Weight Of Microtubers Research Articles

THE INFLUENCE OF BIOMASS CONCENTRATION OF CYANOBACTERIA ON SHOOT MULTIPLICATION OF POTATO PLANT, DESIREE CULTIVAR, IN VITRO

This study was conducted to determine the optimum concentration of the biomass of the cyanobacteria (Oscillatoria tenuis) which supports the MS medium prepared for shoot multiplication and rooting of potato plant Desiree cultivar from the culture of sprout explants via in vitro. The results showed that all concentrations of the cyanobacteria biomass extract + MS medium led to a 100% response to shoot formation after 60 days of culture. The 60% of the cyanobacteria biomass extract to the MS medium led to recording the largest number of shoots, reaching 8.8 shoots per explant, The 20% and 40% cyanobacteria biomass concentrations + MS medium treatments were significantly superior in average shoot length and number of leaves compared to the other two treatments, which amounted to 10.02 cm and 5.1 leaves per shoot and 10.48 cm and 5.0 leaves per shoot, respectively. The control treatment and the 20% cyanobacteria biomass concentration + MS Medium treatment did not produce any stolons from the shoots after 60 days of culture. The 40% and 60% cyanobacteria biomass concentration + MS medium treatments had stolons growing from the shoot site in contact with the nutrient medium. The stolon tips began to swell until microtubers were formed 60 days after culturing. The 60% cyanobacteria biomass concentration + MS Medium treatment was significantly superior in the average number of stolons, the number of microtubers, and the microtuber weight, which amounted to 4.6 stolons per shoot, 4.6 stolons per shoot, and 0.32g, respectively. The shoots were cultured in all treatments responded to rooting 60 days after culturing. The treatment 60% cyanobacteria biomass concentration + MS medium recorded the highest response to rooting of the shoots, the average number of roots, and root length which reached 100%, 5.8 roots per shoot, and. 6.2 cm, respectively.

Improvement of potato (Solanum tuberosum L.) micro-tubers formation as effected by nano-particles in-vitro

Background Applying nano-fertilizers in the agricultural sector may lead to sustainable development through lower inputs and waste generation, diminishing nutrient losses, and increasing nutrient use efficiency by releasing nutrients at a suitable rate for plant demand compared with conventional chemical fertilizers. Objective The current study’s objective was to develop the ideal procedure for the in vitro creation of virus-free micro-tubers of two potato cultivars using varied doses of phosphorus and potassium nanoparticles (K-NPs) added to the Murashige and Skoog (MS) medium. Materials and methods The research was conducted at the Tissue Culture Laboratory, Vegetable Crops Department, Faculty of Agriculture, Cairo University, Egypt, from January 2020 to July 2021. The meristem tips of two potato cultivars were excised and cultured in solid MS medium supplemented with sucrose and agar. The multiplication stage involved re-propagation of the cultivars using nodal segments, which were cultured on MS medium. Results and conclusion The effects of potassium 25, 35, and 45 mM or phosphorus 2, 3, and 4 mM nanoparticles on in-vitro micro-tuber formation and growth of two potato cultivars (Lady Rosetta and Spunta) were cultured. Data on the number of branches, plant length, and number of leaflets were recorded after 40 days of culture. The number of micro-tubers/jar, and the fresh weight of micro-tubers were also determined. 25 mM potassium nanoparticles (K-NPs) resulted in the highest number of tubers for both cultivars, while the concentrations (35 mM and 45 mM) decreased tuber formation. For phosphorus nanoparticles (P-NPS), 4 mM resulted in the highest number of tubers and root lengths for both cultivars.

In vitro propagation and microtuberization of potato (Solanum tuberosum L.) Spunta variety in Lebanon

One of the factors that causes low productivity of potatoes in Lebanon is the limited availability of certified seeds. The aim of this study was to establish a rapid protocol for in vitro propagation and microtuberization of potato (Solanum tuberosum L.) of Spunta variety. Meristems culture associated to thermotherapy (one month/37°C) constituted the first step. The highest percentage of reactive meristem (92%) was observed on MS medium devoid of growth regulators while MS medium containing Kin 0.4 mg.l-1, GA3 0.5 mg.l-1 and IBA 0.5 mg.l-1 yielded the highest average number of shootlets (7.8) in the seventh subculture. The lowest number of days obtained for microtuber formation was 10 and the highest average number of microtuber (1.49) was obtained with shootlets incubated under C2 culture conditions (16-h day/8-h night for initial 7 days at 25±2°C; for remaining period: continuous dark at 17±2°C). Contrary the highest microtubers average length (10.75 mm), average width (7.41 mm) and average weight (646.26 mg) were produced under C1 culture conditions (16-h day/8-h night at 25±2°C). Medium supplemented with 5 mg.l-1 BAP and 6% sucrose presented the highest average number of microtubers of 2.36 and 1.94 respectively. Type and concentration of cytokines and sucrose concentration did not have significant effect on the average length, width and weight of microtubers produced.

In vitro micro-tuberization in Bunium persicum with different media and sucrose concentrations

Bunium persicum (Boiss.) B. Fedtsch. is one of economically important member of the Apiaceae family with a tuberous root. Production of this plant is restricted due to seed dormancy and long juvenile time. The objective of this study was to determine the best media and optimum concentration of sucrose for in vitro microtuberization of Black Zira. Therefore, different basal media (Murashige and Skoog (MS), Woody Plant Medium (WPM), Gamborg’s B5, and Gupta and Durzan’s DCR) with 3% sucrose were used for microtuber induction. Then best media was tested by varying concentrations of sucrose (3, 6, 9, and 12%) to increase morphological characteristics diameter and weight of microtubers. The experiment was done in a Randomized Complete Block Design with four treatments and 8 replications per treatment. According to the results obtained in this study, the highest mean of the root length (4.5196 cm), tuber length (1.175 cm), tuber width (0.3575 cm), tuber diameter (4.1 mm), and tuber weight (0.1472 g) after six weeks was observed in the WPM medium. Among the four concentrations of sucrose in WPM medium supplemented with 6% sucrose indicated a better response than the other concentrations in terms of microtuber diameter (7.675 mm), and weight (0.2687 g) average and was found optimum. Therefore, the WPM was recognized as the best medium for micro-tuberization.

Factors affecting in vitro tuberization of potato

BackgroundPotato (Solanum tuberosum L.) is one of the most economically important annual vegetable crops. Microtubers can be produced, stored around year and directly transported to market without transferring to fresh media and without acclimatization. Thus reducing the field cycle to obtain sufficient number of seed potatoes and a high level of healthy materials. The aim of this study was to investigate effects of different combinations and concentrations of growth regulators i.e., kinetin (2.5 mg/l) and coumarin (20, 40 and 60 mg/l) alone or in addition to varied concentrations of sucrose (30, 60 and 90 g/l) on in vitro tuberization of potato (Solanum tuberosum) cv. Diamount.ResultsThe plantlets were propagated using single-node cuttings cultured on Murashige and Skoog medium containing 0.04 mg/l kinetin and 1.0 mg/l IAA. Shoots (6–7 nodes) from the previous step were cultured into medium supplemented with a factorial combination of sucrose concentrations (30, 60 and 90 g/l), coumarin concentrations (0, 20, 40, and 60 mg/l) and two concentrations of kinetin (0 and 2.5 mg/l). Our results showed that kinetin – induced medium have slightly effect to improve tuberization in vitro. But when kinetin was combined with sucrose, this effect was better when raised sucrose concentration from 30 or 60 to 90 g/l. The highest percentage of tuberization after 8 weeks, highest number of microtuber were obtained with high concentration of sucrose (90 g/l) together with dark condition, at 18–20 °C. Also, the highest concentration of sucrose significantly increased the fresh weight of microtuber. In case of coumarin, results revealed that it has important effect on tuber initiation especially with concentrations 20 mg/l and 40 mg/l; otherwise, the initiation period was minimized after adding kinetin. So, the plantlets must be continuously incubated in coumarin –induce medium plus kinetin for 8 weeks to affect the tuberization response. Also, all the other characters of tuberization process on coumarin-inducing medium could be improved by increasing sucrose concentration to 9 g/l.ConclusionsGenerally, results pointed out that the treatment which consists of kinetin (2.5 mg/l) plus 90 g/l sucrose and 20 mg/l coumarin has the best characteristics of in vitro micro-tuberization.

Pengaruh Pemberian Pencahayaan dan Konsentrasi Sukrosa Terhadap Pertumbuhan dan Produksi Umbi Mikro Kentang (Solanum Tuberosum L.)

This study aims to determine the effect of the concentration of sucrose and lighting on the growth and production of potato micro tubers. This research was conducted at the Tissue Culture Biotechnology Laboratory of PT. BISI International Tbk. The treatments given were lighting settings in the incubation room and giving different concentrations of sucrose on basic media. This study used a completely randomized design method with 5 replications. Data were analyzed with Anova and further tested with BNJ. Observation results showed that bright light and a sucrose concentration of 80 g/L gave the best results on the growth of potato plantlets aged 14 to 70 days after planting. Observation of the number of micro tubers, weight of micro tubers, and diameter of micro tubers showed that the combination of dark light treatment and a sucrose concentration of 120 g/L resulted in the highest average value

Effect of photoperiod and KNO3 concentration on the induction and development of potato (Solanum tuberosum) microtuber in vitro

Abstract. Choirunnisa JP, Wardana R. 2021. Effect of photoperiod and KNO3 concentration on the induction and development of potato (Solanum tuberosum) microtuber in vitro. Cell Biol Dev 5: 70-75. Potato (Solanum tuberosum L.) is a carbohydrate source plant that was developed as an alternative to food diversification. The availability of quality potato seeds is very limited due to the high attack rate of bacteria and viruses. The demand for potato seeds can be fulfilled by developing potato microtuber through the application of plant tissue culture. The purpose of this research was to determine the response of potato microtuber formation with different photoperiods and KNO3 concentrations. This study design uses a factorial Completely Randomized Design (CRD) with 5 replicates. The first factor is 3 levels of photoperiod (8 hours/day, 12 hours/day, 16 hours/day). The second factor is 3 levels of KNO3 (1900 mg/L, 2850 mg/L, 3800 mg/L). The study was conducted by observing the age of microtubers initiation, number of shoots, number of roots, number of microtubers, the diameter of microtubers, and wet weight of microtubers were analyzed using SPSS. The results showed that the combination treatment of 8 hours/day photoperiod and KNO3 concentration of 3800 mg/L could accelerate the initiation of microtubers at 8 DAP (Days After Planting). The concentration of 3800 mg/L KNO3 can increase the number of roots and microtubers, the diameter of microtubers, and the wet weight of microtubers. The highest diameter of microtubers (17.89 mm) and the highest wet weight of microtubers (278.81 mg) were found in the photoperiod of 16 hours/day. This study concludes that the higher concentration of KNO3 and the longer photoperiod could be used for the induction and development of potato microtubers, while the short photoperiod could be used to accelerate microtubers initiation

Effect of Kinetin on Growth and Development of Microtubers of Potato (Solanum Tuberosum L.)

The present study was conducted at Central Research Potato Institute, Campus, Modipuram, India to assess the effect of kinetin on the growth and development of microtubers formation in vitro in two potato varieties Kufri Bahar and Kufri Surya. The lower concentration of kinetin (0.75 mg/l) showed decreased parameters like the number of microtubers, fresh weight of microtubers, eyes per microtuber. Higher concentration of kinetin (1.5 mg/l and 2.25 mg/l) led to increasing parameters as compared to control but decreased shoot length in both the varieties but kinetin at (2.25 mg/l) concentration gave best results for in vitro microtuberization for quality and yield parameters.

Development of an in vitro Microtuberization and Temporary Immersion Bioreactor System to Evaluate Heat Stress Tolerance in Potatoes (Solanum tuberosum L.).

High temperature (heat) stress reduces tuber yield and quality of potatoes. Screening potatoes for heat tolerance is increasingly important, considering the climate change scenario and expansion of potatoes to countries where heat stress is an issue. In vitro screening for tolerance to abiotic stresses offers several advantages, including quick evaluation of numerous genotypes (clones) in reduced space, controlled environmental conditions (temperature and photoperiod), and free from confounding variables inherent to greenhouse and field conditions. In this study, we explored the feasibility of using a temporary immersion bioreactor system for heat tolerance screening of potatoes. We determined the best hormone-free microtuberizing media for this system (MSG with 8% sucrose) to enhance microtuber number and size. Comparisons of microtubers produced at 30°C as heat treatment, with 16°C as normal condition, allowed to identify heat tolerant and susceptible potato clones. The use of bioreactors allowed distinguishing well-formed (non-deformed) from deformed microtubers. Heat stress increased the total biomass of plant tissues in all the clones. However, the effect of heat stress on microtuber number and weight varied among the clones. Incubation at 30°C decreased the weight and number of non-deformed microtubers in all the clones except for Reveille Russet in which the weight of non-deformed microtubers was significantly increased and the count of non-deformed microtubers was not affected. The potato variety Reveille Russet, which was selected under high-temperature field conditions in Texas, had many non-deformed microtubers per explant and the highest microtuber weight among four clones evaluated under heat stress. We described a faster and reliable in vitro microtuberization system for abiotic stress tolerance screening, identified Reveille Russet as a promising heat-tolerant potato variety, and confirmed Russet Burbank and Atlantic as susceptible heat-tolerant checks.

Effect of Paclobutrazol in micro tuberization of Potato (Solanum tuberosum L.) cultivar Granola Kembang and Repita

The seeds or seedlings are the main key to the success of potato cultivation. So one way to obtain high quality of potato seeds is to do with in vitro plant propagation or tissue culture. The research was conducted at Tissue Culture Laboratory, UPT Seed Horticulture Johor Building Medan, used the completely randomized design with two factors. The first factor was potato cultivar (K1: Granola Kembang, and K2: Repita), and the second factor was paclobutrazol M1 (MS + 0 ppm Paclobutrazol), and M2 (MS + 10 ppm Paclobutrazol). The results showed that the concentration of paclobutrazol significantly affected on the plant height, the number of shoots, the number of micro tuber, the micro tuber diameter, and the fresh weight of micro tuber.

Study on tuberization of Rehmannia glutinosa (Gaertn.) Libosch.

Rehmannia glutinosa (Gaertn.) Libosch. is an herbal plant, which belongs to the Srcophulariaceae family, containing the main active ingredients such as catalpol and verbacoside in its root tubers. In traditional medicine, R. glutinosa tubers have been used in the fresh or dried tuber root or the prepared rehamannia root. They not only possess the comprehensive pharmacological actions in the blood system, endocrine system but also used mainly for anti-tumor treament, immune-enhancement, anti-diabetes, treament for concretion in the urinary tract, etc. R. glutinosa is naturally distributed in China, Korea and Japan. This species was introduced into Viet Nam since 1958 and then planted widely in many the Northern plain and midland provinces. In Vietnam, R. glutinosa produces flowers without seeds, therefore the plant has been mainly propagated by slicing tubers. In this work, we investigated the effect of some plant hormones and sucrose contents on the ability to producing microtubers of R. glutinosa. Experiments were establishmented on the 1/4 MS medium supplemented with 50g/L sucrose. Results showed that auxin (IBA, NAA) had no effect on the in vitro tuber formation of R. glutinosa. The efficiency of using the single BAP or PP333 was low. The highest in vitro tuberization rate of R. glutinosa obtained on the medium supplemented with the combination of BAP (1.0 mg/L) and PP333 (0.3 mg/L), reached 83.33% and the number of tubers/plant was 5.58. The optimal sucrose concentration for increasing the diameter and weight of microtubers was 70 g/L. 100% of plants with tuber-roots survived in the nursery and thrived on the field

English

Two potato varieties namely, kufri bahar and kufri surya were tested for in vitro tuberization response to a same culture medium supplemented with three levels of 6-benzly aminopurine (0.75, 1.5 and 2.25 mg/L) in a completely randomized block design. The study was conducted in the Central Potato Research Institute (CPRI), Modipuram, Meerut Campus, and India during the period of 2012 to 2013 and 2013-2014. The objective was to determine optimum concentration of 6-benzly aminopurine for tuberization. Both varieties, exhibited a better response when the culture medium supplemented with 2.25 mg/L of 6-benzyl aminopurine than the other concentrations and control for mean values of number of days for tuber initiation microtuber number, fresh weight of microtubers and number of eyes per microtuber was found optimum and it may be useful to enhance tuber quality as well as crop growth under in vitro conditions at farmer and industrial levels. Key words: In vitro plantlets, potato cultivars, 6- benzyl aminopurine, in vitro plants.

Addition of White Light to Monochromatic Red and Blue Lights Alters the Formation, Growth, and Dormancy of In Vitro-grown Solanum tuberosum L. Microtubers

Monochromatic light and wide-band white light both affect plant growth and development. However, the different effects between monochromatic light and addition white light to monochromatic light on the formation, growth, and dormancy of microtubers have not been fully explored. Therefore, we evaluated these effects using in vitro potatoes grown under pure blue and red lights and a combination of blue light and red light supplemented with white light, respectively. Current results suggested that light spectra influenced microtuber formation, growth, and dormancy by regulating potato plantlet morphogenesis, affecting the synthesis and transportation of photosynthetic metabolites, and altering the accumulation and distribution of biomass in various plant tissues. Monochromatic lights and the combined spectra had differing effects. For instance, monochromatic red light induced the growth of more microtubers, whereas addition white light to red light decreased number but increased weight of microtubers. Meanwhile, monochromatic blue light facilitated tuber growth, whereas addition white light to blue light decreased microtubers weight but increased microtuber number. In addition, composite lights of addition white light to monochromatic red and blue lights both extended the dormancy period, and monochromatic blue light shortened the dormancy period of microtubers >300 mg. Therefore, in microtuber agricultural production, specific light conditions may be applied at different growth stages of in vitro potatoes to increase the number of effective microtubers (>50 mg) and to satisfy storing requirement of seed microtubers.

Effect of adding growth regulators benzyl adenine (BA) and kinetin (Kin) on production of potato (spunta) micro tuber

This experiment was carried out in plant tissue culture laboratory a part of bio technology research center (BTRC) , while the main aim for this experiment was to investigate the effects of using plant growth regulators on potato micro tuber formation for Sponta potato variety throw plant tissue culture method , In the beginning micro propagation operations were done to the target potato variety in order to obtain enough number of plants samples in free contamination MS media , while different concentrations of BA and Kin plant growth regulators ( 0 , 1 , 2 , 3 mg/l ) were used in this experiment , the plant growth regulators BA ,Kin were added to MS media contain 60g/l sucrose during micro tuber formation stage . the results of this study showed that the treatment of (5mg/l Kin ) obtained the best results and this treatment gave the highest tuber production compared with other treatments , furthermore this treatment ( 5mg/l Kin) gave the highest number of produced potato tuber and the highest weight of produced tuber compared with other used treatments , while the average number of produced micro tubers arrived to 4.9 tuber for each plant and the average weight for obtained potato tuber arrived to 0.84 g which was higher than other weight of micro tuber produced from the other treatments .

EFFECT OF PH AND PHOSPHORUS CONCENTRATION ON POTATO MICROTUBERIZATION

An in vitro study was conducted to investigate the effect of phosphorus concentration and pH on microtuberization of two potato varieties. Diamant variety produced higher microtuber number while Spunta gave heavier microtubers. Increasing phosphorus concentration to 2 mM gave the best results of microtuber number and average microtuber weight per jar. Moreover, lowering pH for 24 hr. produced higher microtuber number and average microtuber weight per jar. The results demonstrated that increasing phosphorus concentration and pH temporary lowering could improve microtubers number and weight magnifying the possibility of microtuber utilization in seed potato programs.

Physiological Effect of Potato Genotypes and Salicylic Acid on Plantlets Growth and Microtuber Production under Salt Stress

This study was conducted to investigate the effectiveness of SA (10 and 100 μmol) for induction of salinity tolerance of two potato genotypes “Proventa” and line “97-980” during vegetative and micro-tuberization stages. Results showed that decreasing of plantlet weight and length as well as microtuber weight under saline conditions differed according to genotypes and SA concentration. Although line “97-980” had low percentage of decreasing in weight and length of plantlets compared to “Proventa” under saline condition, Proventa cv. Gave high microtubers weight. Line 97-980 recorded high reducing sugars, phenolics, proline, amino acids and proteins as well as high activity of peroxidase (POD). On contrary, “Proventa” had high concentration of total chlorophylls and high activity of superoxide dismutase(SOD) and catalase (CAT).The decrease in plantlets growth was lower in line 97-980 compared to” Proventa” under low concentration of SA. Microtubers weight in “Proventa” was higher with addition of 10 μmol through increment in most investigated biochemical compounds and high antioxidants enzymes activity. It may be concluded that high content of reducing sugars, phenolics, proline, amino acids, proteins as well as high activity of POD could work as selectable markers for in vitro potato tolerance to salinity. Addition of low concentration of SA had beneficial effect on physiological

IN VITRO MICROTUBERIZATION OF POTATO: EFFECT OF EXPLANT DENSITY, SOURCE, AND GENOTYPE

This study was conducted to examine explant density and source on production of in vitro potato microtubers, as well as survey of different newly-introduced potato cultivars for their microtuberization capacity at the Plant Tissue Culture Facility of the Department of Horticulture, Suez Canal University between 2014 until 2016. Results indicated that as culture density from single node explants increased, microtuber number and yield/petri dish were also increased. However, at the lowest density (10 explants/petri dish), the % tuberization and the average microtuber weight increased significantly over the higher densities (20, 25 and 30 explants/petri dish). Potato microtuber production from plantlets grown in vitroon microtuberization induction medium (liquid over solid media) was also studied using 5, 10 and 15 plantlets per jar.Results showed that microtuber number and yield/jar increased gradually with increasing plantlet density. However, on per plantlet basis, microtuber number increased at the lowest density. Microtuber yield/jar increased significantly at the highest density (1099 mg/jar) compared to 563.6 mg/jar at the lowest density. Average microtuber weight was also affected by culture density and genotype. At the lowest density, microtubers were significantly heavier than at the high density, and the cv. 'Safrane' recorded the highest weight per microtuber. Regarding the effect of explant source on microtuber production, results indicated that the use of single node explants derived from the top of the plantlet produced more microtubers than those taken from the basal part, or 3 node segments. Explant source also affected microtuber yield/dish. Single nodes from the top produced the highest yield compared to 3-nodes segment from the top (205 vs. 104.8 mg). The highest mean microtuber fresh weight was obtained from the culture of 3-node layered segment from the plantlet base, while single nodes from the top recorded lower microtuber fresh weight. The highest microtuber fresh weight was recorded in cv 'Universa' (114.3 mg) using single nodes from the plantlet base. Differences among the tested potato cultivars in microtuber production were detected.

Formation of potato microtubers in vitro depending on temperature and light intensity

Aim. To specify optimal techniques infl uencing the increase of intensity of potato tuber formation in meristem culture in vitro. Methods. Integrated use of laboratory, mathematical and statistical, calculation and compari- son methods and the method of systematic analysis. Results. The paper represents experimental data about the infl uence of temperature and light intensity on the induction of tuber formation under microclonal reproduction of the health-improved initial material. It proves that the decisive factor in the process of morphogenesis of plants in vitro of the early maturing potato variety Kobza and their productivity is temperature conditions for cultivation. Conclusions. Optimal indexes of productivity and economic effi ciency are maintained by grow- ing test-tube plants under the temperature of cultivation of 14–16 oС and the light intensity of 3,000 lux. The number of microtubers per plant was 1.2 pieces, the weight of an average microtuber was 262,0 mg, the weight of microtubers per plant was 363,7 mg, the number of microtubers weighing more than 350,0 mg was 20,9 %; the cost price of microtubers was 5,31 UAH with the profi tability of 201 %.

Micro-Tuber Production in Diploid and Tetraploid Potato after Gamma Irradiation of <i>in Vitro</i> Cuttings for Mutation Induction

Micro-tubers are important propagules in potato breeding and potato production, and they are also dormant and easily transported and therefore good targets for mutation induction in potato mutation breeding. A prerequisite for mutation breeding is to determine optimal mutation treatments. Therefore, radio-sensitivity tests of a tetraploid and a diploid potato to gamma irradiation were undertaken. Effects of different gamma sources on radio-activity were also studied. In vitro potato cuttings were gamma irradiated using a wide dose range (0, 3, 6, 9, 12, 15 and 20 Gy). The irradiated cuttings were then cultured to induce micro-tubers directly in vitro. Micro-tuber morphotypes were assessed after irradiation of cuttings using three gamma sources with emission activities of 1.8, 7.07 and 139 Gy/min. The diploid species (Solanum verrucosum) was more radio-sensitive than the tetraploid cultivar Desirée (Solanum tuberosum). Gamma dose rates had significant influences on subsequent micro-tuber production at various mutant generations. Effects included reductions in the number, size and weight of micro-tubers produced. Gamma dose was more lethal for the diploid potato genotype and micro-tubers produced were small compared to those produced by the tetraploid genotype after irradiation. Different treatments are recommended for diploid and tetraploid potato irradiation in producing large mutant micro-tuber populations. The mutant micro-tuber populations may then be screened for interesting mutations/trait for both genetics and plant breeding purposes.

Efficient microtuber production of potato in modified nutrient spray bioreactor system

A laboratory scale bioreactor system has been developed using nutrient spray technology for in vitro mass production of potato microtubers. Its effectiveness on the production of microtubers was investigated and compared with conventional liquid and semi-solid culture systems through bioreactor. Optimal culture conditions such as spray intervals, varying concentrations of 6-benzylaminopurine (BAP) and explants density were determined for the NSB. In order to determine optimal spray intervals, liquid medium was sprayed inside the NSB at different intervals (½, 1–4h) of which the 1h interval resulted in the highest number of shoots (3.47) and length (8.99cm). Number of microtubers produced (5.13) was highest with 1h intervals and fresh weight of microtubers (0.90g) was highest for ½h interval. Different concentrations of BAP (0.5, 1.0 and 1.5mg/L) were used to evaluate its effect on microtuberization. It was observed that number and diameter of microtubers were increased (5.31 and 0.96cm) when 0.5mg/L BAP was supplemented in MS medium. We found fresh weight of microtubers (0.97g) was increased when 1.0mg/L BAP were added to the medium. In order to determine suitable explants density, single nodes grouped into five categories e.g 30, 45, 60, 75, and 90 and placed in the NSB system. A density of 60 explants resulted in increases in shoot length (17.5cm) number of internodes (12.5) and with highest amount of chlorophyll (40.2mg/g) as well as with highest number and fresh weight of microtubers (4.43 and 0.89g, respectively). Out of the three culture systems, the NSB performed best where 1.5–2.0 fold increases in shoot growth and microtuberization without hyperhydration. The NSB also produced the highest number (4.67), fresh weight (0.86g) and diameter (0.78cm) of microtubers. From this study we may conclude that the NSB system has good potential for commercial mass production of potato micro-tuber.