scholarly journals Aggressiveness of Phytophthora cinnamomi in avocado seedlings and effect of pathogen inoculum concentration and substrate flooding periods on root rot and development of the plants

2020 ◽  
Vol 42 (6) ◽  
Author(s):  
Ivan Herman Fischer ◽  
Aloísio Costa Sampaio ◽  
Rosemary Marques de Almeida Bertani ◽  
Bruno Henrique Leite Gonçalves ◽  
Eduardo Feichtenberger
Keyword(s):  
Root Rot ◽  
Phytophthora Cinnamomi ◽  
Dry Mass ◽  
Area Index ◽  
Inoculum Concentration ◽  
Disease Symptoms ◽  
Two Factors ◽  
Number Of Leaves ◽  
Collar Diameter ◽  
Soilless Substrate

Abstract The present study evaluated the aggressiveness of Phytophthora cinnamomi isolates and the effect of pathogen inoculum concentration and periods of substrate flooding on root rot and plant development. Twelve pathogen isolates were inoculated on the collar region of avocado seedlings with or without wounding. Only 31.3% of the inoculated plants without wounding developed lesions, compared to 100% of the plants with wounding, while the isolates showed different aggressiveness levels. Avocado seedlings had their substrate inoculated with 0, 0.1% and 1.0% (m/v) wheat seeds colonized by the pathogen per pot, and four periods of 0, 12 and 24 h substrate flooding were produced at fortnightly intervals. The assessed parameters were number of leaves per plant, collar diameter, plant height, leaf area index, visual severity percentage of infected roots, fresh mass (%) of diseased roots and dry mass of shoot and roots. Both pathogen inoculation and substrate flooding caused root rot; however, combination of these two factors produced an additional effect on disease symptoms. Root rot severity was superior to 50% when soilless substrate had 0.1% (m/v) P. cinnamomi inoculum and flooded for 12-24 h after inoculation, conditions that can be recommended for pathogenicity and disease control studies using potted avocado plants.

scholarly journals Trichoderma Contributes to the Germination and Seedling Development of Açaí Palm

Agriculture ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 456
Author(s):  
Bruno Fróes Campos ◽  
Anselmo Junior Corrêa Araújo ◽  
Cristina Aledi Felsemburgh ◽  
Thiago Almeida Vieira ◽  
Denise Castro Lustosa
Keyword(s):  
Dry Mass ◽  
Initial Growth ◽  
Randomized Design ◽  
Trichoderma Isolate ◽  
Number Of Leaves ◽  
Collar Diameter ◽  
Completely Randomized Design ◽  
Set Up ◽  
Root Size ◽  
Trichoderma Isolates

The application of Trichoderma fungus can be used to obtain seedlings of higher quality for plantations. The objective of this study was to evaluate the effects of Trichoderma isolates on the germination and initial growth of açaí seedlings. Two trials were set up. In the laboratory, the seeds were inoculated in suspensions prepared with each of the isolates for 24 h, and they were arranged in trays containing filter paper in a completely randomized design with five replicates containing 50 seeds each. For the control, the seeds were submerged only in water. Part of the seedlings resulting from seeds treated and not treated with Trichoderma were transferred to bags containing forest soil and were submitted to seven modes of application of Trichoderma and kept in a nursery. The speed of germination and hypocotyl were not influenced by the biological treatment. The application of the different Trichoderma isolates positively influenced the height, collar diameter, number of leaves, root size, leaf area and root, and aerial part dry mass of the açaí seedlings. The application of the Trichoderma isolate TAM01 on the preplanting substrate and biweekly applications on the postplanting substrate was the combination that most positively influenced the development of açai seedlings.

scholarly journals Efficiency of nitrogen and potassium application on phytotechnical parameters and yield of melon

2020 ◽  
Vol 36 ◽  
Author(s):  
Pablo Cristovão de Alencar Fernandes ◽  
Laércio da Silva Pereira ◽  
Carlos José Gonçalves de Souza Lima ◽  
Gabriel Barbosa da Silva Júnior ◽  
Theuldes Oldenrique da Silva Santos ◽  
...  
Keyword(s):  
Block Design ◽  
Branch Length ◽  
Biomass Accumulation ◽  
Area Index ◽  
Leaf Chlorophyll ◽  
Technological Level ◽  
Rational Management ◽  
Number Of Leaves ◽  
Use Efficiency ◽  
Collar Diameter

Phytotechnical parameters, yield and fertilizer use efficiency are relevant to the rational management of fertigation, especially in cultivation of high technological level. Thus, the objective was to evaluate the influence and efficiency of nitrogen (N) and potassium (K) application on the phytotechnical parameters, yield and nutritional efficiency of yellow melon in a fertigation system. The experiment was conducted in the city of Bom Jesus-PI, Brazil, from January to April 2016, in a strip-block design with four replicates, and the treatments consisted of five N levels (0, 45, 90, 135 and 180 kg ha-1 in the form of urea) and five K levels (0, 60, 120, 180 and 240 kg ha-1 in the form of potassium chloride), applied through fertigation. Collar diameter, main branch length, leaf chlorophyll content, number of leaves, leaf area index, biomass accumulation, fruit yield, and N and K use efficiencies were evaluated. Applications of 180 kg ha-1 of N and 240 kg ha-1 of K, respectively, led to the highest growth of the melon, while maximum production was obtained with the use of 112.50 and 165 kg ha-1 of N and K, respectively. The efficiency of N and K use decreased with increasing levels.

scholarly journals The production of Physalis spp. seedlings grown under different-colored shade nets

2016 ◽  
Vol 38 (2) ◽  
pp. 257 ◽  
Author(s):  
Daniel Fernandes da Silva ◽  
Rafael Pio ◽  
Joyce Dória Rodrigues Soares ◽  
Paulyene Vieira Nogueira ◽  
Pedro Maranha Peche ◽  
...  
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Block Design ◽  
Dry Mass ◽  
Additional Treatment ◽  
Light Spectrum ◽  
Treatment Control ◽  
Area Index ◽  
Randomized Block Design ◽  
Number Of Leaves

The objective of this study was to evaluate the production of seedlings of Physalis L. species under different-colored shade nets. Four shade nets individually stained white, blue, red and black, all with 50% shading, were used in this study, and an additional  treatment (control) was used in which seedlings were grown in full sun. The study examined four species of Physalis, namely, P. peruviana, P. pubescens, P. minima and P. ixocarpa. The experiment followed a randomized block design with three blocks and 25 seeds per plot. The species were sown in styrofoam trays. Germination was monitored daily to calculate the Emergency Velocity Index (EVI) and stabilize the overall percentage of emergence. Height, stem diameter, number of leaves, leaf area index and dry mass of seedlings were assessed at 50 days after sowing. The study found that these species react differently to changes in the light spectrum. Seedlings of P. peruviana should be grown under a white or red shade net; of P. pubescens under a white or black shade net; of P. minima under a white, red or black shade net; and of P. ixocarpa under a white shade net. For all species, 50% shade should be used. 

scholarly journals Environment and slow-release fertilizer in the production of Euterpe precatoria seedlings

2018 ◽  
Vol 48 (4) ◽  
pp. 382-389
Author(s):  
Ueliton Oliveira de Almeida ◽  
Romeu de Carvalho Andrade Neto ◽  
Aureny Maria Pereira Lunz ◽  
Sônia Regina Nogueira ◽  
David Aquino da Costa ◽  
...  
Keyword(s):  
Slow Release ◽  
Block Design ◽  
Dry Mass ◽  
Palm Tree ◽  
Slow Release Fertilizer ◽  
Lack Of Information ◽  
Randomized Block Design ◽  
Number Of Leaves ◽  
Collar Diameter ◽  
Root Collar

ABSTRACT Euterpe precatoria Mart. has been demanded due to the functional characteristics of its fruits and, therefore, its planting has been encouraged. However, there is a lack of information about the seedling production system of this palm tree. Neither a favorable environment nor the amount of fertilizer in the substrate have been defined for the production of healthy and vigorous seedlings. This study aimed to evaluate the effect of environments and doses of a slow-release fertilizer on the production of E. precatoria seedlings. The experiment was conducted in a randomized block design, with three replications and ten plants per plot. The treatments were arranged in a 4 x 5 factorial scheme, with four environments (under shading levels of 20 %, 30 %, 50 % and 75 %) and five doses of a slow-release fertilizer (0.0 kg m-3, 2.5 kg m-3, 5.0 kg m-3, 7.5 kg m-3 and 10.0 kg m-3 of substrate). The seedling height; root collar diameter; number of leaves; leaf, shoot, root and total dry mass; and the Dickson quality index were analyzed. There were significant interactions between the shaded environments and slow-release fertilizer doses for all the analyzed variables. The 75 %-shaded environment yielded better quality seedlings. The slow-release fertilizer can be used to produce E. precatoria seedlings in environments under shading levels of 50 % and 75 %, being the 4.60 kg m-3 and 8 kg m-3 doses, respectively, the most recommended ones.

scholarly journals Tratamentos Pré-Germinativos na Emergência e Desenvolvimento Inicial de Plântulas de Graviola

2021 ◽  
Vol 25 (1) ◽  
pp. 72-76
Author(s):  
Marcus Vinicius Sandoval Paixão ◽  
Andrieli Ferrari Mônico ◽  
Rafaela Barreto Cazaroto Grobério ◽  
Gustavo Miranda Cremonini ◽  
Hélio Pena de Faria Junior ◽  
...  
Keyword(s):  
Seedling Emergence ◽  
Dry Mass ◽  
Experimental Unit ◽  
Annona Muricata ◽  
Initial Development ◽  
Efficient Treatment ◽  
Green Mass ◽  
Leaf Dry Mass ◽  
Number Of Leaves ◽  
Collar Diameter

A graviola, Annona muricata L., produz sementes que podem apresentar dormência ocasionada pela impermeabilidade do tegumento à água, necessitando assim de métodos para superação desta. Objetivou-se avaliar o efeito de tratamentos pré-germinativos na emergência e desenvolvimento inicial de plântulas de graviola. O delineamento experimental utilizado foi em blocos ao acaso, com 13 tratamentos e quatro repetições, sendo cada unidade experimental composta de 50 sementes. As sementes foram submetidas aos tratamentos com imersão por 30 minutos, os quais foram: água (26 °C testemunha), solução de giberelina a 1.000, 2.000, 3.000 e 4.000 mg.L-1, água com gelo em ponto de fusão (0 °C), congelador por 6 horas (-10 °C), geladeira por 24 horas (10 °C), água em ponto de ebulição (100 °C), solução de NaCl 9 g.L-1, solução de KCl 5 g.L-1, água de coco e suco de laranja. A semeadura ocorreu em tubetes 280 mL contendo substrato composto por solo+eterco bovino. Trinta dias após a semeadura (DAS) avaliou-se a porcentagem, índice de velocidade e tempo médio de emergência das plântulas. Sessenta dias após a semeadura foram avaliados: número de folhas; altura da planta; diâmetro do coleto; comprimento da raiz; massa verde foliar; massa seca foliar; massa verde e massa seca da raiz. O tratamento com giberelina de 4.000 mg.L-1 de GA3 foi o tratamento mais eficiente para induzir a emergência e desenvolvimento inicial de plântulas de graviola.   Palavras-chave: Annona muricata. Giberelina. Propagação.   Abstract Soursop, Annona muricata L., produces seeds that may present dormancy caused by the impermeability of the integument to water, thus requiring methods to overcome it. The objective was to evaluate the effect of pre-germinative treatments on the emergence and initial development of soursop seedlings. The experimental design used was in randomized blocks, with 13 treatments and four replications, each experimental unit consisting of 50 seeds. The seeds were submitted to immersion treatments for 30 minutes, which were: water (26°C control), 1.000 gibberellin solution, 2.000, 3.000 e 4.000 mg.L-1, water with ice at melting point (0 °C), freezer for 6 hours (-10 °C), refrigerator for 24 hours (10 °C), boiling water (100°C), NaCl 9 g.L-1 solution, KCl 5 g.L-1 solution, coconut water and orange juice. Sowing took place in 280 mL tubes containing substrate composed of soil + bovine manure. Thirty days after sowing (DAS), the percentage, speed index and mean seedling emergence time were evaluated. Sixty days after sowing the following items were evaluated: number of leaves; plant height; collar diameter; root length; leaf green mass; leaf dry mass; green mass and dry mass of the root. The treatment with gibberellin of 4.000 mg.L-1 of GA3 was the most efficient treatment to induce the emergence and initial development of soursop seedlings.   Keywords: Annona muricate. Gibberellin.  Propagation.

scholarly journals Germination and vigor of seeds of Magonia pubescens A. St.-Hil. submitted to storage and pre-imbibition in water

2017 ◽  
Vol 39 (4) ◽  
pp. 344-352
Author(s):  
Cárita Rodrigues de Aquino Arantes ◽  
Carmen Lúcia Ferreira Fava ◽  
Elisangela Clarete Camili ◽  
Walcylene Lacerda Matos Pereira Scaramuzza
Keyword(s):  
Seed Size ◽  
Dry Mass ◽  
Germination Percentage ◽  
Shoot Height ◽  
Germination Time ◽  
Mean Germination Time ◽  
Number Of Leaves ◽  
Collar Diameter ◽  
The Mean ◽  
Storage Times

Abstract: Timbó (Magonia pubescens A. St.-Hil.) is a species with ornamental potential, which can be used in composition of gardens, squares and especially in streets landscaping. It is also suitable for planting in degraded areas of permanent preservation. This work aimed to verify the effect of seed size, storage and pre-imbibition time on seed germination and vigor. The test design was completely randomized, in a plot scheme subdivided in time. The main plots were seed size (large and small), packaging (0.5 mm-thick transparent polyethylene and kraft paper bag), and time of imbibition in water (0, 12 and 24 hours); and as subplots, it was considerate the storage times (0, 3, 6, 9 and 12 months). The tests were carried out in five replications of ten seeds, and the evaluated variables were: water content of the seeds, percentage of germination (% G), mean germination time (MGT), shoot height (cm), collar diameter (mm), number of leaves, and fresh and dry mass of the aerial part (g). The size of the seed did not influence the germination percentage, but large seeds formed more vigorous seedlings. The storage did not affect seeds germination, nor the vigor of the seedlings. Seed pre-imbibition did not influence the percentage of germination, but the mean germination time decreased, and more vigorous seedlings were formed. In order to obtain more vigorous Timbó seedlings, the best option is to use large seeds. They can be stored for up to 12 months without losing vigor and pre-soaked to accelerate the beginning of germination, thus forming a more homogeneous lot of seedlings.

PENGARUH KOMPOS SAMPAH KOTA DAN PUPUK KANDANG SAPI TERHADAP PERTUMBUHAN DAN HASIL TANAMAN PAKCOY (BRASSICA RAPA, L. CHINENSIS) PADA ALUVIAL KABUPATEN INDRAMAYU

2018 ◽  
Vol 9 (2) ◽  
pp. 153-163
Author(s):  
Wiwik Ambarsari ◽  
Henly Yuliana
Keyword(s):  
Plant Height ◽  
Brassica Rapa ◽  
Block Design ◽  
Cattle Manure ◽  
Growth And Yield ◽  
Randomized Block Design ◽  
Two Factors ◽  
Number Of Leaves ◽  
Experimental Garden

The study aimed to determine the effect of the combination of city waste compost and cattle manure on the growth and yield of pakcoy plants (Brassica rapa, L. Chinensis) in Aluvial, Indramayu Regency. The study was conducted at the Experimental Garden of the Faculty of Agriculture, Wiralodra University, Indramayu Regency from March to August 2018. This study used Factorial Pattern Randomized Block Design with two factors. The first factor is city waste compost and the second factor is cattle manure with 4 levels: 0%, 3.0%, 6.0%, and 9.0%, repeated twice. The results showed that there was an independent influence between city waste compost and cattle manure on plant height and number of leaves. The best combination to increase the feasibility weight of pakcoy consumption is by giving city waste compost 9.0% (S4) and cattle manure 6.0% (K3).

scholarly journals Cellulase Activity as a Mechanism for Suppression of Phytophthora Root Rot in Mulches

2011 ◽  
Vol 101 (2) ◽  
pp. 223-230 ◽  
Author(s):  
Brantlee Spakes Richter ◽  
Kelly Ivors ◽  
Wei Shi ◽  
D. M. Benson
Keyword(s):  
Root Rot ◽  
Phytophthora Cinnamomi ◽  
Cellulase Activity ◽  
Enzyme Concentration ◽  
Disease Suppression ◽  
In Vitro Assays ◽  
Infested Soil ◽  
Phytophthora Root Rot ◽  
Standard Curve

Wood-based mulches are used in avocado production and are being tested on Fraser fir for reduction of Phytophthora root rot, caused by Phytophthora cinnamomi. Research with avocado has suggested a role of microbial cellulase enzymes in pathogen suppression through effects on the cellulosic cell walls of Phytophthora. This work was conducted to determine whether cellulase activity could account for disease suppression in mulch systems. A standard curve was developed to correlate cellulase activity in mulches with concentrations of a cellulase product. Based on this curve, cellulase activity in mulch samples was equivalent to a cellulase enzyme concentration of 25 U ml–1 or greater of product. Sustained exposure of P. cinnamomi to cellulase at 10 to 50 U ml–1 significantly reduced sporangia production, but biomass was only reduced with concentrations over 100 U ml–1. In a lupine bioassay, cellulase was applied to infested soil at 100 or 1,000 U ml–1 with three timings. Cellulase activity diminished by 47% between 1 and 15 days after application. Cellulase applied at 100 U ml–1 2 weeks before planting yielded activity of 20.08 μmol glucose equivalents per gram of soil water (GE g–1 aq) at planting, a level equivalent to mulch samples. Cellulase activity at planting ranged from 3.35 to 48.67 μmol GE g–1 aq, but no treatment significantly affected disease progress. Based on in vitro assays, cellulase activity in mulch was sufficient to impair sporangia production of P. cinnamomi, but not always sufficient to impact vegetative biomass.

scholarly journals Phytophthora mediterranea sp. nov., a New Species Closely Related to Phytophthora cinnamomi from Nursery Plants of Myrtus communis in Italy

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 682
Author(s):  
Carlo Bregant ◽  
Antonio A. Mulas ◽  
Giovanni Rossetto ◽  
Antonio Deidda ◽  
Lucia Maddau ◽  
...  
Keyword(s):  
New Species ◽  
Root Rot ◽  
Phytophthora Cinnamomi ◽  
Colony Growth ◽  
Phytophthora Species ◽  
Maximum Temperature ◽  
Pathogenicity Test ◽  
Forest Nurseries ◽  
Collar And Root Rot ◽  
A New Species

Monitoring surveys of Phytophthora related diseases in four forest nurseries in Italy revealed the occurrence of fourteen Phytophthora species to be associated with collar and root rot on fourteen plants typical of Mediterranean and alpine regions. In addition, a multilocus phylogeny analysis based on nuclear ITS and ß-tubulin and mitochondrial cox1 sequences, as well as micromorphological features, supported the description of a new species belonging to the phylogenetic clade 7c, Phytophthora mediterranea sp. nov. Phytophthora mediterranea was shown to be associated with collar and root rot symptoms on myrtle seedlings. Phylogenetically, P. mediterranea is closely related to P. cinnamomi but the two species differ in 87 nucleotides in the three studied DNA regions. Morphologically P. mediterranea can be easily distinguished from P. cinnamomi on the basis of its smaller sporangia, colony growth pattern and higher optimum and maximum temperature values. Data from the pathogenicity test showed that P. mediterranea has the potential to threaten the native Mediterranean maquis vegetation. Finally, the discovery of P. cinnamomi in alpine nurseries, confirms the progressive expansion of this species towards cold environments, probably driven by climate change.

Variability and inheritance in macadamia progenies to Phytophthora cinnamomi and P. multivora the causal agents of root rot and stem canker

2021 ◽  
Author(s):  
Olumide S. Jeff-Ego ◽  
Andre Drenth ◽  
Bruce Topp ◽  
Juliane Henderson ◽  
Olufemi A. Akinsanmi
Keyword(s):  
Root Rot ◽  
Phytophthora Cinnamomi ◽  
Stem Canker
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