Minituber Production Research Articles

IMPROVING PRODUCTION AND CHARACTERS OF POTATO MICROTUBERS AND MINITUBERS

This investigation was carried out during the seasons 2012 and 2013 on potato cv. Diamant at the Tissue Culture Laboratory and the greenhouse of Potato and Vegetatively Propagated Vegetables Department, Horticulture Research Institute, Dokki, Giza, Egypt. The present study aimed to study the effect of the in vitro application of chitosan, calcium chloride and the concentration of ammonium nitrate and potassium nitrate on potato tuberization. In addition, to study the effect of foliar application of chitosan, chelated calcium and potassium silicate on growth and yield of the minituber ex vitro. Results revolved that 500 mg/l chitosan gave the highest values of number of shoots and node/plantlets, number of microtuber, fresh and dry weight of shoots and microtubers fresh weight after 8 weeks from culture in vitro. Furthermore, ex vitro spraying with 500 mg/l chitosan or the mixture of 350 mg/l chelated calcium + 400 mg/l potassium silicate produced the highest values of plant length, leaves number/plant, fresh and dry weight of leaves on 75 days after planting. As well as, minituber characteristics (number of minituber /plant, minituber fresh and dry weight/plant, average minituber weight and weight of minituber /plant according to its size) after 100 days from planting recorded the highest significant values with foliar application of 500 mg/l chitosan or the mixture of 350 mg/l chelated calcium + 400 mg/l potassium silicate. It could be recommended that adding chitosan at 500 mg/l to in vitro microtuber production medium (MS + 8 mg/l BA + 80 g/l sucrose) was preferable to produce microtubers. Also, the ex vitro spraying of 500 mg/l chitosan or the mixture of 350 mg/l chelated calcium plus 400 mg/l potassium silicate could be useful for minituber production and enhancing its yield characteristics.

Effects of plant growth regulators on growth and yield of pre-basic seed potato production under glasshouse condition

A glasshouse experiment was carried out to study the effect of Plant Growth Regulators (PGRs) on the production of pre-basic seed (PBS) potatoes, cv. Janakdev at Khumaltar, (1360 masl) Lalitpur, Nepal during autumn and spring seasons of 2014 and 2015 respectively. Four - week old virus free in vitro plantlets grown in tissue culture laboratory were planted with 20 cm distance between rows and 10 cm between plantlets under glasshouse in completely randomized design. Three growth regulators, paclobutrazol (50 ppm), daminozide (100 ppm), chlormequat chloride (Cycocel) (200 ppm) and simple water as control were used for single foliar spray 6 weeks after transplanting with four replications. Analysis showed that there were significant differences on growth parameters; plant survival, plant uniformity, plant height and yield components; number of minitubers per plant and per square meter in both the seasons. Significantly maximum number of potato minitubers was recorded in growth retardants treated plants as compared to control. Experimental results showed that maximum number of minituber (22.9/plant and 668.2/m2) in autumn and (23.7/plant and 1185.0/m2) in spring season were gained from paclobutrazole spray, which were statistically differed from those of other growth regulators and control. Plants without PGR and treated with daminozide produced the least amount of minituber per unit area. Plant height decreased in all growth regulators over control due to their inhibiting effect on growth of the plants. paclobutrazol significantly reduced plant height but produced larger and heavier minitubers compared to other treatments. Hence, the best PGR for optimum enhancement of minituber number and size was paclobutrazol. The results suggested that paclobutrazol could be used in pre-basic seed potato production, leading to maximum minituber production which ultimately gave higher returns. The study concluded that spraying growth retarding chemicals at grand growth stage checked the excessive vegetative growth and increased the number and size of minituber.SAARC J. Agri., 15(1): 149-160 (2017)

Evaluation of Micro Tuberization Performances of Different Genotypes

Certified potato seed tuber usage is one of the most important steps for production of high yield and quality potatoes. For this reason different seed tuber production methods have been developed. Among these methods, mini tuber production is the most popular one. In order to produce mini tubers, firstly potato plants are produced in vitro, and these plants are transferred to an environmentally-controlled greenhouse. Thus, disease- and virus-free mini tubers are produced as seed tubers. However, in vitro section of mini tuber production creates problems like storage and transfer of in vitro plants, and adaptation period of the plants to greenhouse conditions. In vitro micro tuber (MT) formation has been selected as a solution of these problems. The aim of the study was to produce micro tubers from 15 different genotypes and evaluate their micro tuberization performances to determine the genotype effect on MT formation. 3 varieties, 3 breeding lines and 9 different genotypes from International Potato Center (CIP) were selected for the study. For this purpose, micro tubers are produced in vitro by using Murashige and Skoog (MS) medium supplemented with 8% sucrose and 0.1 mg/L thidiazuron (TDZ). All experiments were conducted under dark conditions and 22/16 °C (8/16 h) temperature cycle. The micro tuberization performances were evaluated according to MT number per plant, MT formation rate (%), MT weight per plant (g), mean MT weight (g), mean MT diameter (mm). Differences between micro tuber production performances of different genotypes were determined and CIP395017.229 was identified as the most promising genotype to produce micro tubers.

English

Quality seed potato is a key factor in enhancing potato yields in Uganda. Available disease-free seed potato accounts for less than 5% of the whole potato seed market demand in Uganda leaving 95% as seed availability gap. This study was conducted to explore the potential of using farmer managed screen houses to alleviate the seed potato availability gap that exists in Uganda. Six screen houses of 7 m × 14 m each with capacity of 1620 plants were set up, three (3) screen houses in Bukimbiri, one (1) in Kisoro, one (1) in Hamurwa and one (1) in Maziba sites. All the sites were managed by trained six famers. Sterilized soil was used to reduce the incidence of pathogens and to ensure that clean mini-tubers were produced. Seed production was done in 2015 for two consecutive seasons (A and B). From the 6 screen houses, a total of 107,638 clean mini-tubers were generated across the sites for both seasons. At multiplication ratio of 1: 9 the generated mini-tubers have the potential of generating 968,742 tubers. This would reduce on existing seed gap for the next season. It was noted during the study that mini-tuber production, vigour and rate of growth varied significantly (P<0.001) across the varieties with ‘Rwangume’ achieving the highest yield in terms of tuber number per plant and height, compared to other 4 varieties (Kiningi, Rwashaki, Kachpot 1 and Victoria). This study showed that production of disease free mini-tuber at farmer level is possible using screen house technology and has a potential of reducing the seed availability gap through production of quality seed that can be accessed by other farmers.   Key words: Seed potato, seed gap, farmer screen houses.

Electrical conductivity of the nutrient solution and plant density in aeroponic production of seed potato under tropical conditions (winter/spring)

ABSTRACT The recent introduction in Brazil of production of quality seed potatoes in hydroponic systems, such as aeroponics, demands studies on the nutritional and crop management. Thus, this study evaluated the influence of electrical conductivity of the nutrient solution and plant density on the seed potato minitubers production in aeroponics system. The Agata and Asterix cultivars were produced in a greenhouse under tropical conditions (winter/spring). The experimental design was a randomized block in a split-split plot design. The plot consisted of 4 electrical conductivities of the nutrient solution (1.0; 2.0; 3.0; and 4.0 dS∙m−1); the subplot, of 4 plant densities (25; 44; 66; and 100 plants∙m−2); and the subsubplot, of the 2 potato cultivars (Ágata and Asterix), totaling 4 blocks. The 2.2 and 2.1 dS∙m−1 electrical conductivities yielded the highest productivity of seed potato minitubers, for Ágata and Asterix cultivars, respectively, regardless of plant density. For both cultivars, the highest yield was observed for the 100 plants∙m−2 density.

Determination of Nutrient Solutions for Potato (Solanum tuberosum L.) Seed Production under Aeroponics Production System

AbstractIn soilless culture like aeroponics, nutrient optimization is the most critical factor to produce high quality and high yield of clean potato seed. Each crop has an optimum nutritional requirement. Even each potato cultivar may require a specific nutrient solution in an aeroponics unit. A nutrient optimization experiment was conducted at Holetta agricultural research center to study the effect of different nutrient solution levels on the physical quality and yield of potato mini-tubers. The treatments were four different nutrient solutions of greenhouse grade macro nutrients measured in (g) for the preparation of 500 liter volume of nutrient solution that is to be restocked when the nutrient tank becomes empty. The nutrient EC and pH were adjusted as per the requirements. A=(118 g CaNO3, 252 g KNO3, 68 g KH2PO4and 100 g MgSO4) ,B=(59 g CaNO3, 126 g KNO3, 68 g KH2PO4and 100 g MgSO4), C=(118 g CaNO3, 252 g KNO3, 68 g KH2PO4and 100 g MgSO4until flowering and reduced by half after flowering), and D=(118 g CaNO3, 252 g KNO3, 136 g KH2PO4and 100 g MgSO4). All treatments included 2.2g of Fe EDTA and 6 g of Fetrilon combi. The potato variety, Belete, was used for the experiment. Acclimatized plantlets were planted randomly in each box of four treatments in CRD design with three replicates. The results showed that each treatment varied in nutrient consumption rate. Treatment A took the highest amount of nutrient (3.29 kg, 28%), treatments B and D consumed the same amount (3.1 kg, 27%), while treatment C consumed the smallest amount (2.02 kg). Roo length was significantly affected by nutrient solutions. Nutrient solution C resulted the maximum root length (300.8 cm), while nutrient solution A produced minimum root length (135.5 cm). Plant height was not significantly affected by nutrient solutions. Small size tubers (<8 g) were not significantly affected by either tuber number or weight. Medium (8-12 g) and large size tubers (>12 g) were significantly affected by nutrient solutions both in number and weight. The maximum tuber numbers was obtained from treatment B. Therefore, the experiment indicated that treatment B represents the optimum nutrient concentration rate to use in an aeroponics minituber production system under Holetta conditions.

Performance of Two Potato Cultivars Derived from In-vitro Plantlets, Mini-tubers and Stem Cuttings Using Aeroponics Technique

An experiment was conducted at KALRO-Tigoni to assess the effect of starter plant material (in-vitro plantlets, stem cuttings and minitubers) on minituber production of two potato cultivars Asante and Tigoni under aeroponic conditions. The experiment was set up in the aeroponic unit at KALRO-Tigoni in randomized complete block design (RCBD) replicated three times. Data were collected at each harvest on the number of minitubers produced per plant; the minitubers were later graded into three weights (0.1-5g, 5.1-12g, >12g). Cultivar Tigoni produced a higher total number of minitubers (49.96) and (52.67) compared to Asante which produced (39.63) and (46.39) minitubers in season one and two respectively. Additionally, in-vitro propagation materials gave the highest number of minitubers (56.44 and 62.94) compared to stem cuttings (43.53 and 51.44) and minitubers (34.42 and 34.19) during the two seasons respectively. The results of this study suggest that the starter materials have a significant effect on the number of potato minitubers produced under the aeroponic system regardless of the potato cultivar. Use of in-vitro plantlets as starter material optimizes minituber production in the aeroponic system. However, the study should be repeated so as to come up with concrete results.

Feasibility studies for two consecutive crops of potato (Solanum tuberosum L.) under aeroponic system in north-western plains of India

There is huge demand for high quality potato seed in India, however, availability is limited due to low multiplication rate. Aeroponics technology is used for fast multiplication of basic seed stocks from in vitro plantlets. To make better use of expensive aeroponics facility, two production cycles of consecutive crops per year were tried. Experiment was conducted at ICAR-Central Potato Research Station, Jalandhar, Punjab, on three varieties and two hardening mediums before planting to aeroponic system for two consecutive crops. Observations were recorded on per cent survival, days taken to tuber initiation, plant height at final harvest, number of minitubers, minitubers weight, haulm fresh and dry weight and root fresh and dry weight on per plant basis. All the three varieties performed well during main season but Kufri Surya emerged as the best performing variety under aeroponics during second consecutive season. Liquid hardening is better for improved plant establishment as well as early initiation of tubers. Therefore, two crops of potato minitubers production are possible with selection of suitable hardening medium and variety.

Hydroponic Minituber Production in Growth Room Conditions and Carry-Over Effects of the Technique on Produced Minitubers

<p>The production of minitubers was implemented with a hydroponic technique in growth rooms and the carry-over effects of the technique on the characteristics of minitubers were studied. As a comparison, minitubers from in vitro plantlets were grown in a peat-based growing medium. The results show that hydroponic production of minitubers is successful in indoor conditions with the cultivars Desiree, Van Gogh and Asterix, when day-time growing temperatures of 19.4 <sup>o</sup>C-26.0 <sup>o</sup>C and night-time temperatures of 17.5 <sup>o</sup>C-22.6 <sup>o</sup>C were used. Photosynthetically active illumination was adequate at 2383-2509 umol m<sup>-2</sup>s<sup>-1</sup>; lighting conditions consisted of 14/10-hour day/night cycles.</p><p>The cultivars Desiree and Van Gogh developed their first tuber three weeks faster than Asterix, and the minituber yield was 4.5 per plant for Desiree, 7.5 for Van Gogh and 4.0 for Asterix. When a peat-based growing medium was used, minituber yields were almost the same but the size of the minitubers was smaller than that of hydroponically produced minitubers. The results of the carry-over experiments showed that conventionally produced minitubers emerged faster, and in terms of foliage development and yielding capacity performed better than hydroponically produced minitubers.</p>

Normes OEPP

Normes <scp>OEPP</scp>

The potato minituber production from microtubers in aeroponic culture

Minituber production by traditional method is an expensive procedure due to limited productivity. In order to increase the multiplication rate of seed material in vitro, multiple techniques have been assayed in the last decades. The aeroponic system is a soilless culture system, where roots are kept in a dark environment saturated with aerosol of nutrient solution. Aeroponics technology is potentially efficient for specific potato cultivars. The aim of this study was to investigate the multiplication rate of microtubers of national cultivars in aeroponics while maintaining weekly intervals between harvests. The total number of harvests was 14 to 15 depending on year. The results of the experiments were analysed with ANOVA and means were separated with the Tukey's test at 5% P-value. The most important parameter of minituber production, their number, was on average 32.5-36.0 per plant and 1268-1396 per m2 depending on cultivar. Number of minitubers was two to three times greater in the case of aeroponic production than by traditional method. A full economic analysis is necessary to prove that this production technique can be put into practice.

Effect of plant density on mini-tuber production potential of potato varieties through micro-plants under net-house in North Eastern Himalayan region

Effect of plant density on mini-tuber production potential of potato varieties through micro-plants under net-house in North Eastern Himalayan region

Normes OEPP EPPO Standards

Normes OEPP EPPO Standards

How Age of Transplants from In Vitro Derived Potato Plantlets Affects Crop Growth and Seed Tuber Yield After Field Transplanting

In vitro produced plantlets are used in potato seed systems for production of minitubers under protected conditions or for production of transplants to be transplanted to the field. Three field experiments were carried out to analyse how transplant age (Age) affected the field performance. In the main experiments, 2-, 3- and 4-week-old transplants of the very early cultivar Gloria (Exp. 1) and the mid-early cultivar Bintje (Exp. 2) were produced in a glasshouse. Exp. 3 was a check experiment in which 2- and 3-week-old transplants of cv. Gloria were produced in growth chambers under conditions that were non-inductive for tuberization (24-h photoperiod, high temperature). Ground cover (GC) was assessed weekly and weights of the tuber and canopy fractions were assessed at 0, 14, 28, 42, 56, 70 and 84 days after transplanting (DAT). Yield analysis [accumulated intercepted radiation (AIR), radiation use efficiency (RUE), total dry weight (TDW), harvest index (HI) and tuber dry matter concentration] was carried out; the fraction dry matter (DM) allocated to the tubers and the canopy was calculated for three 2-week intervals after field transplanting. When raised in the glasshouse, older transplants were more advanced in tuber formation and canopy growth than younger transplants and had a higher GC at transplanting. However, crops from younger transplants produced significantly higher fresh tuber yields than crops from older transplants in the later part of the growing period in Exp. 1; the same trend was observed in Exp. 2. AIR was the most important yield component affected by transplant age; RUE, HI and tuber dry matter concentration were not or not meaningfully affected by transplant age. In the first 2 weeks after field transplanting, a very high percentage of the DM produced (>85%) was allocated to tuber growth in crops from the oldest transplants. This reduced AIR severely. The results show clearly that seed crops from younger transplants will perform better than crops from older transplants or at least perform at par. Implications for transplant production management are discussed.

Shoot growth restriction in dry matter partitioning andminituber production of potato plants

The aim of this research was to determine the effect of shoot growth restriction in the dry matter partitioning and minituber production of potato plants grown in a closed soilless system. Minitubers of the cultivars 'Macaca' and 'Asterix' were planted in the greenhouse in the density of 100 hills m-2, during autumn and spring growing seasons. Growth restriction levels were gotten by pruning shoots at 10, 20 and 30cm height or without pruning. The growth restriction levels were identified by their respective leaf area index. The experiment was a factorial (cultivars x growth restriction x growing season) in a random design, with four replications. Growth restriction affected the dry matter production of potato plants in both growing seasons and cultivars. Pruning potato plants at 30cm is a feasible technique to control leaf area index and it has lower effect on harvest index and number than in dry matter production of minitubers. Growth restriction does not change dry matter partitioning of potato plants grown in soilless system.

Assessment of potato microtuber and in vitro plantlet seed multiplication in field conditions – Growth, development and yield

Microtubers and in vitro plantlets are the basic materials of potato seed production. Minitubers are yield of tubers derived from the first generation of in vitro plantlets or from microtubers. At present the production of minitubers usually takes place under covers – in glasshouse, plastic tunnels and screenhouses. The aim of this research was to assess the possibility of carrying out such multiplications in field conditions. The growth, development and harvesting was estimated in in vitro plantlets, microtubers, minitubers and traditional seed potatoes. Additionally, three terms of in vitro plantlets and microtubers planting in the field were assessed (1st term – second week of April, 2nd term – fourth week of April, 3rd term – last week of June/first week of July). The weather conditions in 2006–2012 impacted greatly on the survival of in vitro plantlets and microtubers planted in a field, especially in the 1st and 3rd terms. In spite of clear differences in the size of planted seed material, the highest reproduction coefficient per one plant was recorded for traditional seed potatoes and microtubers, and the lowest for minitubers. While at the 1st and 2nd terms of planting the average number of tubers from one plant ranged between 6.7 and 8.8, at the 3rd term this value oscillated between 11.2 and 12.4. Analysis of the productivity of particular seed material clearly indicates a much higher share of potentially useful tubers derived from microtubers and in vitro plantlets than of traditional seed potatoes or minitubers. Microtubers and in vitro plantlets planted earlier (1st term of planting) or significantly later (3rd term) produced the greatest minituber yield. Because of a high risk connected with the dying out of plants and maintaining adequate coverage at its earlier planting, the 3rd term of planting of this material was much more favorable. At the same extreme weather conditions (drought and lack of rainfall at the beginning of after planting), which occurred in 2010 contributed to a very strong reduction plants in the field.

A Low Nutrient Solution Temperature and the Application of Stress Treatments Increase Potato Mini-tubers Production in an Aeroponic System

This study was conducted to test the impact of the nutrient solution temperature and the application of different stress treatments at tuberization on several growth variables for two potato cultivars grown in an aeroponic system. At 25 days after transplanting, low pH level, wilting stress and nitrogen withdrawal under warm (24 °C) and cool (18 °C) root-zone temperatures were applied to potato plants cv. Mystere and Chieftain. Significant differences in mini-tuber production, stolon number and length and root length were observed among root zone temperatures, stress treatments and cultivars. Cooling the nutrient solution temperature to 18 °C significantly increased most growth variables and tuber yield for both cultivars. Plants subjected to nitrogen withdrawal at tuberization out-performed plants of the other treatments as well as the control and exhibited faster tuberization, higher mini-tuber number and weight as well as significantly higher root length, stolon number/plant and number of stolon branches/plant. The low pH and wilting treatments reduced plant growth and mini-tuber number/plant. They dramatically increased the number of stolon branches/plant and stolon number respectively. However, this increase did not counteract the negative effects on the other variables. The results of this study demonstrate that a judicious use of these stresses can effectively promote tuberization in aeroponics.

Rooting Potential of Mini-Cuttings for the Production of Potato Plantlets

The production of mini-tubers under soilless cultivation system increased the availability of pathogen-free seed potatoes. The objective of this study was to evaluate the rooting capability of mini-cuttings of potato clones as a function of the irrigation solution and the physiological age of the mother plant, under soilless cultivation system. Potato mini-cuttings were collected from young and mature plants of the cultivars Asterix and Macaca and the advanced clone SMINIA 793101-3. The young plants were newly acclimatized individuals and the mature plants were at the stage of producing mini-tubers. In the first experiment, mini-cuttings originating from summer pruning of mature plants were grown under closed soilless cultivation system irrigated with a nu- trient solution developed for the production of potato mini-tubers and a solution comprised of tap water only. The experiment was conducted in a 3 × 2 factorial arrangement (clones and irrigation solutions) in the complete random design with four replicates of 15 mini-cuttings. In the second experiment, the young and mature mini-cuttings were established under a closed soilless cultivation system irrigated with nutrient solution. The experiment was conducted in a 3 × 2 factorial arrangement (clones and physiological age of the mother plant) in the complete random design with four replicates of 15 mini-cuttings. In both experiments, the percentage of rooting and survival of mini-cuttings, number of roots and length of the longest root were assessed at 21 days of cultivation. Potato mini-cuttings can be rooted under closed soilless cultivation system irrigated with nutrient solution or tap water. Mini-cuttings of young plants have higher rooting capability compared to the ones taken from mature plants. The loss of rooting capability depends upon the potato cultivar.

The effect of in vitro mycorrhization on growth characteristics, changes in endogenous hormones and performance of microplants in potato (Solanum tuberosum L.)

Potato (Solanum tuberosum L.) plantlets were inoculated in vitro with an arbuscular mycorrhizal fungus (Glomus intraradices) and their growth response, performance and endogenous hormonal status evaluated. A factorial experiment based on a completely randomized design consisting of two potato cultivars (Agria and Sante) and four culture media was conducted with four replications. The culture media included non-inoculated Murashige and Skoog (MS) medium (control), inoculated MS medium, inoculated half-strength MS medium and inoculated MS medium without vitamins and sugar. To do inoculation, germinated spores of fungus were transferred to the root zone of plantlets. Colonization percentage, total chlorophyll content, internodes and stolon length, shoot diameter, shoot and root fresh and dry weight, leaf area and the level of three endogenous hormones (total auxins, gibberellins and cytokinins) were determined. In addition, mini-tuber production was assayed quantitatively and qualitatively. Results demonstrated that the effect of two factors on all characteristics including mini-tuber production was different significantly. Interaction between cultivar and inoculation systems was significantly associated with endogen auxins as well as all range of mini-tuber production. The inoculated MS medium showed the better results, but it did not have significant difference to halfstrength MS in terms of plantlet performance and growing parameters. Responses of both cultivars to inoculation were very conspicuous in the production of endogen hormones. Higher endogen hormone levels were associated with elevated growth parameters, greater biomass production and better plantlet performance.

The effect of in vitro mycorrhization on growth characteristics, changes in endogenous hormones and performance of microplants in potato (Solanum tuberosum L.)

Potato (Solanum tuberosum L.) plantlets were inoculated in vitro with an arbuscular mycorrhizal fungus (Glomus intraradices) and their growth response, performance and endogenous hormonal status evaluated. A factorial experiment based on a completely randomized design consisting of two potato cultivars (Agria and Sante) and four culture media was conducted with four replications. The culture media included non-inoculated Murashige and Skoog (MS) medium (control), inoculated MS medium, inoculated half-strength MS medium and inoculated MS medium without vitamins and sugar. To do inoculation, germinated spores of fungus were transferred to the root zone of plantlets. Colonization percentage, total chlorophyll content, internodes and stolon length, shoot diameter, shoot and root fresh and dry weight, leaf area and the level of three endogenous hormones (total auxins, gibberellins and cytokinins) were determined. In addition, mini-tuber production was assayed quantitatively and qualitatively. Results demonstrated that the effect of two factors on all characteristics including mini-tuber production was different significantly. Interaction between cultivar and inoculation systems was significantly associated with endogen auxins as well as all range of mini-tuber production. The inoculated MS medium showed the better results, but it did not have significant difference to half-strength MS in terms of plantlet performance and growing parameters. Responses of both cultivars to inoculation were very conspicuous in the production of endogen hormones. Higher endogen hormone levels were associated with elevated growth parameters, greater biomass production and better plantlet performance.