Redenção, Ceará, Brazil. The experimental design used was completely randomized in a split-plot scheme. The plots were five levels of electrical conductivity of irrigation water (ECw: 0.5, 1.5, 2.5, 3.5, and 4.5 dS m-1) and the subplots consisted of two formulations of substrates (SB1: sandy soil + sand + bovine manure; and SB2: sandy soil + sand + biochar; both in a 1:1:1 proportion on volume basis), with five repetitions of 25 seeds. The increase in the electrical conductivity of irrigation water from 1.5 dS m-1 reduces the percentage, speed index, and mean speed of emergence and increases the mean time of emergence of the watermelon crop. Substrate formulated with biochar reduces the time and increases the emergence indexes, besides enabling higher growth and biomass accumulation of watermelon seedlings. Salt stress reduces the growth, biomass, and quality of watermelon seedlings, but with less intensity with the addition of biochar.

Early-stage detection of root freezing injuries of Scots pine (Pinus sylvestris L.) seedlings by impedance loss factor and hydraulic conductance.

The condition of the root system affects the quality of seedlings in forestry and horticulture. Previously, the electrical impedance loss factor (δ) and the reverse-flow hydraulic conductance (Kr ) of the roots of Scots pine seedlings were found to increase when assessed a few days after frost damage. How these variables change with time after the root damage is unknown. We arranged an experiment with 1.5-year-old Scots pine seedlings exposed to -5°C or -30°C, with the control seedlings kept at 3°C. Then δ and Kr of roots were monitored for five weeks in favourable growing conditions. The properties of the roots were observed to be in a dynamic state after the damage. A significant difference in δ was found between the test temperatures -30°C vs -5°C and 3°C (P=0.004 and P<0.001, respectively). The clearest effect of freezing injuries on δ of roots was observed in the first measurement one week after the freezing test. The temperature significantly affected Kr, too, with a significant difference between the low-temperature treated plants -30°C vs -5°C and control (P<0.001 respectively). The difference in Kr between -30 °C and the other two temperatures increased with time and was the largest in the last samples, taken after five weeks. We conclude that the impedance loss factor may detect root damage if the measurements occur early enough after the damage, but a longer time difference (3-5 weeks) is needed according to the reverse-flow hydraulic conductance. This article is protected by copyright. All rights reserved.

Review on Factors Affecting Early Survival of Tree /Shrub Seedlings and it’s Remedy in Restoration Sites of Ethiopia

Abstract Restoration activities in degraded and/or deforested forest landscapes are common and old occurrences around the world. Tree planting is common in most forest landscape restoration initiatives. In Ethiopia, eight seedling-based landscape restoration options are identified to alleviate land degradation and its consequences. The primary purpose of this work was to review factors affecting the early survival of tree and shrub seedlings and their remedies in the restoration sites of Ethiopia. Drought and moisture stress, low soil fertility, poor seedling quality, weak species site matching, termites, livestock grazing, and seasonal frost are the basic factors that hinder the survival and growth of seedlings in the field. In situ rainwater harvesting structures, fertilizer application, the use of quality seedlings, the right species site matching, and the exclusion of livestock and grazing animals from planted seedlings are the remedies that must be employed to increase the success of tree-based restoration practices. Thus, further investigation of the factors affecting the survival of seedlings in the out-planting sites and remediation accordingly is necessary to ensure the productivity and sustainability of restoration practices in Ethiopia.

Response of Cocoa (Theobroma cacao L.) Seedling Growth on Various Growing Media and Organic Plant Supplements

Cocoa (Theobroma Cacao L.) as a plantation crop which success is determined by healthy and quality seedlings. The use of planting media with a mixture of manure and plant organic supplements may result in healthy soil because it contains soil microorganisms that are beneficial and may support the growth of cocoa seedlings. Purpose of this study was to determine the initial growth response of cocoa seedlings on various growing media and dosages of an organic plant supplement as liquid organic fertilizer. The research was conducted in February–September 2022 in a nursery located in Kradenan, Purwoharjo, Banyuwangi Regency and in Agricultural Laboratory of University of Jember, Bondowoso Campus, Bondowoso Regency. Study was carried out in a 4 x 4 factorial using a randomized block design with three replications. The first factor was planting media which consisted of four levels of treatment, namely soil + chicken manure, soil + goat manure, soil + cow manure, and soil + rabbit manure. The second factor was dose of organic plant supplement which consisted of 4 levels, namely the control treatment of 0, 50, 100, and 150 mL polybag-1. Data were analyzed using analysis of variance and follow-up tests using Duncan’s multiple range test at 5% level. Variables observed included seedling height, number of leaves, stem diameter, leaf length, leaf width, number of roots, root length, fresh weight, and dry weight of seedlings. The results showed that there was an interaction effect on all parameters except seedling height, number of leaves, and number of roots. The conclusion of the study showed that there was an effect of interaction treatment with the best treatment combination planting media using cow manure and organic plant supplement dose of 50 mL polybag-1.

EFFECT OF SEED SOURCE AND SEED SIZE ON THE EARLY GROWTH OF ANACARDIUM OCCIDENTALE SEEDLINGS

Seed size and seed origin forms a very important element in the quality of seedlings produced in the nursery. This study investigated the effects of seed size and seed source on early growth of Anacardium occidentale seedlings. Seeds collected from mother tree at three sources (Somorin, Funaab and Camp locations) were sorted into Large, Medium and Small sizes. Collected and sorted seeds, raised in 54 poly pots was laid out in 3 x 3 factorial in Completely Randomized Design (CRD). Data was collected fortnightly for 12 weeks and it was subjected to Analysis of Variance (ANOVA) in SAS. Large sized seed had significantly (p&lt;0.05) produced higher seedling height (26.39cm), number of leaves (10.82), leaf area (82.27cm2), collar diameter (5.20mm), total fresh weight (22.72g), total dry weight (6.26g), fresh shoot weight (18.22g) and dry shoot weight (5.09g). Seeds sourced from Funaab had significantly (p&lt;0.05) higher effect on seedling height (26.87cm) and fresh root weight (4.87g). There was no significant difference (p&gt;0.05) in the effect of source on some morphological parameters, Camp location had the highest effect on leaf area (77.39cm2) and collar diameter (5.19mm). Seeds sourced from Camp significantly (p&lt;0.05) enhanced total dry weight (5.95g), dry shoot weight (4.81g) and absolute growth rate (0.60g/week). There was no significant difference (p&gt;0.05) in the combined effect of seed source and seed size on A. occidentale seedling growth. To produce quality seedlings for out-planting purpose, it is important to choose large seed from a superior source.

Pengaruh Inokulasi Bakteri Endofit dan Ekoenzim Terhadap Pertumbuhan Bibit Kayu Kuku (Pericopsis mooniana Thw.)

Improving the physical quality of kayu kuku seedlings can be done by applying endophytic bacteria and ec-enzymes. The aims of this study were to examine (1) the effect of inoculation of endophytic bacteria on the germination of kuku wood seeds, and (2) the effect of inoculation and application of eco-enzymes on the growth of kuku wood seedlings. The endophytic bacteria were isolated from the shoot of Shorea balangeran plant with the codes SBP 1, SBP 2, and SBP 19. Bacterial application was conducted on seeds and seedlings, while eco-enzyme application was only conducted on kayu kuku seedlings. The results of the research at the seed level showed that inoculation of the endophytic bacteria SBP 19 could accelerate the germination rate of kayu kuku seeds. At the seedling level, inoculation of endophytic bacteria SBP 1, SBP 2, SBP 19 and application of eco-enzymes had no significant effect on height, diameter, number of new leaves, total fresh weight and total dry weight of kayu kuku seedlings. The shoot root ratio of kayu kuku seedlings ranged from 2.66-5.04 and the seedlings quality index ranged from 0.41-0.93, indicating that the seedlings were ready to be transplanted into the field. In general, inoculation of endophytic bacteria had a significant effect on kayu kuku seed germination, but had not been able to increase the growth of kayu kuku seedlings during the 14 weeks of observation.&#x0D; Keywords: Pericopsis mooniana Thw., seed dormancy, seed germination, seedling quality index, shoot root ratio

Influence of leaf area on clonal propagation by mini-cuttings of two varieties of Ficus benjamina L.

Due to the peculiar characteristics of the species Ficus benjamina L., this plant is used on a large scale in afforestation for ornamental purposes and thermal comfort. However, its multiplication depends on clonal propagation techniques, due to the impossibility of obtaining viable seeds for seminal propagation in the semi-arid region. The leaf area rate that must be maintained in the multiplication propagules is a very important factor for the production of quality seedlings, as it influences the initiation and rooting of the species. Therefore, this research aimed to evaluate the influence of different degrees of leaf reduction on minicuttings of two varieties of Ficus benjamina L.. In order to obtain vegetative propagules for the installation of the experiments, a mini-clonal Hedge was established for each variety. The minicuttings were made up with 10 cm in length and the levels of leaf area reduction evaluated were three whole leaves, three leaves reduced to 1/2 and three leaves reduced to 1/3. Ten weeks after planting, the minicuttings were transferred from the rooting environment to the shade house and at sixteen weeks the experiment was finalized. For each variety, an experiment was installed in a Completely Randomized Design (CRD) with three treatments, three replications and plots consisting of twelve mini-cuttings, resulting in an experiment for each variety consisting of 108 mini-cuttings. At seven and sixteen weeks, survival data were analyzed and at the end of the experiment, rooting and aggregation of roots in the substrate. Weekly, up to sixteen weeks, data were collected from roots observed in the extremity of the tube. Regardless of the variety, the leaf area of the mini-cuttings that presented the best results for the clonal propagation of the species Ficus benjamina L., was the ones using mini-cuttings with leaf area reduced to three whole leaves.

Fall fertilization during nursery production increases nitrogen status of Purshia tridentata seedlings: implications for outplanting

During container nursery production of Purshia tridentata (antelope bitterbrush), we found that three fall fertilization applications successfully loaded plants with nitrogen (N) with little effect on plant biomass. Using 15N‐labeled fertilizer to track N movements, we observed that N‐loaded seedlings attained luxury consumption and ultimately translocated more N toward roots. In trees, such N‐loading efforts have been reported to increase seedling survival and growth after outplanting by improving initial root growth. This leads to enhanced access to water and nutrients that increases overall plant competitiveness and performance. Our results add, in general, to the paucity of information concerning fall fertilization of shrubs, and specifically that this technique offers promise to enhance the quality of antelope bitterbrush seedlings. This could improve overall planting success of this important shrub native to western United States rangelands. Increasing the effectiveness of planting antelope bitterbrush, which can often improve restoration trajectories more than direct seeding or reliance on natural regeneration of this species, could accelerate the pace and scope of critical habitat restoration. Restoration is needed as antelope bitterbrush abundance has been reduced across the landscape because of conversion to agriculture, invasion by nonnative annual grasses, and an increase in fire frequency and intensity, among other reasons. In addition, this species provides browse for ungulates and critical habitat for at‐risk species, such as Centrocercus urophasianus (greater sage‐grouse). Although N loading antelope bitterbrush has potential to improve outplanting performance, the resulting higher nutrient status of this preferred browse species may lead to elevated browsing during seedling establishment.

Source-Sink Alterations in Rice Fallow Adaptive Blackgram Variety ADT3 for Enhancement of Yield and Quality of Seed

Seed Production of rice fallow blackgram variety, ADT3 has limitations due to inherent issues of soil fertility, climate change and thermo sensitivity results in poor flowering, reduced pod setting and poor seed filling. Macro and micro nutrients application during critical stages of growth were tried to improve the seed yield and quality in rice fallow blackgram variety ADT3. The combined foliar spraying of 0.5% NPK (macro) and 0.2% chelated micro nutrients mixture (Fe 2.5%, Mn 1.0%, Zn 3.0%, Cu 1.0%, Mo 0.1% and B 0.5%), were sprayed on 15th (Vegetative phase), 30th (Reproductive phase), 45th ( Flowering and pod formation phase) days after germination improved the growth and seed parameters viz., plant height, number of branches, number of pods per plant, number of seeds per pod, filled seed % which resulted in increased seed yield in rice fallow blackgram variety, ADT3.&#x0D; Response of macro and micro nutrients through foliar mode revealed the lack of soil fertility resulting in poor uptake of macro and micro nutrients. Foliar application induced uniform flowering and synchronous maturity of pods with least shattering which would facilitate mechanical harvesting. Foliar application of macro and micro nutrients phenotypically altered the source-sink which greatly influenced the yield of seed, germination and seedling quality parameters.

Industrial Propagation of &amp;lt;i&amp;gt;Coffea&amp;lt;/i&amp;gt; SP. by Bioreactor Technique

Study is carried out at National Key Lab of Plant Cell Biotechnology, Ho Chi Minh City, Vietnam. Vietnam has planning to re-culture of coffea plant in area of over 40.000ha in South of Vietnam. Good quality of seedlings have a big demand. Using bioreactor technique is the first method to resolve the lack of seedlings. Stem, leaves of in vitro plantlets were used as planting materials. Somatic embryo callus was initiated on medium supplemented with MS+ BA (0.1mg/l) + 2iP (2mg/l) + IBA (2mg/l). Somatic cell suspension was created and proliferated on medium MS + kinetin (1mg/l) + BA (0.1mg/l) + 2iP (2mg/l) + 2.4D (1mg/l). Embryogenic suspension was stimulated on the medium MS + kinetin (1mg/l) + BA (4mg/l). In vitro shoots of coffee were regeneration on the medium MS + kinetin (1mg/l) + BA (4mg/l) + Adenin sulfate (40mg/l). Plantlets were enhanced growth and development in immersion-bioreactor cultivation by sinking/rising floated 1min/6hrs. Temperature, light intensity and stirring in stirring-bioreactor cultivation were favoured at 26±2°C, 11.1-22.2μmol/m²/s, and 30rpm. Micropropagation of <i>coffea</i> sp. by bioreactor technique was set up to produce 25,260 plantlets per liter of somatic embryogenesis suspension.

Rhizobium Grants the Reduction of Phosphate Fertilization during the Production of Coffee Seedlings

The use of bacterial inoculants is an attractive alternative that could reduce the consumption of chemical fertilizers in crops. In the production system of quality coffee seedlings, it is essential to achieve an adequate balance of nutrients that allows for healthy plants that are resistant to subsequent handling. The objective of this work was to evaluate the effect of Rhizobium sp. inoculation on the growth, nutrition and quality of coffee seedlings cultivated with different doses of phosphoric fertilization. Inoculation tests were carried out under nursery conditions using Coffea arabica L. cv. “Isla 5–15” and Coffea canephora Pierre ex Froehner cv. “Robusta” seeds inoculated with the Rhizobium sp. Rpr2 strain. Sixty days after sowing, the hypocotyldonal graft was performed, and the resulting plants were also treated with the bacterial inoculant. Plants were then planted in substrate with different doses of phosphorus (P): 25, 50, 75 and 100%. At seven months of cultivation, variables of growth (plant height, stem diameter, number of leaf pairs, main root length, root volume, dry mass of the aerial part, root and total), phosphoric nutrition (leaf and root P contents) and posture quality index were evaluated. The inoculation stimulated the aerial part (37%), root growth (34%), the quality index of the grafted postures (30%), and phosphorus absorption (42%) and allowed a decrease from 25 to 75% of the mineral fertilizer. For the first time in Cuba, the benefits of rhizobial inoculation on the nutrition and quality of coffee seedlings were demonstrated. The inoculation of grafted coffee seedlings with Rhizobium sp. Rpr2 through the inoculation method proposed in this study can be recommended as a new easy, cost-effective and efficient inoculation approach to obtain additional benefits for coffee growth, improving the absorption of nutritive elements and the quality characteristics of the coffee seedlings.

Growth, nutrition and health of coffee seedlings grown with increasing limestone doses in the substrate

During coffee crop formation, seedlings quality is an essential factor to ensure the plants full development. Applying limestone to the substrate is a common practice to correct acidity, thus increasing nutrient availability. Therefore, we aimed to evaluate the effect of increasing limestone doses in the substrate regarding growth, nutrition, health, and quality of coffee seedlings. The experiment was conducted in the plant nursery at the IFSULDEMINAS – Inconfidentes Campus, with an experimental design in randomized blocks with five replications; the treatments received the following limestone doses per cubic meter of substrate: T1: 0 g; T2: 600 g; T3: 1,200 g; T4: 1,800 g; T5: 3,000 g. After 208 days of sowing, samples were collected for leaf analysis. The growth and quality of the seedlings and their incidence and severity of Cercospora were also evaluated. A statistical difference was found in leaf analysis for nitrogen, potassium, and manganese absorption, with no statistical difference for Cercospora coffeicola leaf spots in all treatments. Therefore, the increasing limestone doses do not influence growth, nutrition, and health of the coffee seedlings of the Mundo Novo 376/4 cultivar.

Application of heat-treated oyster shell powder to induce priming of Theobroma cocoa seedlings plant defense system against Phytophthora megakarya attack

Priming with natural compounds is an interesting alternative for sustainable agriculture to explore the molecular mechanisms associated with the management of diseases caused by soil borne pathogens. The aim of this work was to evaluate the effect of the soil amendment with bio-oyster shell on the stimulation of the cocoa plant defense systems against P. megakarya in the nursery. For this purpose, the potential of bio-oyster shell to stimulate cocoa plant defense mechanisms was evaluated by soil amendment at 1% W/W under greenhouse conditions. After soil amendment, agronomic growth parameters and soil parameters were analyzed. The degree of expression of phytoalexins and defense genes was carried out by UPLC-DAD- HRESI–MS (+) and qRT-PCR analyses, respectively. The results obtained show that soil treatment with these composites improves the sanitary quality of cocoa seedlings in controlled conditions through the stimulation of agronomic growth parameters such as plant height, number of leaves, leaf surface area, and fresh weight of shoot and root. The latter leads to an increase in soil pH by about 32 % as well as the improvement of the nutritional status of the soil by 90%. Moreover, bio-oyster shell soil amendment induces up-regulation of TcPer-1, TcGlu1, TcChiB, and TcMYBPA genes and accumulation of primed metabolites such as flavonols, brevifolin, and isoflavone compounds before and after infection. This stimulation based on biological substances make it possible to pre-immunize cocoa plants against pathogen attacks and would be a good candidate to improve the quality of cocoa seeds in Cameroon.

CHEMICAL CONTROL OF Colletotrichum gloeosporioides ON SEEDLINGS OF SINGLE ASSAI PALM

Anthracnose (Colletotrichum gloeosporioides) is the main disease affecting single assai palm seedlings and, therefore, a limiting factor to the production of quality seedlings. So far, there are no fungicide recommendations for the control of C. gloeosporioides in Euterpe precatoria. Thus, this study aimed to investigate the action of fungicides, such as pyraclostrobin + fluxapyroxad, as a possible alternative for controlling anthracnose in single assai palm seedlings. The experiment was installed in the nursery at Embrapa Acre, in a randomized block design, with seven treatments (0 – 0.155 – 0.187 – 0.218 – 0.250 – 0.281 – 0.312 μl of fungicide), with four replications of five plants. Evaluations were conducted for ten months regarding seedling height, stem diameter, number of leaves, shoot dry mass, root dry mass, total dry mass, and Dickson Quality Index. A visual scale ranging from 1 to 9 was used to assess the severity of the disease. The data were submitted to analysis of variance and regression analysis. Under the study conditions, the application of the active ingredient pyraclostrobin + fluxapyroxad reduced anthracnose severity by an average of 36.94% in single assai palm, providing better quality seedlings in the nursery.

Root frost tolerance, seasonal variation in root growth, and field performance of one-year-old Russian larch seedlings with simulated root freezing damages

ABSTRACT Planting healthy seedlings with optimal growth potential is essential for proper growth and survival in forest regeneration. Assessing the seedling quality prior to planting is therefore important. In this Icelandic study, effects of root damage induced with artificial freezing in young Russian larch seedlings were examined using the root growth capacity method (RGC). Frost tolerance of roots varied during the winter, and root growth in undamaged seedlings fluctuated, indicating seasonal variations in growth rhythm. The LT50 value for root frost tolerance was −13.9°C in late January, but already at −10.6°C (LT10) root damages were severe. After one growing season, shoot elongation was significantly lower in seedlings frozen to −9°C, −13.5°C, and −15.5°C by 23%, 54%, and 72%, respectively, compared with undamaged seedlings. Control seedlings and seedlings frozen to −9°C achieved 100% survival after the first growing season. Survival in seedlings frozen to −13.5°C and −15.5°C was 85% and 27%, respectively. After the second growing season, survival decreased in all frost-damaged seedlings. The ongoing mortality demonstrates the long-lasting effects of planting seedlings with damaged root systems, and the fluctuation in root frost tolerance of young Russian larch seedlings during winter emphasises the need for care when seedlings are moved to outdoor storage.

Nicotinamida e Azospirillum brasilense melhoram a qualidade de mudas de Coffea arábica

ABSTRACT The use of biostimulants in coffee seedlings can promote gains in their growth and quality. Thus, this study aimed to evaluate the growth and quality characteristics of Coffea arabica seedlings under the effect of the nicotinamide and Azospirillum brasilense application. The experimental design was randomized blocks with treatments arranged in a 5 × 2 factorial scheme, with four replicates. The treatments resulted from the use of five doses of nicotinamide (0, 30, 60, 90, and 120 mg L-1 of water) combined with the absence and presence of Azospirillum brasilense applied to Coffea arabica seedlings from Catuaí Vermelho 144 cultivar. Plant height, stem diameter, number of leaves, leaf area, shoot dry mass, root dry mass, plant height:stem diameter ratio, shoot:root dry mass ratio, plant height:shoot dry mass ratio, and Dickson quality index were evaluated. The combined or isolated use of A. brasilense and nicotinamide, up to a dose of 33.5 mg L-1, increased the biometric characteristics and dry mass accumulation. However, using nicotinamide doses between 30 and 61.8 g L-1 increased the quality of Coffea arabica seedlings. The synergistic effect of the use of A. brasilense and nicotinamide was verified for the growth and quality of Coffea arabica seedlings.

Saline stress and salicylic acid on growth and quality of guava ‘Paluma’ seedlings

High salt concentrations affect plant growth and development, making it necessary to use methods to reduce the effects of saline stress. In the light of the above, the growth and seedling quality of guava ‘Paluma’ under water salinity and salicylic acid conditions were evaluated in this experiment. The experiment was conducted in a protected environment. The treatments were obtained by combining the electrical conductivity of irrigation water (0.3, 0.8, 1.9, 3.0, and 3.5 dS m-1) and salicylic acid (0, 0.3, 1.0, 1.7, and 2.0 mol L-1), in the 22 + 2 x 2 + 1 scheme, according to the Central Box Composite matrix, using a randomized block design, with four repetitions and five seedlings per plot. The increase in the electrical conductivity of irrigation water and salicylic acid alone inhibited the growth, biomass accumulation, and quality of the seedlings, with the exception of height, number of leaves, and dry biomass of roots and stem that were stimulated with the acid. Salicylic acid intensified the inhibition of seedling growth and quality under saline stress, but it attenuated the salt effect on biomass accumulation. Guava ‘Paluma’ seedlings are sensitive to salinity, and can be produced with water up to 0.8 dS m-1.

Machine vision-based tomato plug tray missed seeding detection and empty cell replanting

The current tomato plug tray sowing methods are plagued by the issue of missed sowing. Consequently, the detection of missed sowing and empty cells replenishment of tomato plug trays after initial sowing is an important prerequisite to realizing precision sowing of plug trays and improving the quality of plug tray seedlings. This study proposed a machine vision-based information perception method for tomato plug trays to detect missed seeds and replenish empty cells. First, based on a YOLOv5x network model, deep learning training was employed to obtain a detection model for identifying tomato seeds in complex backgrounds of plug trays. Thereafter, the location of the tomato seeds was compared with the coordinate value of the edge of the hole, and the missed holes were detected. Based on the missed cells detection results, the empty cell coordinates were converted into replanting coordinates, and the plug tray conveyor and the replanting suction needle are controlled separately considering the replanting row information to replant the missed cavities row by row. Further, the tomato plug tray missed seeding detection and replenishment device was built and tested at a seedling greenhouse. The results indicated an average detection accuracy of 92.84 % with average detection time per tray of 13.475 s. The success rate of replanting on trays was determined to be 91.7 % with 5 %-20 % misses. In addition, the productivity of the tray was approximately 42.4 trays/h. Thus, the proposed method of detecting and replanting misses in tomato trays can be used to improve the performance of tomato seeding. Moreover, it can be used as a reference to improve the precision and efficiency of tomato seeding in plug trays.