Clonal Seedlings Research Articles

Effects of defoliation on the development of clonal seedlings of Tectona grandis L.f

Objetivo: O objetivo deste estudo é investigar analisar as consequências das desfolhas artificiais, de 0%, 25%, 50%, 75% e 100% na estratégia de desenvolvimento em mudas clonais de Tectona grandis. Referencial Teórico: A produção de teca vem aumentando no Brasil em paralelo aos estudos para a seleção de melhores materiais genéticos em experimentos de campo, porém se forem considerados o seu comportamento após danos causados em situações reais de campo, possibilitará uma melhor seleção e produtividade do plantio. Método: Os testes foram realizados em sete clones, utilizando-se mudas com dois meses de plantio em vasos de 10 L, avaliados até 75 dias após as desfolhas. Para a análise de danos foram coletados dados da altura (cm), do diâmetro do coleto (mm), mensalmente, e da matéria seca (g) ao final do experimento. Posteriormente, foram avaliadas as consequências na qualidade das mudas através da razão da massa seca da parte aérea e massa seca da parte radicular e a estabilidade do comportamento genético entre os testes de desfolha. Resultados e Discussão: Os materiais genéticos tiveram resultados distintos, desde perda até estímulo no desenvolvimento das partes da planta. A análise da parte aérea da planta é insuficiente para identificar as consequências da desfolha. Os clones que apresentaram maior estabilidade comportamental genética, obtiveram resultados mais significativos estatisticamente em relação à testemunha. Implicações da Pesquisa: As mudas que foram submetidas ao maior percentual de desfolha não foram obrigatoriamente as que sofreram maior perda de incremento. Originalidade/Valor: Este estudo contribui para a literatura por apresentar as qualidades e instabilidades dos clones replicados de matrizes de Tectona grandis. A relevância e o valor desta pesquisa são evidenciados pelos resultados serem distintos nos materiais genéticos da mesma espécie quando induzidos a um estresse.

Rooting Conditions for Production of Guarana Clonal Seedlings

The guaraná tree is a species known for the stimulating properties found in its seeds, leading to increased consumption and promising production. Cultivation is primarily carried out in family farming systems, and one of the challenges in the production process is the acquisition of seedlings. The conventional nursery system, which employs intermittent misting for the production of guaraná clones, raises the cost of seedlings, necessitating the exploration of alternatives to this approach. The aim of this study was to evaluate different conditions as alternatives to the conventional nursery system for rooting guaraná cuttings. The experimental design was entirely randomized, featuring three guaraná genotypes, BRS Maués, BRS CG 611, and BRS Luzeia, alongside two rooting conditions, the conventional nursery and a humid chamber with nebulization, with four repetitions. The rooting of guaraná clones was significantly influenced by the interaction between conditions and genotypes. The humid chamber with nebulization demonstrated superior root system characteristics among the tested conditions, with a rooting rate of 56.66% for BRS Luzeia. This method proved to be efficient and accessible for small producers, making it a satisfactory option for rooting guaraná trees.

Silicon attenuates nutritional disorder of phosphorus in seedlings of Eucalyptus grandis × Eucalyptus urophylla

BackgroundNutritional disorders of phosphorus (P), due to deficiency or toxicity, reduce the development of Eucalyptus spp. seedlings. Phosphorus deficiency often results in stunted growth and reduced vigor, while phosphorus toxicity can lead to nutrient imbalances and decreased physiological function. These sensitivities highlight the need for precise management of P levels in cultivation practices. The use of the beneficial element silicon (Si) has shown promising results under nutritional stress; nevertheless, comprehensive studies on its effects on Eucalyptus spp. seedlings are still emerging. To further elucidate the role of Si under varying P conditions, an experiment was conducted with clonal seedlings of a hybrid Eucalyptus spp. (Eucalyptus grandis × Eucalyptus urophylla, A207) in a soilless cultivation system. Seedlings were propagated using the minicutting method in vermiculite-filled tubes, followed by treatment with a nutrient solution at three P concentrations: a deficient dose (0.1 mM), an adequate dose (1.0 mM) and an excessive dose (10 mM), with and without the addition of Si (2mM). This study assessed P and Si concentration, nutritional efficiency, oxidative metabolism, photosynthetic parameters, and dry matter production.ResultsSi supply increased phenolic compounds production and reduced electrolyte leakage in seedlings provided with 0.1 mM of P. On the other hand, Si favored quantum efficiency of photosystem II as well as chlorophyll a content in seedlings supplemented with 10 mM of P. In general, Si attenuates P nutritional disorder by reducing the oxidative stress, favoring the non-enzymatic antioxidant system and photosynthetic parameters in seedlings of Eucalyptus grandis × Eucalyptus urophylla.ConclusionThe results of this study indicate that Eucalyptus grandis × Eucalyptus urophylla seedlings are sensitive to P deficiency and toxicity and Si has shown a beneficial effect, attenuating P nutritional disorder by reducing the oxidative stress, favoring the non-enzymatic antioxidant system and photosynthetic parameters.

Assessment of Drought Adaptation in Hevea Brasiliensis PB 260 Clone Seedlings During El Nino Events

Assessment of Drought Adaptation in Hevea Brasiliensis PB 260 Clone Seedlings During El Nino Events

Influence of Drought Stress and Foliar Application of Salicylic Acid on Early Vegetative Stage of Cacao

Cacao (Theobroma cacao L.) is noted to have a low tolerance to drought and is, therefore, not resilient to prolonged dry periods. The study sought to evaluate the morpho-anatomical and physiological responses of two clonal seedlings of cacao BR25 and K9 under drought stress and to explore the potential alleviating effects of salicylic acid (SA) at concentrations of 0.5 and 1.0 mM on the early vegetative stage. Eleven-month-old BR25 and K9 cacao were pre-treated with foliar application of 0.5 and 1.0-mM SA for 2 wk before the onset of drought conditions. Well-watered and drought seedlings with no pre-treatments served as the control. Water was withheld for 20 d, after which rewatering resumed for 3 mo. Results revealed that after 20 d of drought, both clonal varieties experienced a significant decline in relative water content (RWC) and increased ascorbate peroxidase (APX) and catalase activity. Changes in stem diameter were observed after a rewatering period of 3 mo. K9 exhibited a noticeable reduction in root and shoot dry weight and stomatal aperture after 20 d of drought, whereas BR25 showed a decrease in total chlorophyll content and chlorophylls a and b. Furthermore, the results of the study suggest that 0.5-mM SA has the potential to mitigate the drastic effects during drought in BR25 and K9 cacao by improving RWC, stomatal length, and width. On the other hand, 1.0- mM SA has the potential to alleviate the effects of drought experienced earlier on by improving root dry weight and APX activities of the seedlings.

Evaluation of survival, growth, and phytoremediation potential of Populus and Salix seedlings grown in polluted soils

The aim of this thesis was to evaluate the survival, growth, and phytoremediation potential of Populus and Salix seedlings grown in polluted soils. More specifically, the following topics were studied: (1) the survival and growth of two European aspen clones and four hybrid aspen clones grown in control soil (pristine), old creosote soil polluted with hydrocarbons, and pristine soil spiked with fresh diesel oil at three different planting densities in a greenhouse over two growing seasons (Article I); (2) the survival, growth, and hydrocarbon removal of three European aspen clones and seven hybrid aspen clones grown in hydrocarbon-contaminated soil (including polycyclic aromatic hydrocarbons (PAHs) and total petroleum hydrocarbons (TPHs)) under field conditions over 4 years (Article II); and (3) the growth and metal accumulation ability of Salix psammophila seedlings with bamboo biochar (BBC) amendment at ratios of 0–7% in soils heavily contaminated by Cd and Zn in a pot experiment over 180 days (Article III). In study I (Article I), the survival rates of European aspen and hybrid aspen clone seedlings were 70–100% in control soil, 99% in the old creosote-contaminated soil, and 22–59% in the diesel-contaminated soil across all planting densities. The heights of aspen seedlings were 5–44% and 9–38% lower and the stem dry biomass was 9–93% and 34–63% lower in diesel-contaminated and creosote-contaminated soils, respectively, compared to the control. Low plant density increased survival rates and growth compared to higher density treatments. Of all the clones, hybrid aspen clones 14 and 291 and European aspen clone R3 showed reasonable survival and growth across all treatments. Soil treatment, planting density, and clone type significantly affected survival rate, height, and stem dry biomass (p < 0.05). In study II (Article II), the highest survival rates in old creosote-contaminated soils were in clone 291 (72%) among hybrid aspen clones and clone R3 (70%) among European aspen clones. Hybrid aspen clones 14 and 34 had 16–211% greater heights than other hybrid aspen clones. The height of European aspen clone R3 was also 25‒35% greater than that of other European aspen clones. However, clone type did not significantly affect seedling survival or height (p > 0.05). Among hybrid aspen clones, clone 134 had the largest hydrocarbon removal at a depth of 5–10 cm and clone 191 at a depth of 10–50 cm. Clone 14 also showed potential for removing hydrocarbons at both soil depths. In European aspen clones, clone R2 had the highest hydrocarbon removal at both soil depths. However, all clones showed an ability to remove total PAHs and TPHs from the soil (but p < 0.05 only at a soil depth of 5–10 cm). The reduction in hydrocarbon levels in the soil was more prominent at a soil depth of 5–10 cm than at a depth of 10–50 cm. Based on studies I and II, European aspen and hybrid aspen clones can be considered candidates for the remediation of soils polluted with PAHs and TPHs. In study III (Article III), BBC ratios of 1% and 5% resulted in only slight decreases in characteristics, especially height (0.6‒1.3%) but also total dry biomass (2‒10%), of S. psammophila seedlings compared to the control, whereas BBC 3% increased these measurements slightly (2% increase). BBC 7% reduced the height (16%) and total dry biomass (26%) of seedlings compared to the control. BBC amendment increased the accumulation of Cu, Cd, and Zn in different plant tissues, especially Cd and Zn accumulation (23‒30% and 13‒24%, respectively), in the BBC 3% treatment compared to the control. Based on these findings, S. psammophila with BBC amendment can be considered a candidate for phytoremediation. However, metal accumulation in the roots, stems, and leaves was not significantly affected by the BBC 1‒7% treatments (p > 0.05), except for Pb accumulation in the roots and Cu accumulation in the stem (p < 0.05). Overall, hybrid aspen, European aspen, and S. psammophila seedlings showed reasonable survival and growth, photosynthetic activity, efficient hydrocarbon removal from soil and metal accumulation ability both under greenhouse conditions and in a field experiment. Therefore, these species could be used to depollute areas affected by a range of hydrocarbons or Cd and Zn. However, future research should be conducted in the field to verify the abilities of hybrid and European aspens and S. psammophila to remediate soil contaminated by hydrocarbons, Cd, or Zn, and such studies should also use different planting densities and soil amendments over longer periods.

Size of mini-cuttings for the production of Sarcomphalus joazeiro (Mart.) Hauenshild seedlings

The appropriate size of minicuttings in the clonal propagation of plants by minicutting varies according to the species and must be tested experimentally. In this context, the objective was to evaluate three sizes of minicuttings for the production of clonal seedlings by the minicutting process of the species Sarcomphalus joazeiro (Mart.) Hauenshild. Minicuttings with sizes of 5 cm, 8 cm and 11 cm in length were evaluated for survival, rooting and seedling quality formed by the minicutting technique. According to the results obtained and also taking into account that the smaller the propagule used for clonal propagation, the greater the number of minicuttings are obtained, it is recommended to use minicuttings with a length of 8 cm.

Evaluation and selection of passion fruit progenies resistant to collar rot disease

The objective of this work is to evaluate and select backcrosses of passion fruit progenies resistant to soil diseases. This selection contributes to the improvement of the passion fruit genetic improvement program. A cross of the interspecific hybrid UNEMAT 124-3 resistant to Fusarium solani was carried out. The hybrid arose from crossing the resistant species P. nitida with a commercial cultivar of P. edulis. P. edulis, cultivar BRS Sol do Cerrado, was a recurrent parent. The BC1 resistance tests were evaluated twice. The first test was carried out with BC1 adducts that are in the field; for this, clone seedlings were produced from cuttings of each plant for the resistance test. The second test comprised inoculation directly into BC1s that were planted in pots without replications. In addition, clones of P. nitida and HI were used as a positive (resistant) control and clonal seedlings of P. edulis as a negative (susceptible) control. The evaluation of resistance of the genotypes to F. solani was quantified considering ten resistance variables. In the first trial with plants from cuttings, it was possible to identify the BC1s 02, 14, and 24 as resistant to F. solani. In the second trial with Passiflora spp. seedlings, considering the results of UPGMA, hierarchical methods of torch optimization and graphical dispersion per genotype considering the importance of characters, it was possible to identify the BC1s 25, 26, 27, 28, 31, 43, 45, 48, 53, 57, 58, 61, 63, 66, 68, 71, 72, 73, 74, 80, 81, 83, 84, 86, and 87 as resistant. These should be selected to continue the passion fruit improvement program

Accumulation Capacity of Nickel and Zinc in Yerba Mate Cultivated in Soils with Contrasting Parent Materials.

Yerba mate (Ilex paraguariensis St. Hill.) has shown a relatively high capacity for micronutrient absorption and could be a candidate for biofortification and combating a lack of micronutrients. To further evaluate the accumulation capacity of Ni and Zn, yerba mate clonal seedlings were grown in containers under five rates of Ni or Zn (0, 0.5, 2, 10, and 40mgkg-1) with three soils originating from different parent material (basalt, rhyodacite, and sandstone). After 10months, plants were harvested, divided into component parts (leaves, branches, and roots), and evaluated for 12 elements. The use of Zn and Ni enhanced seedling growth under rhyodacite- and sandstone-derived soils at the first application rate. Application of Zn and Ni resulted in linear increases based on Mehlich I extractions; recovery of Ni was smaller than Zn. Root Ni concentration increased from approximately 20 to 1000mgkg-1 in rhyodacite-derived soil and from 20 to 400mgkg-1 in basalt- and sandstone-derived soils; respective increases in leaf tissue were ~ 3 to 15mgkg-1 and 3 to 10mgkg-1. For Zn, the maximum obtained values were close to 2000, 1000, and 800mgkg-1 for roots, leaves, and branches for rhyodacite-derived soils, respectively. Corresponding values for basalt- and sandstone-derived soils were 500, 400, and 300mgkg-1, respectively. Although yerba mate is not a hyperaccumulator, this species has a relatively high capacity to accumulate Ni and Zn in young tissue with the highest accumulation occurring in roots. Yerba mate showed high potential to be used in biofortification programs for Zn.

ASPECTS OF CLONALMICROPROPAGATION AND CONSERVATION OF PLANTS IN VITRO

Despite more than a century of research on effective biotechnological methods to reproduce various plant species, microclonal reproduction continues to be an important tool for large- scale production. The clonal seedlings of important species maintain genetic fidelity and do not contain pests. In some cases, microclonal propagation is the only method that contributes to the maintenance and economic value of specific agricultural plant species. Microclonal reproduction as a method has solved many phytosanitary problems and has allowed both expansion and access to high-quality plants for producers from different countries and economic conditions, thus effectively contributing to the expansion of agriculture now and in the foreseeable future. Currently, this method is widely used in the creation of planting material for crops for agriculture and cultivation of crops of industrial floriculture, fruit, berry crops and woody plants. Thanks to this method, it is possible to createin vitro banks of rare and valuable plant genotypes. Modern technologies of clonal micro-multiplication are at the stage of industrial flow, which quickly responds to market demands. The analysis of domestic and foreign sources of scientific research on microclonal plant propagation has shown that, at the present time, the cost of its use is quite high and requires the presence of laboratories with appropriate equipment and highly qualified staff. Modification and adaptation of the method of microclonal reproduction of plants contributes to the implementation of the morphogenetic potential, determines the specific features of the source material, the type of explant, its physiological state, the composition of nutrient media, and cultivation conditions.

Effects of different water conditions on the cadmium hyperaccumulation efficiency of Rorippa sylvestris (L.) Besser and Rorippa amphibia Besser.

Increasing the translocation and accumulation of cadmium (Cd) in Cd hyperaccumulator is an important technology to improve the phytoremediation efficiency of Cd-contaminated soil. In order to investigate the effects of different water conditions on the growth and Cd accumulation ability of Cd hyperaccumulators Rorippa sylvestris (L.) Besser and Rorippa amphibia Besser in Cd-polluted soil, clone seedlings of them were transplanted into pots filled with 50mgkg-1 Cd-contaminated soil and cultured with water conditions of soil relative water content (RWC) 35%, 55%, 75%, 95%, and flooding respectively. The results showed the following: with the increase of RWC, the height of R. sylvestris and R. amphibia increased gradually, the dry biomass of shoot and whole plant increased and reached the maximum in 95% and then decreased in flooding; the Cd concentrations in shoots of R. sylvestris and R. amphibia were more than 100mgkg-1 except for 35% and flooding; Cd bioconcentration factors (BCFs) of R. amphibia reached the maximum of 3.8870 in 75% and R. sylvestris reached the maximum of 3.2330 in 95%; sufficient water resulted in the decrease of photosynthetic rate due to more Cd accumulation. However, under flooding condition, because of the decrease of Cd bioavailability in soil, the accumulation of Cd in shoots declined and the net photosynthetic rate (Pn) enhanced slightly.

The phenotypic and genetic effects of drought-induced stress on apical growth, ring width, wood density and biomass in white spruce seedlings

Forest plantations play an important role in maintaining a supply of high-quality timber from managed forest. With an expected increase in the prevalence of drought in some forested areas, climate change increases concerns about future seedling growth. A promising approach to promote the suitability of plantation seedlings to current and future climate would be to use variation in growth and wood traits of trees under drought as selection criteria in tree breeding programs, especially at a young stage when they are most vulnerable to drought. We evaluated the genetic control of the growth and wood density response of white spruce clonal seedlings submitted to various drought conditions in a greenhouse experiment. By varying the watering treatment of 600 two year-old seedlings from 25 clones, we simulated three levels of drought-induced stress during two growing seasons. Apical and radial growth decreased markedly as the intensity of drought increased, whereas wood density tended to increase. We also developed a woody biomass index composed of wood density and ring area, which was observed to decrease slightly with increasing drought. There was important variation in all traits among clones and heritability tended to decrease with the intensity and duration of drought-induced stress, mainly for wood density and radial growth. However, the heritability of apical growth tended to increase under drought conditions. Our results show that the response of young white spruce clones to drought is highly variable, and together with the significant levels of heritability noted, the results indicate that multi-trait genetic selection for drought stress response at a young age could represent a promising approach to increase resilience to drought.

Production of clonal seedlings of black pepper cv. Bragantina under doses of controlled-release fertilizer

Commercial substrates and their fertilization are essential for the morphophysiological, nutritional, and sanitary quality of seedlings. In this perspective, this study aimed to evaluate the quality of clonal seedlings of the black pepper cultivar Bragantina under doses of controlled-release fertilizers (CLF) in a commercial substrate. The treatments were constituted by five doses of the CLF Osmocote® 19-06-10 Mini Prill (3-4 months) (0, 2, 4, 6, and 8 kg m-3), with four replications of 16 cuttings. The CLF Osmocote®, especially in doses close to 4.16 kg m-3, showed to be promising for the production of clonal seedlings of the black pepper cultivar Bragantina.

Comparative Morphological, Anatomical and Physiological Analyses Explain the Difference of Wounding-Induced Agarwood Formation between Ordinary Agarwood Nongrafted Plants and Five Grafted Qi-Nan Clones (Aquilaria sinensis)

Agarwood is the dark resinous heartwood of injured ordinary Aquilaria sinensis (OA). Recently, some new clones of A. sinensis (Qi-Nan) that intensively produce high-quality agarwood were selected and cultivated by grafted clonal seedlings. However, very little is known about their agarwood formation mechanism, and it is unclear whether the current method of distinguishing Qi-Nan from OA by observing its leaf apparent morphology is scientifically reliable. In this study, the differences between OA and Qi-Nan clones in agarwood formation and their correlation with morphological, anatomical and physiological characteristics were investigated in two types of A. sinensis trees. After the mechanical injury, agarwood yield and essential oil content in agarwood of Qi-Nan were significantly higher than that of OA. There was no significant difference in leaf shape parameters between Qi-Nan and OA, but Qi-Nan showed higher specific leaf weight, total leaf chlorophyll, leaf nitrogen content and net photosynthetic rate. A xylem anatomical analysis showed that Qi-Nan had significantly smaller vessel wall thickness, greater ray cell wall thickness and larger interxylary phloem area than OA. Moreover, Qi-Nan had a greater consumption of non-structural carbohydrates than OA. Agarwood yield and oil content in agarwood showed significantly positive correlations with leaf photosynthetic capacity, the wall thickness of xylem ray cell, interxylary phloem area, starch utilization rate of trees, and a significantly negative correlation with the wall thickness of xylem vessel of trees. In brief, Qi-Nan has a stronger photosynthetic basis to supply more carbon sources, a more efficient xylem structural basis for agarwood production and a higher carbon source utilization rate, leading to a higher agarwood yield and oil content. It is not reliable to distinguish Qi-Nan from OA simply by observing leaf apparent morphology.

RESPONS PERTUMBUHAN BIBIT KARET (Hevea brasiliensis Muell.Arg) KLON PB 260 SATU PAYUNG TERHADAP PEMBERIAN PUPUK KOMPOS BATANG PISANG

The use of polybags and topsoil planting media often causes the development of seedlings is not maximal because the topsoil is too dense. As well as continuous inorganic fertilization is not balanced with the provision of organic fertilizers cause the planting media to become dense. One of the efforts in overcoming this is by providing compost. Compost can improve soil fertility and can improve soil structure. This research was conducted with the aim to find out how the influence of banana stem compost fertilizer on the growth of rubber seedlings (Hevea brasiliensis Muell.Arg.) Clone PB 260 one umbrella. The design used in this research is Randomized Block Design (RAK) with one factor, namely banana stem compost with 5 levels that is without composting banana stems (k0), 250 g / polybag (k1), 500 g / polybag (k2), 750 g / polybag (k3) and 1000 g / polybag (k4) with 5 group. The observed variables are the increase in the length of grafting buds (cm), the increase in the number of leaf strands (strands), the increase in the diameter of the graft buds (mm), the time of the appearance of the second umbrella bud (day), the dry weight of the header (g) and the dry weight of the roots (g) of rubber seedlings. The results showed that the influence of the treatment of banana stem compost fertilizer does not differ noticeable to the growth of rubber seedling clones PB 260 one umbrella on all parameters observations.

In vitro multiplication of woody bamboo in the Southwestern Amazon, Acre State, Brazil

Bamboos from the genus Guadua in the Southwestern Amazon basin are difficult to propagate because of their recalcitrant characteristics. This study aimed to evaluate the action of 6-benzylaminopurine (BA) during in vitro multiplication of G. latifolia in a laboratory for clonal seedling production. In vitro multiplication was performed using the cytokinin 6-benzylaminopurine at concentrations of 0, 2, 4, 6, 8 mg L-1 in glass tubes containing liquid medium, incubated for 38 days. The analyzed variables were shoot height, number of shoots, multiplication rate, and the presence of callus and roots in two consecutive subcultures. The use of 6-benzylaminopurine during in vitro multiplication was effective at increasing the number of shoots in the first and second subculture. Shoot height was not influenced by the cytokinin in the culture with a maximum multiplication rate of 4.44 shoots. Therefore, the use of 6 mg L-1 of BA is recommended during in vitro multiplication and to obtain a high multipication rate.

Technical feasibility of minicutting of different portions of the branch to produce clonal seedlings of Aloysia citrodora

Seedling production using the minicutting technique enables quick and efficient plants formation. However, there are no reports of application for Aloysia citrodora (lemon verbena) and the ideal portion of the branch. This study aimed to evaluate the production of seedlings from minicuttings taken from different parts of the branch.The experiment was performed in a completely randomized design. Three treatments consisted of minicuttings taken from other branch portions (basal, median, and apical), divided into two experiments (Exp1 and Exp2).Exp1 was carried out in a sub-irrigation system in phenolic foam, evaluating rooting percentage, length of the longest root, root number, number of shoots, number of leaves, and total dry mass. Exp2 used the minicuttings from the previous experiment, kept for another 35 days in pots to assess the quality of the seedlings, evaluating plant length, number of shoots, and leaves. For Exp1, 35 days after cutting, there was a higher percentage of survival, size of the longest root, number of the root, number of shoots, number of leaves, and total dry mass, in those minicuttings produced from the basal and median portions, being the exact behavior of Exp2, 35 days after transplantation to pots. The minicutting proved to be an efficient method for producing Aloysia citrodoraseedlings, when removed from the basal or median portion, standing out for a higher percentage of survival, better growth, and initial development and post-transplantation of the produced seedlings.

Annual Fluctuation of Stress Wave Velocity and Young's Modulus of Standing Trees from 2 to 10 Years after Planting Clone Seedlings of Japanese Cedar (<i>Cryptomeria japonica</i>)

Annual Fluctuation of Stress Wave Velocity and Young's Modulus of Standing Trees from 2 to 10 Years after Planting Clone Seedlings of Japanese Cedar (<i>Cryptomeria japonica</i>)

Analysis of Cocoa Clonal Seedlings Purity Through Deoxyribonucleic Acid (DNA) Barcoding and Random Amplification of Polymorphic DNA (RAPD) Fingerprinting

The genetic purity of a plant indicates the similarity properties between seedlings in the field and the description of the plant in the database. Identifying plant purity through a morphological approach has several drawbacks, including time efficiency and environmental factors, and the diversity is limited and inconsistent. This condition encourages the development of detection methods using DNA molecular markers. Plant identification through fingerprinting or the use of molecular markers has not been widely carried out on a commercial scale, considering the investment costs for this analysis are still quite expensive. Another method used for plant identification through DNA Barcoding by comparing variations between DNA sequences. The primers used to identify barcodes on cocoa were derived from the chloroplast genome, including rbcL and matK. This research aims to see the consistency of the rbcL primer when applied to other cocoa clones, and the analysis of the polymorphic diversity of each cocoa clone using DNA fingerprinting RAPD. This method will be tested on clones of Sulawesi 1, Sulawesi 2, ICCRI 03, and ICCRI 09, which were propagated by SE and mother plants in the field using cocoa leaf samples. The stages include DNA extraction, sequencing, and analysis of the sequencing results. The results of seedlings uniformity analysis using DNA barcoding on cocoa plants produced from in vitro propagation showed that the multiplied seeds did not show any difference in sequence with the parent plant (DR2, Sulawesi 1, Sulawesi 2, and ICCRI 09). The analysis of the diversity of cocoa clones DR 2, MCC 2, Sulawesi 1, Sulawesi 2, and ICCRI 09 through DNA Fingerprinting RAPD showed that the OPA 15 primer produced a more apparent polymorphic band than the other three primers (OPP 08, OPW 11, and M 29).

Hormetics effects of glyphosate on coffee plants – guidelines for coffee

Glyphosate stands out among non-selective herbicides used for management of weeds in coffee crops due to its favorable physical-chemical, economical, and environmental characteristics. The hormetic effect is the tonic effect of low doses of toxic substances, such as herbicides, on plants. The present study was conducted at the IFSULDEMINAS, Muzambinho campus, Minas Gerais, Brazil, to identify the hormetic effect of glyphosate on coffee seedlings (Coffea arabica cv. Catuaí Vermelho 144), using different low doses of the herbicide. The experiment was conducted in a randomized block design. The treatments consisted of 8 glyphosate herbicide low doses (0, 22.5, 45, 90, 180, 360, 720, and 1,440 g ha-1) distributed in three blocks, containing ten plants per plot, using a two-plant border between treatments, totaling 240 plants. The plant development over time was simulated using non-linear models. Growth models were adjusted using the Lorentz model to analyze the regression with four parameters. Stem diameter, plant height, and total leaf areawere evaluated from 7 to 63 days after the herbicide application. Hormetic effect on the coffee seedlings evaluated was found when using the low doses of 22.5 g ha-1 and 45 g ha-1, and the best effect was found with the low dose of 22.5 g ha-1. Low doses of 300 g ha-1 glyphosate stimulated the sprouting of coffee plants, and this dose is interesting for clonal seedlings. Key words: Chemical control; Coffea spp.; herbicide; phytotoxicity; low doses.