Highest Multiplication Rate Research Articles

Pre-Germinative Treatments and In Vitro Germination of Dianthus caryophyllus and Alstroemeria spp. Seeds

Alstroemeria spp. and carnation (Dianthus caryophyllus L.) have considerable and increasing economic importance in the floriculture market, therefore breeders carry out intense breeding programs to select new superior varieties. However, poor germination of hybrid seeds remains a bottleneck. Based on this assumption, seed pre-treatments and in vitro germination protocols, using different germination substrates, were applied in Alstroemeria spp. and carnation to improve germinability. Seed viability was tested using the 2,3,5-triphenyl tetrazolium chloride (TTC) test, and resulted in 91.10% ± 2.33 and 86.66% ± 3.85 in Alstroemeria and carnation, respectively. In Alstroemeria, pre-treatment with potassium nitrate (KNO3) in combination with modified ½ Murashige and Skoog (MS) medium ensured high germination uniformity combined with high germination percentage, showing significantly higher values than the control. In carnation, a suitable seed sterilization procedure was set up (up to 95.8% sterility); treatments with gibberellic acid (GA3) and KNO3 did not influence germination percentage compared to the control. A high multiplication rate of seedling lines was obtained on hormone-free MS medium.

NRBP1 promotes malignant phenotypes of glioblastoma by regulating PI3K/Akt activation.

Glioblastoma (GBM) is the most aggressive of intracranial gliomas. Despite the maximal treatment intervention, the median survival rate is still about 14-16 months. Nuclear receptor-binding protein 1 (NRBP1) has a potential growth-promoting role on biology function of cells. In this study, we investigated whether NRBP1 promotes GBM malignant phenotypes and the potential mechanisms. The correlation between NRBP1 and glioma grade, prognosis in TCGA/CGGA databases and our clinical data were analyzed. Next, we conducted knockout and overexpression of NRBP1 on GBM cells to verify that NRBP1 promoted cell proliferation, invasion, and migration invitro and invivo. Finally, we detected the impact of NRBP1 on PI3K/Akt signaling pathway and EMT. There was a correlation between elevated NRBP1 expression and advanced stage glioma, as well as decreased overall and disease-free survival. The suppression of proliferation, invasion, and migration of tumor cells was observed upon NRBP1 knockout, and invitro studies also demonstrated the induction of apoptotic cell death. Whereas, its overexpression is associated with high multiplication rate, migration, invasion, and apoptotic escape. GO enrichment and KEGG analysis revealed that NRBP1 regulated differentially expressed gene clusters are involved in PI3K/Akt signaling pathway, as well as EMT mediated by this pathway. Moreover, the effects of NRBP1 knockdown and overexpression on GBM were mitigated by MK-2206 and SC79, both of which respectively function as an inhibitor and an activator of the PI3K/Akt signaling pathway. Similarly, the suppression of NRBP1 led to a decrease in tumor growth, whereas its overexpression promoted tumor growth in a mouse model. This study shows that NRBP1 promotes malignant phenotypes in GBM by activating PI3K/Akt pathway. Hence, it can function as both a predictive indicator and a new target for therapies in GBM treatment.

Razmnožavanje biljke miskantus postupkom mikropropagacije

Miscanthus is a perennial grass native to East Asia. Although miscanthus primarily spread in Europe and North America for its use as an ornamental grass, growing this plant is financially demanding, resulting in a limited area of cultivation in Europe. The aim of this work is to describe in detail different micropropagation systems applied to the miscanthus plant. Miscanthus propagation is done vegetatively, using underground rhizomes or young plants grown by tissue culture, known as micropropagation. Micropropagation stands out as an alternative and extremely efficient method of reproduction, given the high rate of multiplication and the additional advantage of preventing disease transmission. It represents a method of vegetative reproduction that takes place on artificially created nutrient media, controlled growth conditions and in vitro sterile conditions. Research materials and methods were based on latent buds of three-year Miscanthus × giganteus rhizomes. A 70 percent ethanol solution and a 0.1 percent HgCl2 solution were used for sterilization. Micropropagation of the miscanthus plant is an important technique for breeding purposes in the future as it offers a diverse range of advantages compared to the limitations of common and natural reproductive barriers in conventional breeding techniques. The results of this research are based on the fact that the process ensures a quick process of obtaining a large number of plants that are identical in genetic potential, growth and development of the species. This paper is structured in such a way as to point out the importance of miscanthus production by micropropagation, its characteristics, current knowledge about this plant, the achievements, future and perspective of miscanthus micropropagation using the in vitro technique.

The effect of sodium nitroprusside on the vegetative development of Aronia melanocarpa [Michx.] Elliot under in vitro conditions

Aronia is a berry fruit that has a significant amount of antioxidants. Both sexual and vegetative methods of propagation are available for aronia. Genetic diversity is present in the process of seed propagation. Therefore, clonal propagation techniques such as cuttings, basal shoots, and tissue culture are preferred. Plant tissue culture is a process that offers a high multiplication rate and the ability to produce clean plant material. This study aimed to stimulate the growth of plantlets by introducing several growth-promoting agents into the culture media. Specifically, the effects of a nitric oxide donor SNP (sodium nitroprusside) on the vegetative development of the plants were examined under in vitro conditions. Four distinct concentrations of SNP (0, 100, 200, and 300 µM) were administered to promote vegetative development. The survival rate (%), rooting rate (%), root number (per plantlet), root length (cm), leaf number (per plantlet), shoot length (cm), plant fresh weight (g), and plant dry weight (g) of the plantlets were estimated on the 60th day of growth in the nutrient medium under in vitro conditions. The survival rate was 100% for the applications of SNP at concentrations of 100 µM and 200 µM. The 0 µM treatment had the highest root number, the 100 µM treatment had the longest root, and the 200 µM treatment had the highest values for shoot length. The 0 µM treatment provided the highest values for plant fresh weight, while the 0 and 100 µM applications resulted in the highest plant dry weight values. The study suggested that an increased concentration of SNP causes a toxic effect.

Plant Growth-Promoting Bacteria Enhance Survival, Growth, and Nutritional Content of Sugarcane Propagated through Pre-Sprouted Seedlings under Water Deficit

Sugarcane plays a crucial role in global sugar and ethanol production. Conventionally, sugarcane propagation involves planting billets. However, Brazilian researchers have introduced the innovative pre-sprouted seedlings (PSS) method, widely used in the MEIOSI (Simultaneously Occurring Interrotational Method) system. Although PSS has several advantages over the conventional method, its sensitivity to water scarcity is a challenge. This study aimed to evaluate the survival and growth of PSS inoculated with Bacillus licheniformis and Bacillus subtilis (PGPB) under different water regimes. The experiment was conducted in the field in a randomized block in strips (split-block) using a 2 × 4 factorial scheme consisting of two inoculation conditions (with and without PGPB) and four water regimes (WR) (0%, 33%, 66%, and 100% of the ideal irrigation). PGPB increased PSS survival (4.17%) and water use efficiency (185.10% under the 0% WR). In addition, inoculation increased root (12.5%, 7.7%, and 16.2% for surface area, area projection, and root volume, respectively) and shoot growth. PGPB also increased nutrient uptake, such as N (60.8% and 18.3% under 0% and 66% WR), P (on average 11.7%), Mn (27.6% and 28.7% under 66% and 100% WR), Zn (111.4% under 0% WR), and Cu accumulation (27.17%), which provided a higher number of stalks per meter and, therefore, a higher multiplication rate in the MEIOSI system. Inoculation proved to be a promising alternative for PSS establishing under water restriction.

Efeito combinado de citocininas na propagação in vitro de três cultivares de morango

ABSTRACT In the in vitro propagation of strawberry plants, techniques have been applied to obtain disease-free plants with high multiplication rates. To improve the efficacy of micropropagation protocols, it is necessary to determine the effect of growth regulators, mainly cytokinins; however, there is no information regarding the combined use of trans zeatin (Zt) and other cytokinins for shoot induction. The objective of this work was to evaluate the effect of Zt combined with 6-benzylaminopurine (BAP), 6-furfurylaminopurine (KIN) or 2-isopentenyladenine (2iP) on the in vitro propagation of three strawberry cultivars. Combinations of cytokinins, Zt and BAP, Zt and KIN, and Zt and 2iP were proposed to evaluate shoot induction. For the acclimatization of the seedlings, two types of substrates were used (Pro-Mix, Pro-Mix plus humus 2:1). The use of Zt and KIN increased the average number of shoots per explant, and the greatest number of leaves and roots was obtained when Zt and 2iP or Zt and BAP were used. The Pro-Mix and Pro-Mix plus humus substrates did not significantly affect the number of leaves or roots, or the SPAD. These results indicate that the use of the combination of Zt and KIN allowed us to obtain the greatest number of shoots per explant that did not produce calli and promoted the development of the root system; likewise, the Pro-Mix or Pro-Mix plus humus substrate were adequate for acclimatization, allowing the growth and development of strawberry plants.

Effect of different cytokinin sources on in vitro/ex vitro multiplication and rooting rate in Eucalyptus spp.

Eucalyptus globulus Labill. is of great interest to the pulp industry. However, the species is highly susceptible to leaf spot caused by Teratosphaeria nubilosa and has a low rooting capacity. In order to overcome these limitations, INIA has been implementing a genetic improvement program for this species and the generation of interspecific hybrids. The strategy is based on the selection of E. globulus clones with high precocity or foliage turnover, since the adult foliage is more tolerant to T. nubilosa. In addition, controlled crosses of E. globulus and E. maidenii with E. grandis are carried out to incorporate disease resistance and ease of rooting. The multiplication of the selected materials is carried out by micropropagation, but the low rooting capacity is a trait that needs improvement. The cytokines necessary for in vitro proliferation can have a negative effect on the rooting process. Benzyladenine is the most commonly used cytokine because of its low cost and easy availability, with some negative effects on rooting, while meta-topolin is a cytokine of lesser impact. The objective of this study was to evaluate the effect of benzyladenine and meta-topolin on the multiplication rate, rooting percentage and plantlets survival of E. globulus, E. grandis × E. globulus, and E. grandis × E. maidenii. In multiplication media, benzyladenine was supplied at 0.4 µM, while two concentrations of meta-topolin (0.4 and 2 µM) were used. Preliminary results indicated a higher multiplication rate with the inclusion of meta-topolin in both concentrations. The in vitro rooting percentage of explants treated with meta-topolin was 51% and 44%, at 0.4 and 2 µM, respectively, while with benzyladenine was lesser (37%). After 28 days post-transplanting, survival was higher in meta-topolin-derived plants. Meta-topolin improved multiplication, in vitro rooting and acclimation of plants. The use of this hormone could improve micropropagation protocols, facilitating rooting and multiplication of valuable genotypes.

Establishment of In Vitro Cultures and Genetic Fidelity Analysis in Valeriana jatamansi -a High Value Endangered Medicinal Herb

The present study was conducted in the Department of Biotechnology, College of Horticulture and Forestry, Neri, Hamirpur, Himachal Pradesh, India during 2018–2020 for 18 months to develop an efficient, rapid and reproducible protocol for in vitro establishment along with analysing antioxidant activity. In the present study, surface sterilization protocol was standardized using Sodium hypochlorite and mercuric chloride as sterilant. Maximum direct shoot induction frequency from nodal explant was achieved on Murashige and Skoog medium enriched with BAP (5.0 mg l-l), TDZ (3.0 mg l-l) and NAA (1.0 mg l-l) for 18 days. Microshoots inoculated on MS media supplemented with 4.0 mg l-l BAP, 2.0 mg l-l TDZ, 1.0 mg l-l NAA and 0.5 mg l-l GA3) showed maximum frequency of shoot multiplication with average shoot length (4.36±0.08 cm) and average shoot number (14.00±0.57). A 75.00±1.15% rooting with significantly high mean root number (8.00±0.57) and root length was achieved in full strength MS medium, supplemented with same concentration i.e. 4.0 mg l-l BAP, 2.0 mg l-l TDZ, 1.0 mg l-l NAA and 0.5 mg l-l GA3) combination. Maximum plantlets survive after 1 year of acclimatization. RAPD and ISSR markers were used to confirmed genetic stability of in vitro raised plants by showing 100% monomorphism. High multiplication rate associated with genetic stability ensure the efficacy of the present in vitro clonal propagation protocol of this important medicinal plant.

Establishment of An in Vitro Mass Propagation System for Dendrocalamus asper.

Dendrocalamus asper is a species of bamboo that has high commercial value and is the bamboo of choice for large scale agro-forestry plantations in the tropical regions of the world. Micropropagation using tissue culture is essential to generate uniform clones that are amenable to establishment in industrial agro-forestry projects for bamboo biomass, habitat restoration or in carbon sequestration. This paper reports on the establishment of D. asper invitro using commercially available seeds. The seeds were surface sterilized using three different chemical agents which were Sodium Hypochlorite (20%), Mercuric Chloride (0.1%) and Ethanol (70%) followed by shoot initiation on Murashige and Skoog (MS) medium supplemented with 6-Benzylaminopurine (BAP) with a concentration ranging from 1.0 - 5.0 mg/L. Propagules were multiplied on MS media supplemented with different concentration of IBA Indole-3-Butyric Acid (IBA) and Naphthalene Acetic Acid (NAA), and finally rooted and hardened in peat moss. The findings of our study indicate that the sterilization protocol eliminated all the plant pathogens, resulting in an axenic culture. Full strength MS medium supplemented with 5 mg/L BAP yielded the highest number of shoots (11.46 per explant) after four weeks of inoculation. The highest multiplication rate (3.95 shoots per explant) was obtained on MS medium supplemented with 3 mg/L BAP. The time required from initiation to hardening was 70 to 90 days, following which the plantlets were ready for field trials. The findings of this study will facilitate the establishment of plant tissue culture programmes dedicated to the production of D. asper locally, thus eliminating the need for imports and the possible entry of plant pathogens that can be detrimental to the local agro-forestry industry.

Prevalence of Aminoglycoside Resistance Genes in Clinical Isolates of Pseudomonas aeruginosa from Taif, Saudi Arabia-An Emergence Indicative Study.

Hospital-acquired infections caused by P. aeruginosa contribute to global distress because of the elevated rates of microbial antibiotic resistance. Aminoglycosides are antipseudomonal agents that are effectively and frequently utilized to eradicate this infection. This current study is a retrospective study investigating plasmid-mediated aminoglycoside resistance by focusing on the prevalence of the genes encoding aminoglycoside-modifying enzymes (AMEs) and 16S rRNA methylase among P. aeruginosa clinical isolates from Taif, Saudi Arabia. A hundred clinical isolates of P. aeruginosa were collected. The isolates were identified from February 2021 to February 2022. Antibiotic susceptibility testing and MICs were determined using (DD) and (BM-MIC) testing, respectively. AMEs and 16S rRNA methylase variants in bacterial isolates were amplified via PCR for genetic detection. A relatively high multiple antibiotic resistance rate corresponding to 10-32% was reported. Eighteen percent of P. aeruginosa isolates were gentamicin-amikacin-tobramycin resistant according to the MIC levels. The aminoglycoside-resistant strains were additionally identified via GyrA gene sequencing. The phylogenic relatedness dendrogram of the sequenced GyrA genes was performed using a neighbor-joining method via MEGAX software version 10.2.6. The most prevalent AME encoding gene was aac(6')-Ib, observed in 94.4% of resistant isolates, while a resistance gene cocktail of [aac(6')-Ib and ant(3″)-I] was a highly frequent combination (27.8%). This study updated the knowledge about aminoglycoside resistance mechanisms in P. aeruginosa, which constitutes an urgent need, especially after the COVID-19 crisis, which was associated with increased antimicrobial use and resistance rates.

IN VITRO MORPHOGENESIS OF GYPSOPHILA: RESPONSE TO EXOGENOUS PHYTOHORMONES

The success of in vitro cultivation of plant species depends on factors associated with the induction and control of morphogenesis regarding the regeneration of shoots and roots in the organogenesis process, such as the culture medium composition. Thus, the objective of this study was to investigate if the concentration of growth regulators in culture medium interferes with the in vitro morphogenesis of gypsophila. ‘Golan’ cultivar was subjected to three culture media (M), which constituted the study treatments: M1) Murashige and Skoog (MS) medium without the addition of growth regulators; M2) MS + 1 mg L-1 of benzylaminopurine (BAP) + 0.05 mg L-1 of naphthaleneacetic acid (NAA); M3) MS + 0.05 mg L-1 BAP + 1 mg L-1 NAA. After 45 days, the multiplication rate, plant height and root length were evaluated. The results showed that plantlets produced in M2 medium had a higher multiplication rate. Also, plantlets produced in M1 and M3 media showed higher shoot height and root length. It is concluded that there is a difference in the in vitro morphogenesis of gypsophila according to the concentration of growth regulators in the micropropagation medium.

Energy Efficiency of LEDs during Micropropagation of Helleborus ‘Molly’s White’

For many years, there has been a growing trend toward producing plants using tissue culture, the most efficient method at present. Every year, more and more protocols for micropropagation of economically valuable species are appearing. Many factors influence the regenerating explants under sterile laboratory conditions. One of the most important is light. The aim of the present study was to increase the efficiency of micropropagation of hellebore ‘Molly’s White’ using energy-efficient light-emitting diodes (LEDs), which were compared to traditionally used fluorescent lamps (FLs). To choose the best light and reduce production costs, white, blue or red LEDs with two levels of photosynthetic photon flux density (PPFD), 40 and 70 μmol/m2/s, were used at the multiplication and rooting stages. LED light color has been shown to affect regeneration rate and plant growth in length during micropropagation, while both light parameters (color as well as intensity) affect the length of regenerating shoots and the content of assimilation pigments in plants. The use of white LED light, which gives the highest multiplication rate, at an intensity of 70 μmol/m2/s saves more than 57 kWh during an 8-week micropropagation cycle compared to conventional fluorescent lamps with the same parameters.

Liquid Culture System: An Efficient Approach for Sustainable Micropropagation

Micropropagation of important forestry, horticultural and medicinal plants have made revolutionary changes in terms of research and commercialization. However, there are a variety of factors which influence the scaling-up and commercialization aspects, which decide whether mass propagation will be effective and lucrative. Low rates of shoot multiplication, increased costs of media components, loss of cultures due to contamination, and difficulties with hardening and acclimation are the key obstacles to scaling up micropropagation technology. These restrictions have forced a large number of in vitro technologies developed for a range of plant species to be used only under research laboratories settings. To apply tissue culture technology to large-scale propagation, it is required to develop techniques that are relatively simple to adopt, have high multiplication rate with high levels of reproducibility, and exhibit higher survival of plantlets when transferred to ex vitro conditions. Efficient techniques include utilization of liquid culture systems and replacement of agar with other gelling agents. These techniques allow development of micropropagules that not only function better in post-vitro soil conditions and are comparatively less expensive, but will also help develop a workable micropropagation technique that can be applied to the mass production of desirable plant species. The current review describes liquid culture system as an efficient approach to produce large number of plants at low production cost.

Role of Phytohormones in Biomass and Polyphenol Accumulation in Salvia bulleyana In Vitro Culture.

Salvia bulleyana is a plant native to the Chinese Yunnan Province. This species has been used in traditional Chinese medicine as a substitute for Danshen (the roots of Salvia miltiorrhiza). The aim of our study was to establish an effective system for propagating S. bulleyana shoots to obtain large amounts of material rich in bioactive compounds. Phytohormones were used to regulate shoot growth and regeneration potential and influence plant secondary metabolism. The shoot tips were incubated on a Murashige and Skoog agar medium supplemented with 0.1 or 0.5 mg/L IAA (indole-3-acetic acid) and the cytokinins benzylaminopurine (BAP), meta-topoline (M-T), 6-benzylaminopurine riboside (RBAP), N-benzyl-9-(2-tetrahydropyranyl)-adenine (BPA) or kinetin, (K) at concentrations of 0.5, 1 or 2 mg/L. It was observed that the type and concentration of growth regulator significantly influenced the regeneration potential of S. bulleyana shoots. The highest multiplication rate was obtained when 0.1 mg/L IAA and 2 mg/L BPA were used. Under these conditions, 100% of shoot tips formed buds and almost seven buds/shoot per explant were obtained after five weeks. Meanwhile, the highest biomass was found for shoots growing on a medium supplemented with 0.1 mg/L IAA and 1 mg/L M-T: 1.2 g of fresh weight and 0.17 g of dry weight. However, a medium with 0.1 mg/L IAA and 2 mg/L RBAP was most favorable for bioactive phenolic acid content, with a total polyphenol level (37.7 mg/g dw) 4.5 times higher than in shoots grown on medium without growth regulators (8.23 mg/g dw). Finally, optimal conditions were selected by TOPSIS (technique for order of preference by similarity to the ideal solution); the culture of S. bulleyana grown on an MS medium containing 0.1 mg/L IAA and 1 mg/L M-T was found to be the most efficient for polyphenol accumulation and can be used for the production of medicinally relevant compounds.

Micropropagation Protocol and Genetic Stability of the Salix myrtilloides Plants Cultivated In Vitro

Salix myrtilloides L. is a relict species, threatened with extinction in many European countries. To prevent the loss of the species, tissue culture was established to produce plant material for reintroduction in natural habitats. Micropropagation was chosen as a method to obtain new plants. S. myrtilloides shoots were disinfected with NaOCl, AgNO3, or with a two-step disinfection with NaOCl, and then placed on MS medium supplemented with BA at 1 mg·dm-3 and IBA at 0.1 mg·dm-3. Regenerated shoots were cultivated in presence of BA, KIN, and 2iP to select the treatment with the highest multiplication rate. The obtained plants were acclimatized to ex vitro conditions. Inter-simple sequence repeat (ISSR) and flow cytometric analyses were conducted on in vitro regenerated plants to check their genetic stability. The best disinfection results were obtained when explants were treated with 1.5% NaOCl for 20 min. The highest multiplication rate and good quality plants were noted in the control media, without growth regualtors and in presence of kinetin at 0.5 mg·dm-3. Flow cytometry and ISSR analyses confirmed genetic stability in plantlets, which indicated the possibility to use the in vitro obtained plants for reintroduction.

FORMATION OF PRODUCTIVITY OF WINTER RAPE HYBRIDS DEPENDING ON ROW SPACING

FORMATION OF PRODUCTIVITY OF WINTER RAPE HYBRIDS DEPENDING ON ROW SPACING

Micropropagation of plants of the genus Actinidia Lindl.

Purpose. Analysis of plant micropropagation technologies for the creation of viable interspecific hybrids and varieties of Actinidia Lindl. Methods. General scientific – hypothesis, experiment, observation, analysis, synthesis method for drawing conclusions. Results. The introduction of in vitro technologies is now becoming the dominant commercial method of large-scale and rapid production of seedlings with stable inheritance of variety traits, high multiplication rate, preservation of economically valuable traits in the absence of production seasonality and time constraints. In addition to reproduction, the breeding process is also accelerated, including mutagenesis and hybridization. It is important to obtain not only a sterile explant, but also a morphogenically active one, that is, a plant that takes roots and subsequently regenerates in vitro. The best in terms of decontamination efficiency is the method of treatment with hypochlorite and the addition of PPM biocide to the nutrient medium, but under these conditions, the lowest survival of explants in all samples was noted. The efficiency of introduction into aseptic culture at the first stage of micropropagation is also affected by the biological characteristics of the primary explants. In studies with nutrient media for A. arguta, it was found that of the elements of mineral nutrition, only 11 ions are necessary for life: five macro- (N, K, P, Mg, S) and six microelements (Cl, Fe, B, Mo, Na, I). Plants in vitro have a lower dry matter content and a greater amount of moisture, including free moisture, which is quickly lost when the water balance is disturbed. Conclusions. The abi­lity to regenerate is more pronounced in the species A. chinensis and A. deliciosa, and to a lesser extent in A. arguta. For A. chinensis, the use of hydroponic technology for the adaptation of regenerants at the ex vitro stage is effective.

Trypanosoma cruzi infection induces proliferation and impairs migration of a human breast cancer cell line

Breast cancer is considered the type of cancer that most affects women in the world. The triple negative breast cancer is considered aggressive with poor prognosis. In the 1930s Russian researchers observed that T. cruzi has tropism for tumor cells. Since then, this research field has been subject of a numerous of researches. Here, we proposed to investigate the impact of T. cruzi infection on proliferation and migration of triple negative breast cancer cell line (MDA-MB-231). T. cruzi showed high invasion and multiplication rate in MDA-MB-231 cell line. The infection promoted the multiplication of MDA-MB-231 cell, continuous cell lysis throughout of days of in vitro infection and impaired MDA-MB-231 cell migration. Taken together, these results demonstrated the high susceptibility of MDA-MB-231 cell to T. cruzi and suggested that molecules from T. cruzi may impair host cell migration with potential use to avoid metastasis.

Effects on the plantain proliferation in two propagation environments brought by corm size and benzylaminopurine

Banana macropropagation in a thermal chamber is an economical technology, effective as a phytosanitary cleaning method, and efficient to enhance seedling production. The objective of this work was to evaluate the effects of corm size (CS) and benzylaminopurine (BAP) on plantain cv. Barraganete seedling proliferation in two propagation environments (PE). The treatments consisted of two levels of BAP (with and without BAP), three CS (2 ± 0.5, 4 ± 0.5 and 6 ± 0.5 kg) and two PE (thermal chamber and raised bed). The variables evaluated were sprouting time (days), multiplication rate (MT) per unit (seedlings per corm) and area (seedlings per m2). Sprouting time was significantly influenced (p < 0.05) by the PE, where the thermal chamber advanced shoot emergence by 12 days, with respect to the raised bed. MT of seedlings per corm and m2, were significantly influenced (p < 0.05) by BAP × AP and TC × AP interactions, where the highest seedling production per corm occurred inside thermal chamber with BAP and 6 ± 0.5 kg corms, while seedling production per m2 was higher with 2 ± 0.5 kg corms under the same thermal chamber conditions and with BAP. The main effects results reported that with BAP there were 30 and 31% increases in MT per corm and per m2, respectively, relative to the treatment without BAP. Within the thermal chamber the MT per corm and per m2 increased by 44% relative to the raised bed. Regarding the effect of CS, larger corms achieved higher individual MT, while smaller corms achieved higher MT per area. The use of a thermal chamber and BAP is recommended for mass production of banana seedlings through macropropagation.

Bioagents of the Chrysopidae (Neuroptera) feeding on Myzus persicae Sulzer (Hemiptera; Aphididae) in a crop of oriental tobacco

Abstract. This study was conducted with the aim to establish the bioagents of the Chrysopidae (Neuroptera) family feeding on green peach aphid Myzus persicae Sulzer (Hemiptera; Aphididae) in an oriental tobacco crop. The results showed low multiplication density of the aphidophagous species throughout the two-year course of the study. Four representatives of the Chrysopidae were established and the species with the highest densities were seven-spotted lacewing Chrysopa septempunctata Wesmael and beautiful lacewing Chrysopa formosa Brauer – 55.6% and 27.8%, respectively. Оrdinary lacewing Chrysopa carnea Stephens and green lacewing Chrysopa prasina Burmeister related to the control of the green peach aphid represented correspondingly 11.1% and 5.5% of the total number of lacewings, but single representatives were found and hence it could be assumed that they did not play a significant role in the limitation of M. persicae. Later emergence of the lacewings in the tobacco crop was observed, in the period 20th – 30th June of 2021 and 2022, which is a period of relatively high multiplication rate of the green peach aphid.