In vitro Propagation of Banana (Musa paradisiaca L.) Plant Using Shoot Tip Explant

Banana is a fruit crop which has high demand in Ethiopia, but its production is constrained by lack of disease free planting material with conventional propagation methods. For shoot initiation, shoot tip explants were cultured on MS medium supplemented with 0.5, 1.0, 1.5 and 2.0 mg/L BAP. Similarly, MS medium supplemented with BAP at 1.0, 1.5, 2.0 mg/L in combination with IBA at 0.25 and 0.50 mg/L were used for shoot multiplication. Half- strength MS medium augmented with IBA at 1.0, 2.0, 3.0 and 4.0 mg/l were used for root induction. MS medium without PGRs were used as controls. Finally, hardening of the in vitro derived plantlets was carried out in green house both in the primary and secondary acclimatization stages. Results showed that the highest shoot initiation percent (93.40%), highest mean number of shoots per explant (4.67) and lesser day for shoot induction (11.00) were observed in explant cultured on MS + 1.0 mg/L BAP. With shoot multiplication, highest shooting percent (92.60%), maximum number of shoots (7.67) and highest shoot length (5.27 cm) were recorded on MS + 1.5 mg/L BAP + 0.5 mg/L IBA. The highest rooting percent (93.40%), maximum root number per shoot (7.67) and highest root length (11.00 cm) were found on a half strength MS medium + 2.0 mg/L IBA. The survival rate of plantlets were 96.00% in coco peat substrate in primary acclimatization and 97.92% in forest soil, sand and manure substrates mixed at 3:2:1 ratio in secondary acclimatization. Overall, the result showed that the PGRs type, concentrations and combinations used are effective for mass propagation of banana variety studied in this experiment.

Micropropagation of Cassava (Manihot esculenta Crantz): Review

Cassava is a vital crop to the food security of millions of people worldwide, particularly in Sub-Saharan Africa. Because the crop produced a reasonable yield on marginal soils, it could help relieve global hunger. As a result, increasing cassava output and its quality attributes are significant. However, the low multiplication rate of this main crop has resulted in the delayed dissemination of improved varieties among farmers. As a result, tissue culture techniques may be a feasible solution for overcoming these challenges. Cassava in vitro propagation had done using either the shoots multiplication technique or somatic embryogenesis. However, the shoot multiplication approach is preferable since it retains clonal fidelity. Plant regeneration via somatic embryogenesis or organogenesis entailed the use of numerous basal media containing various plant growth hormones. Several studies found that each type of cassava clone required a unique protocol to achieve optimal shoot initiation, shoot multiplication, root induction, and elongation. This review describes recent research on cassava micropropagation that makes use of a variety of experimental systems. While each of these systems focuses on a different aspect of technique, they can be significant in understanding the in vitro production of cassava planting material.

Endophytic Bacteria in Banana In Vitro Cultures: Molecular Identification, Antibiotic Susceptibility, and Plant Survival

Microbial contamination is a common problem that causes significant losses in plant micropropagation systems. The present study reports on the identification and control of bacterial contaminants in banana in vitro cultures. Twelve isolates belonging to Bacillus pumilus (S2), Bacillus subtilis (R2 and M4), Geobacillus stearothermophilus (S1, S3, S4, P2, M3 and R3) and Paenibacillus spp. (P1, R1 and M2) were identified by sequencing of 16S rRNA, gyrA or gyrB genes. Antibiotic susceptibility testing was performed with the disk diffusion method on bacterial isolates using 36 antimicrobial agents. Some antibiotics, notably Ticarcillin, Penicillin, Ampicillin, Cefazolin and Imipenem, had a broader range of bactericidal activity than others did. When contaminated axillary shoot cultures of banana were treated with 100 or 200 mg·L−1 of ticarcillin, ampicillin or penicillin the bacteria were eliminated, but a reduction in shoot multiplication and growth was observed. These findings contribute to minimizing the losses in the commercial micropropagation of banana.

Protocol Optimization for Rapid Multiplication of Cassava (Manihot esculenta Crantz) using the Nodal Segment

Background: Cassava is a vital food security crop for millions of people, especially in sub-Saharan Africa. Since the crop produces a reasonable yield on marginal soils, it could help alleviate world hunger. Consequently, the increase in cassava production and its quality characteristics are significant. However, the low multiplication rate of this main crop has delayed the spread of improved varieties among farmers. As a result, tissue culture techniques can be a viable solution to overcome these challenges. Methods: The study used a nodal segment as an explant to evaluate different concentrations of BAP and NAA for an efficient, cost-effective in vitro mass multiplication of the AWC-1 cassava variety. CuSO4, commercial bleach and ethanol had used to sterilize nodal explants taken from greenhouse-grown plants at various time intervals. Result: The best medium for micro shoots induction had found to be medium without growth regulators. Among different treatments used for shoot multiplication purposes, the maximum shoot number has been recorded on M.S. medium supplemented with 0.75 mg/l BAP and 0.2 mg/l NAA. Medium with 0.5 mg/l NAA concentration was the best for rooting induction. A survival rate of 86% has obtained in the greenhouse and the plantlets appeared to be morphologically normal.

In vitro shoot multiplication of Morus nigra by combinations of plant growth regulators

Mulberry (Morus nigra L) is a dicotyledonous plant in the family Moraceae which often used for silkworms’ breeding. Mulberry propagation still uses conventional technology, such as cuttings and graftings. The problem of mulberry propagation is the low productivity of mulberry gardens. However, tissue culture is a technique of isolating plant parts in the form of organs, cell tissues, and protoplasms that is effective and efficient in order to get uniform and superior plants in a short amount of time. For mulberry growth, the right combination of the Plant Growth Regulator (PGR) in the form of Kinetin, IAA, IBA is needed. Data were analyzed using R-statistic software. The results showed that M6 media (MS + Kinetin 1.5 + 1 IAA) was the best combination of media for the number of shoots, leaf length, and number of roots, with 80% of live explant percentage. Propagation via tissue culture such as clonal propagation, organogenesis, and somatic embryogenesis in callus cultures followed by generation of shoots/plantlets represents a potential effective propagation method in the future.

Inisiasi, pertumbuhan, dan perkembangan kalus embriogenik tanaman stevia (Stevia rebaudiana)

The leaves of sweetener plant Stevia rebaudiana contain secondary metabolites of steviol glycosides which are very sweet, with no calorie and zero glycemic index. Propagation of stevia by seeds is ineffective due to its low germination rate and diverse progenies. The tissue culture of stevia can be used to mass propagate rapidly and is commonly conducted by shoot multiplication. Up to now, the technology of somatic embryogenesis (SE) in stevia has not been successful yet. SE is developed to increase the production scale, rejuvenate clonal-propagated plants, and plant genetic transformation. The research objective was to develop protocols for the initiation, proliferation, and development of embryogenic calli of stevia as potential materials for SE. The explants used were young leaves, nodes, and internodes of axenic plantlets of stevia BX clone. The explants were cultured on MS solid media containing different concentrations of auxin and cytokinin for callus initiation. Callus emerged after 2-3 weeks of culture. The calli obtained were proliferated by subculturing several times as material stocks for indirect SE. MS solid media added with 1 µM 3,4-D and 16 mM CaCl2 gave the highest callus multiplication rate (4.7 times in 3 weeks). The selection of embryogenic calli was made continuously to obtain a pure line of embryogenic calli. Three types of calli attained were friable, fast-growing, yellowish calli, shiny nodular calli, and greenish nodular calli. Histological studies revealed that cells of the nodular calli had been differentiated to potentially formed somatic embryos.

Alteration of Flower Color in Viola cornuta cv. “Lutea Splendens” through Metabolic Engineering of Capsanthin/Capsorubin Synthesis

Flower color is an important characteristic that determines the commercial value of ornamental plants. The development of modern biotechnology methods such as genetic engineering enables the creation of new flower colors that cannot be achieved with classical methods of hybridization or mutational breeding. This is the first report on the successful Agrobacterium-mediated genetic transformation of Viola cornuta L. The hypocotyl explants of cv. “Lutea Splendens” variety with yellow flowers were transformed with A. tumefaciens carrying empty pWBVec10a vector (Llccs−) or pWBVec10a/CaMV 35S::Llccs::TNos vector (Llccs+) for capsanthin/capsorubin synthase gene (Llccs) from tiger lily (Lilium lancifolium). A comparative study of shoot multiplication, rooting ability during culture in vitro, as well as phenotypic characteristics of untransformed (control) and transgenic Llccs− and Llccs+ plants during ex vitro growth and flowering is presented. Successful integration of Llccs transgene allows the synthesis of red pigment capsanthin in petal cells that gives flowers different shades of an orange/reddish color. We demonstrate that the ectopic expression of Llccs gene in ornamental plants, such as V. cornuta “Lutea Splendens” could successfully be used to change flower color from yellow to different shades of orange.