Propagation Of Seedlings Research Articles

In vitro seed germination and seedling propagation in Campanula spp

The present research investigated in vitro seed germination and seedling multiplication methods to preserve and introduce new naturalized valuable Campanula species to the floriculture markets. Populations of Campanula barbata L., Campanula latifolia L., Campanula rapunculoides L., Campanula spicata L., and Campanula trachelium L. from various sites in northern Italy were considered in this study. Seeds were sown on half-strength Murashige and Skoog (MS) basal medium with 1-naphthaleneacetic acid (NAA), 6-benzyladenine (BAP) and kinetin, added or withheld, after which final germination percentage (FGP), mean germination time and time of 50% germination (T 50) indices were measured. C. rapunculoides showed the highest FGP after 2 weeks in both the presence (53%) and absence (56%) of plant growth regulators. Among the other species, no statistical differences were detected in the presence of growth regulators, except for C. barbata, in which FGP was nearly 0%. In the absence of phytohormones, seed germination in C. spicata was statistically higher (34%), compared to C. barbata (0%), and both C. latifolia and C. trachelium (about 19%). After 4 months, the seedlings were transferred to full-strength MS basal medium with or without NAA and BAP. In all Campanula species tested, the best shoot-forming and rooting response was observed on substrates that contained plant growth regulators.

Selection intensities of families and clones in potato breeding

Families selection has not been recommended as a selection method for vegetative propagated species. To verify its utility for potato improvement a series of experiments were carried out under warm temperatures (rainy season). Thirty clonal families originated from heat tolerant parents were evaluated for tuber yield and specific gravity. After obtaining the seedling generation (SG) and the first clonal generation (FCG) individual clones from a further two generations were assessed. Simulations were conducted with different intensities of family selection in SG and FCG and intensities of clonal selection in subsequent generations. The results show that family selection intensities between 50% and 60% allowed the greatest gains. Estimates of h² at the families level were always higher than at the clones level and corroborate for the more effective selection of families in early generations. The selection of families for tuber specific gravity can be made in the early generations (SG and FCG) regardless of the temperature conditions where the individual clones will be selected. The sequential selection of families with intensities of 60% (SG) and 60% (FCG) would promote greater efficiency for the selection of clones in second or third clonal generation. In the case of applying stronger selection intensities for a higher efficiency with sequential selection (SG and FCG) weaker intensities should be applied in the SG and stronger intensity in FCG . Family selection for tuber yield could be practiced in the FCG as long as the selection of clones was not held in contrasting temperature conditions.

Repeatability of family means in early generations of potato under heat stress

The selection of potato clones for yield is usually effective from the second clonal generation. It would however be ideal to select from the seedling generation (SG) or the first clonal generation (FCG). The aim of this study was to evaluate the repeatability of selection at the family level performed in the early generations with the subsequent generations, for tuber yield and specific gravity in the warm season. Thirty families were evaluated in the SG, FCG and the second, third and fourth clonal generation, without any selection. In this way, adjusted means of the 30 families were obtained for each generation. Selections were simulated independently in the different family generations, and then the repeatability of these families among generations verified, using the same selection intensity. The results showed that the family selection in the SG and FCG for specific gravity and in the FCG for tuber yield is efficient, at mild as well as warm temperatures.

Influence of temperature and salinity on germination of eelgrass (Zostera marina L.) seeds

Seagrass restoration as part of ocean ecosystem protection has been launched for many years all over the world, but intensive research on this subject in China has just begun in recent years. Seed broadcasting has been widely accepted as the most potentially useful method for seagrass restoration over large areas. We examined the influence of key environmental factors on seed germination to help promote eelgrass bed restoration. Under anoxic conditions, the influence of temperature and salinity on the germination rate of eelgrass (Zostera marina L.) seeds was examined at different combinations of four temperatures (4, 9, 14, and 24°C) and nine salinities (5 to 45, increment of 5). The effect of significant interaction of temperature and salinity on germination rate was observed (ANOVA) (P<0.001). The highest germination rate (83.3 ± 3.5)% was reached in 8 weeks at 14°C and salinity 5. Higher temperature significantly increased the germination rate at salinity 5 (P<0.001) during the whole observation period except for 24°C, while lower salinity significantly increased the germination rate at 14°C (P<0.001). Although significant interaction was found between temperature and salinity (P<0.001), the influence of salinity was stronger than that of temperature for the germination of eelgrass seeds. These results provide useful information for the propagation of artificial seedlings for seagrass restoration in China.

Growth and nutrient uptake of Citrus rootstock varieties as affected poultry manure and NPK fertilizer in Ibadan, Southwestern Nigeria

Screen house experiment was conducted to determine the optimum rate of organic, inorganic and organo-mineral fertilizers that would enhance the growth and nutrient uptake of citrus rootstock seedlings. Two rootstock varieties [Cleopatra mandarin (Citrus reticulata Blanco) and Rough lemon (Citrus jambhiri Lush)] and ten fertilizer rates [0, 3, 6 and 9 t/ha poultry manure (PM), 0.2, 0.3, and 0.4 t/ha NPK 15-15-15 (NPK), 1.5 t/ha PM+0.2 t/ha NPK, 3 t/ha PM+0.15 t/ha and 4.5 t/ha PM+0.1 t/ha NPK] serve as main and sub-plot treatments respectively in split plot experimental design. Results obtained showed that seedlings grown with 9 t/ha PM and 0.2 t/ha NPK had significantly (p= 0.05) higher plant height, number of leaves, stem diameter and nutrient uptake as compared to other fertilizer treatments throughout the period of investigation. Rough lemon seedlings had significantly higher number of leaves and number of branches compared to Cleopatra mandarin during the period of study. There were no significant differences in dry matter accumulation between the two rootstock types. Since plant height and stem diameter determine the quality of rootstock seedlings, poultry manure at 9 t/ha and NPK fertilizer at 0.2 t/ha are therefore recommended for propagation of citrus seedlings in the screen house.Key words: Spices, Prevalence, Supply, Usage, Profitability, Constraints.

Robotic Sugar Cane Seedling Propagation System in Tissue Culture

Robotic Sugar Cane Seedling Propagation System in Tissue Culture

Optimization of in vitro seed germination of Taraxacum platycarpum

Dandelion (Taraxacum platycarpum) has been widely utilized for medicinal purposes. However, the dandelion seeds are relatively difficult to germinate under cultivation conditions, which hampers seedling propagation of dandelion plants and reduces the opportunity of usage of such a useful medicinal plant. Thus, in this study, in vitro conditions for the dandelion seed germination were optimized to enhance the germination rate. In seed washing steps, the sequential treatments with 20% of ethanol, 20% of NaOCl, and distilled water avoided microbial contamination with the highest in vitro germination rate (67.5%) from seeds sown in germination media. The media supplemented with 1.4 g/L of MS salts and 1% of sucrose significantly enhanced the germination rate compared to the media with 4.4 g/L of MS and 3% of sucrose. Sowing the seeds vertically in the optimized media supplement conditions, 1.4 g/L of MS salts and 1% of sucrose, gave the maximum in vitro germination rate (61%), which was almost three times higher than sowing seeds on a soil pot (23%). Our results indicate that the seed washing and sowing methods including germination medium supplements can be optimized to enhance in vitro seed germination of dandelion.

Casuarina research and applications in China

Casuarina trees are planted along the coastal area of the South China as windbreaks, and in agroforestry systems and for wood and fuel wood production. At present, casuarina plantations cover about 300,000 hectares. Casuarina equisetifolia, C. cunninghamiana, C. glauca and C. junghuhniana are the most commonly planted species. A simple technique for the mass propagation of casuarina seedlings has been developed using cuttings rooted in water. A series of field trials have been carried with various Casuarina species, provenances and clones to screen for adaptability to biotic and abiotic stresses in different areas of China. Experiments conducted in the nursery, glasshouse and field showed that ectomycorrhizal (ECTM), arbuscular mycorrhizal (AM) fungi or Frankia symbiotic associations play an important role in improved growth of managed casuarina plantations.

Subirrigation of Quercus rubra Seedlings: Nursery Stock Quality, Media Chemistry, and Early Field Performance

Container seedling production systems for forest tree nurseries are challenged by the need for judicious water consumption. Subirrigation systems may provide an alternative to overhead systems by mitigating water use, yet remain relatively untested for propagation of forest tree seedlings. We evaluated effects of overhead versus subirrigation under varying media (40:60, 60:40, and 80:20 peat:perlite) and fertilization (0 or 1.2 g nitrogen/plant) regimes on nursery development and first-year field performance of northern red oak (Quercus rubra L.) seedlings. Fertilization increased aboveground biomass production and nutrient content, but decreased root dry weight. Relative to overhead-irrigated seedlings, subirrigation increased red oak seedling aboveground biomass production as well as above- and belowground nitrogen content under fertilized conditions. Media had no effect on plant response. Subirrigation increased electrical conductivity (5 dS·m−1 greater) and decreased pH in the upper media zone (0 to 5 cm from top), whereas the opposite effect was found in the lower zone. Nursery fertilization was associated with reduced field survival and growth, which may have been the result of transplant stress resulting from higher shoot:root. Subirrigated seedlings had greater field diameter growth. Our results suggest that subirrigation could serve as a viable alternative to overhead systems in container propagation of hardwood seedlings.

Growing tropical tree planting stock in root trainers: Cell volume, seedling density and growing media

The influence of root trainer cell volume and seedling density, and composition of growing media was examined in relation to morphological, biomass and seedling quality parameters of four-month old planting stock of three tropical broadleaved tree species viz., Acacia catechu, Azadiractha indica and Pongamia pinnata. The study revealed that a cell volume of 90 cm3 was not sufficient for proper seedling growth of A. catechu and A. indica. However, clear-cut superiority of 300 cm3 cell volume was evident only in the case of A. indica. It appeared that root trainer pots of 150 cm3 cell volume were suitable for growth of planting stock of A. catechu and P. pinnata and 300 cm3 cell volume for A. indica. Significant differences in the growth of planting stocks were observed among growing media treatments. Overall the tree species exhibited fast growth and high biomass as well as favorable seeding quality in growing media containing 80% compost with either sand (A. catechu and A. indica) or soil (P. pinnata) than the other treatments having 50%, 60% or 100% compost.

Note on organic dormancy of estuarine Ruppia maritima L. seeds

Information on seed dormancy is one of the primary requirements for successful seedling propagation of submerged aquatics and seagrass. Studies on Ruppiamaritima seed germination have been done, but the presence, requirements, and the types of dormancy have not been well understood. A laboratory study was conducted to understand presence and types of organic dormancy of the seeds of estuarine R. maritima collected from Lake Pontchartrain, Louisiana, USA. Our study results indicate that the brackish estuarine R. maritima population produces seeds that do not have any noticeable initial morphological, physical, and physiological dormancy. Although dry stratification reduced seed viability and final germination rates, drying seems to induce an earlier germination in R. maritima. Desiccation also appears to induce an environmental dormancy that can be disrupted by exposure to water. Further study on environmental dormancy is needed to provide information to develop methods for long-term seed storage that can be employed in greenhouse seedling propagation.

EFFECT OF COLD TREATMENT TIME ON STEM-DISC CULTURE OF GARLIC (ALLIUM SATIVUM L.)

ISHS XXVII International Horticultural Congress - IHC2006: International Symposium on Plant Biotechnology: From Bench to Commercialization EFFECT OF COLD TREATMENT TIME ON STEM-DISC CULTURE OF GARLIC (ALLIUM SATIVUM L.)

Introduction of asymbiotically propagated seedlings of Cephalanthera falcata (Orchidaceae) into natural habitat and investigation of colonized mycorrhizal fungi

AbstractAsymbiotic seedling propagation and introduction of seedlings into a natural habitat were achieved for Cephalanthera falcata. For immature seeds collected 65 days after pollination, high germination rate (av. 50%) was achieved on Hyponex agar medium plates. Root development occurred in about 10% of the protocorms 5 months after seed sowing. Rooted protocorms were transferred to a culture bottle containing 100 ml of the Hyponex agar medium and incubated continually. In about 30% of the transferred individuals, shoot height reached 1.5–2 cm 8 months after the transfer. After acclimatization in wet vermiculite at 4°C for 6 months, 135 individuals were planted in a natural stand of C. falcata in mid February 2001. Shoot appearance rate was 44.4% at the first year and flowering was noted in some plants. At the fifth year, shoots with an average height of 21.6 cm still appeared in four plants, and flowering was noted in three of them. Colonization of mycorrhizal fungi was examined in two of them as well as one wild plant, in which the mycorrhizal fungi were identified to be in Thelephoraceae or Russulaceae. These fungi are known to form ectomycorrhiza with trees, and thus a tripartnership symbiosis consisting of C. falcata, mycorrhizal fungi and trees was suggested. The involvement of ectomycorrhizal fungi might be the reason for the low survival rate in the field experiment, because the distribution of ectomycorrhizal fungi relevant to this orchid is assumed to be uneven. The possibility of introducing artificially propagated orchids into natural habitats was discussed.

Early development ofChondrus ocellatus holm (Gigartinaceae, Rhodophyta)

Chondrus is an economically important red algae widely used for food and biochemical purpose. It early development is crucial for the culture and seedling propagation. We chose tetraspores and carpospores ofChondrus ocellatus as examples for experiment of the culture, induction and release in laboratory condition, aiming to understand early development ofC. ocellatus and to apply in seedling production. MatureC. ocellatus were collected in Qingdao, China, from Nov. to Dec. 2004. After the gametophyte and tetrasporophyte were brushed and washed with sterilized seawater, the algal materials were treated in 1.5% KI for 20 min, then were dried for 1h to stimulate the releasing of spores. After the spores released overnight, it were cultured in PES medium, incubated at 18 °C, 10±2 μmol/(m2·s1) in 12∶12h (light: dark). The observation and recording under microscope were carried out. Continuous observation of the early development showed that both tetraspore and carpospore are similar to each other. In general, three stages of the early development were shown being division, discoid crust and seedling stages. To the division stage, the most obvious feature was the increasing of cell number; during the discoid crust stage, the discoid crust had a three-dimensional axis, and it began to differentiate into two types of cells: the basal cells and the apical cells; and to the seedling stage, several protuberances-like appeared on the discoid crusts and formed juvenile seedlings. Carpospores and tetraspores exhibited a similar development process that included division stage, discoid crust stage and seedling stage.

INFLUENCE OF PLUG CELL SIZE FOR ROOT VIGOR AND SEEDLING QUALITY ON GRAFT WATERMELON SEEDLING

INFLUENCE OF PLUG CELL SIZE FOR ROOT VIGOR AND SEEDLING QUALITY ON GRAFT WATERMELON SEEDLING

STOCK QUALITY OF BLACK WALNUT (JUGLANS NIGRA) SEEDLINGS AS AFFECTED BY HALF-SIB SEED SOURCE AND NURSERY SOWING DENSITY

Morphological quality of black walnut (Juglans nigra L.) seedlings largely dictates their capacity to establish well in plantations and their performance potential for use as rootstocks in grafting. Larger seedlings and rootstocks, attained from propagation at relatively low nursery sowing densities, have comparatively more expansive root systems for exploitation of soil resources and greater nutrient/carbohydrate reserves to support aboveground growth. The relative role of genetic selection in dictating morphological quality of nursery-grown black walnut seedlings, however, has not been thoroughly documented. We collected seed from three half-sib families (A, B, C) of black walnut in Indiana, USA which were sown as sprouted seeds into bareroot nursery beds at three sowing densities (L, 11.2 m -2 ; M, 24.2 m -2 ; H, 29.4 m -2 ). Sowing density significantly affected mean shoot height (H > M > L) and root volume (L > M > H), but not stem diameter. Shoot height was increased by 14.4 cm (43%) in H vs. L and root volume was increased by 32 cm 3 (39%) in L vs. H. Seedling response to family selection was significant for height, root volume, and stem diameter (C > B > A). The magnitude of the difference in response was greater for family selection compared to nursery sowing density, as height and root volume were increased by 15.2 cm (46%) and 44 cm 3 (60%) in C vs. A, respectively. Further, family C had greater mean stem diameter and root volume in H than did family A in L; mean height for these two families were about equal between H and L. Our results suggest that identification of superior genetic sources may be relatively more important than sowing density in nursery propagation of high quality black walnut seedlings.

Microbial Recolonization of Compost After Peak Heating Needed for the Rapid Development of Damping-Off Suppression

Compost removed from the hot (>55°C) core of yard trimmings compost piles was incubated under sterile conditions to observe if suppression could develop due to cooling, or if inoculation with an exogenous source of microbes is a critical factor. Suppression of damping-off caused by P. ultimum did not develop in the cooled compost over seven days of incubation, but compost inoculated 10% v/v with cured yard trimmings compost became suppressive after incubating three to five days. This indicated that the microbial community surviving thermophilic composting is not sufficient to support damping-off suppression and that recolonization of this material is needed to rapidly and consistently produce Pythium suppressive compost for use in greenhouse propagation of seedlings.

The role of the cell cycle machinery in resumption of postembryonic development.

Cell cycle activity is required for plant growth and development, but its involvement in the early events that initiate seedling development remains to be clarified. We performed experiments aimed at understanding when cell cycle progression is activated during seed germination, and what its contribution is for proper seedling establishment. To this end, the spatial and temporal expression profiles of a large set of cell cycle control genes in germinating seeds of Arabidopsis (Arabidopsis thaliana) and white cabbage (Brassica oleracea) were analyzed. The in vivo behavior of the microtubular cytoskeleton was monitored during Arabidopsis seed germination. Flow cytometry of Arabidopsis germinating seeds indicated that DNA replication was mainly initiated at the onset of root protrusion, when germination reached its end. Expression analysis of cell cycle genes with mRNA in situ localization, beta-glucuronidase assays, and semiquantitative reverse transcription-polymerase chain reaction showed that transcription of most cell cycle genes was detected only after completion of germination. In vivo green fluorescent protein analysis of the microtubule cytoskeleton demonstrated that mitosis-specific microtubule arrays occurred only when the radicle had started to protrude, although the assembly of the microtubular cytoskeleton was promptly activated once germination was initiated. Thus, seed germination involves the synthesis and/or activation of a reduced number of core cell cycle proteins, which only trigger DNA replication, but is not sufficient to drive cells into mitosis. Mitotic divisions are observed only after the radicle has protruded and presumably rely on the de novo production of other cell cycle regulators.

Modern concepts of agricultural research : Ripples and options for conservation agriculture and resource use efficiency

India witnessed self sufficiency in food production by shifting from the traditional organic to chemical-industrial agriculture in the second half of the past century. The production levels plateaud and several challenges of soil- health, crop production and environment have become critical in the new millennium. This need paradigm shifts in agricultural practices and research priorities. Systems Rice intensification conserves water, but it is difficult to practice. Organic farming is eco-friendly but, organic source of nutrients are not sufficient to meet the nutrient re- quirement of crops and the yield reduction is substantial. It has little scope for farmers to export the produce to de- veloped countries after meeting the standards of trade and cumbersome procedures. The integrated supply of nu- trients is potential to sustain the crop yields and restore the soil-health. The transgenic crops opened new vistas in agricultural production. But, such genetically modified crops are frequently unstable and inactivated. They lose the newly acquired traits due to gene silencing. The cell and tissue culture techniques may substitute the traditional crops for the production of food like starch, protein and fats in fermentation tanks. The nanotechnology is likely to revolutionize the agricultural production system. Nutrition with desired elements and flavor stored in the capsules burst open in the stomach and deliver the nutrients in quantities needed by the organ. Similarly, they release the toxins in the stomach of the harmful insects of crop plants. Nano-sensors will alert the farmers before the occur- rence of the pest, disease or nutrient deficiency and damage to the crops. The resource conservation technologies for anaerobic crops after the harvest of aerobic rice save expenses and time for land preparation. This will facili- tate early sowing of the crops after the harvest of rice on the carry over soil moisture or a shallow irrigation. The use of heavy machinery for sowing may compact the soil in the long run. The residue on the soil surface add or- ganic matter but, it is also likely that it may hinder proper seedling growth. The rice stubbles may harbour the harm- ful pests and disease inoculums, refuge the rats and invite the snake problem.

Effect of preharvest desiccants on Group IVGlycine maxseed viability

The effect of two commonly used desiccant tank mixtures on Glycine max seed production and viability when applied at G. max growth stages R5 to R8 (R5 = beginning pod fill, R6 = full green pod, R7 = beginning maturity, R8 = full maturity) was evaluated. Two mid-Group IV G. max cultivars, one conventional (‘Northrup King 4260’) and one glyphosate-tolerant (‘Asgrow 4701RR’), were evaluated. Tank mixtures containing either glyphosate + sodium chlorate or paraquat + sodium chlorate + surfactant reduced yield, seed weight, and subsequent germination, emergence, and seedling growth when applied at R5 or R6 to either G. max cultivar. Glyphosate + sodium chlorate applied at R7 reduced germination of the glyphosate-tolerant cultivar. When applied at R6 or R7, glyphosate + sodium chlorate reduced the next generation's seedling length compared to paraquat + sodium chlorate. Glyphosate + sodium chlorate increased the number of abnormal seedlings produced in the conventional cultivar compared to paraquat + sodium chlorate. These results indicate that preharvest desiccant applications should not be made prior to G. max maturity (R7).