Minituber Production Research Articles

Can nitrogen reduction be used to increase seed potato minituber production in an aeroponic system?

Decreasing the nitrogen (N) supply in nutrient solutions can reduce the accumulation of plant biomass and increase yield. Little information, however, is available about the amount and proportion of N reduction, especially for different potato cultivars. The objective of this study was thus to determine the effect of N reduction in the nutrient solution (141.2, 106.2, 71.2 and 36.2 mg L−1) at various times (47, 62, 77 and 92 days after transplantation) on two potato cultivars (Agata and Asterix) grown in an aeroponic system. N reduction did not affect biomass accumulation by “Agata” plants but increased minituber yield by 17% compared to a control treatment (141.2 mg L−1). N reduction, though, affected the biomass accumulation by “Asterix” plants but did not affect minituber yield. These findings suggest cultivar specificity of N management (reduction) in plants cultivated aeroponically.

The effect of carbon dioxide on the production of potato minitubers under aeroponic cultivation

The paper presents data on the effect of additional top dressing of potato plants with CO2 at a concentration of 2500 ppm cultivated in aeroponic plants. It was found that the increased concentration of CO2 provides better development of plant shoots (128.6%) and the root system (120.1%) relative to the control: a larger yield (123.7%) with a larger fraction of minicubes is formed, and the number of plants capable of producing 1100-1600 g of minicubes during the cultivation period increases. Additional feeding of CO2 at a concentration of 2500 ppm leads to an increase in the mass of plants, which occurs not due to increased hydration of tissues, but due to the accumulation of dry substances.

Review of different propagation media for potato mini tuber production under screen house

Scarcities of healthy and quality potato tuber seeds are the problem of the production of potatoes in the world. Especially, in developing countries it is a serious problem that cause decline in the production and productivity of the potatoes and hampers the profits of producers. To alleviate this problem, many countries produce the mini tubers in screen house from diseases-free planting materials in pots or seed bade made of pathogen-free media. Most reviewed papers indicated that a media used to grow potato in screen houses are made of a combination of different substrates for the suitability of the crop gown on it as it provides sufficient nutrients, aeration, support, and water. Developed countries use rock wool, vermiculite, peat, and other expensive media made by factories while the underdeveloped use cheap materials that are easily available in their surroundings like forest soil, sand, compost, and FYM (farm yard manure). There is also limited research concerning these materials in developing countries, especially, about the ratio of mixing and types to be mixed. The expensive materials used for pot media making are not found in Ethiopia though there are surplus raw materials. Therefore, this review was conducted to assess the information available about the different screen house growing media used worldwide and conceptualize for future utilization. It is concluded that researchers should work on the availability of healthy and quality tuber seed by increasing the numbers produced in screen house through agronomic and other techniques of production solving problems related to potting media.

The effects of physicochemical properties of hydroponic substrates on the uptake of macronutrients in potato shoot, root and minitubers

Potato (Solanum tuberosum L.) is one of the most important and economical vegetables. Minitubers are small pathogen-free tubers produced from in vitro plantlets after translocation to greenhouse followed by the creation of healthy and high-quality seed tubers. Hydroponic systems increase the production of these potato minitubers. This study investigates the effects of several growth media on elements uptake by potato shoot, root, and minitubers. There were significant correlations between in root, shoot, and minituber elements uptake and the properties of cultivation beds. The perlite + peat moss medium is recommended for hydroponics production of potato minitubers.

The Improvement of Mini Tuber Production of Granola Potato Cultivar in Aeroponics System

Potato is an important food crop in both developed and developing countries and it is the fourth most important food crop after wheat, maize, and rice. Potato production in Indonesia has decreased in recent years, mainly due to the use of low quality tuber seed. The objective of this research was to determine the effect of plant materials, types of nutrients, and planting density on mini tuber formation, as well as to determine the best aeroponics conditions for mini tuber formation of Granola cultivar of potato. This research has been carried out experimentally using a Split-split Plot Design. The main plot was planting materials which consisted of plantlet and knol. The subplot was the type of nutrition media which consisted of Farran nutrition, Otazu nutrition, and AB-commercial mix. The sub-sub-plot was planting density which consisted of 50, 75, and 100 plants/m2. The research results showed that knol planted in aeroponics system on AB-commercial mix at a planting density of 75 plants/m2 resulted in the best mini-tuber production. In this study, for the first time three important factors for potato mini-tuber production have thoroughly been investigated in Indonesia. This finding will be used by Kledung Horticultural Seed Garden, Temanggung, for mass production of high-quality mini-tuber seed, which in turn will provide sufficient tuber seed for the farmer in its surrounding areas. By increasing the production of high-quality tuber seed, it is expected that it will contribute to the improvement of potato productivity and increase Indonesian potato production.

Innovative technology for growing potato minitubers on aerohydroponic devices

Technologies for the production of minitubers use the controllable conditions of the created aerohydroponic device to automate the process at the stages of plant development. The developed new device maximizes the use of the area within 1 m2 and holds 60 pcs of potato plants. The device is an aerohydroponic module (AHM) designed specifically for growing minitubers in closed spaces. Such conditions make it possible to nourish plants and control each selected genotype during the growing season. The controlled device regulates the development processes of meristemic potato sprouts, conducts phenotypic observations in the winter and selects the best genotypes. The created device offers an opportunity to conduct observations in any terrain.

Seed potato minitubers production in a reused substrate

Minituber production is an important step to obtain high-quality seed potatoes. This production is carried out in a greenhouse using a large volume of commercial substrate acquired in specialized trade. An alternative to reduce the volume of substrate purchased for each production of minitubers would be to reuse it, which would be a way to optimize its use. The objective of this study was to evaluate the efficiency of reused substrates in the minituber production. The experiment was conducted in Tapira-MG with the Atlantic potato cultivar. The experimental design was a randomized block with six treatments and four replications, where each plot was represented by a box (0.15 x 0.4 x 0.5m: height, width, and length, respectively) containing substrates. Treatments consisted of formulation 04-14-08 rates (0, 25, 50, 75, and 100 g box-1) added to reused substrate and a control consisting of a new virgin substrate. At 45 days after transplanting, the following characteristics were evaluated: stem size (cm), and quantities of fresh and dry matter of aerial part of plants. Harvesting was performed manually, counting, and calculating the yield of tubers according to class. The reuse substrate with enriched nutrient regardless of the rate, when compared to the use of a new virgin substrate, did not interfere in potato plant development and in the total productivity of minitubers of classes I, II, III, and IV. This can be a feasible alternative for optimizing the use of the virgin substrate. The rate of 25 g box-1 of 4-14-8 is sufficient to provide the needs of potato in nutrients, ensuring high productivity.

Standardization of planting geometry for aeroponic mini-tuber production in potato (Solanum tuberosum)

For optimization of potato (Solanum tuberosum L.) mini-tuber production through aeroponics, an experiment was conducted for the standardization of plant density through varying in-row and intra-row spacing’s in the aeroponic unit of ICAR-Central Potato Research Institute, Shimla, HP, India. The results revealed that the total number of mini-tubers and yield per plant obtained during all the 14 harvests were in general higher at wider intra-row spacing of 15 cm than 10cm in both the inter-row spacing’s, viz. 15 cm as well as 20 cm. On per unit area basis, the number of tubers/ m2 was maximum at the highest plant density (66 plants/m2) achieved with 15 × 10cm spacing, closely followed and at par with plant density of 44 plants/m2 (15 × 15 cm) and minimum with lowest planting density (33 plants/m2) at 20 × 15 cm. Yield/m2 was not affected significantly with the varying plant density, however, the average weight per tuber was significantly higher (1.74g) at the lowest planting density (33 plants/m2) obtained with 20 × 15cm spacing and was statistically at par among rest of the treatments.

An alternative health crop for South Africa: Purple potato mini tuber production as affected by water and nutrient stress

Food security in South Africa ranks as one of the top ten priorities in the country. Potato is a fundamental staple food crop in South Africa, providing essential nutrition. While there are several cultivars currently in production for the potato market, there is a need to explore cultivars that are available, but not utilised within the country. Pigmented potatoes are not regarded as high value on the South African market;however,yield prospects as well as health-promoting benefits could have a positive contribution on the South African Gross Domestic Product (GDP) and on the population’s health. Potato cultivar (cv.) Salad blue(SB)seems to be a drought-tolerant crop with the ability to produce reasonable yields under severe environmental conditions. In order to promote cv. SB as a possible food security option for South Africa, there is a critical need for empirical information, describing some basic horticultural as well as biochemical information and vitamin C presence. This study investigated the potential of pigmented potato SB tubers as an alternative to high yielding white potato for the South African market.Tubers of Solanum tuberosum cv. BP1 and SB, were used for this research.The high amounts in phenolic compounds in SB can be considered to be health-promoting phytochemicals. Anticarcinogenic, antibacterial, antiviral properties have been reported. A greenhouse, bag trial with virus-free plantlets of BP1 and SB cultivars was conducted using three water and nutrient levels and favourable root zone temperature(100% without heat, 100% heated, 50% heated, 25% heated) all grown in coco peat. Cultivar SB showed nearly two-fold yield compared to the control BP1. Methanol extracts of the tubers were assessed for their total polyphenolic, flavanol, and flavonol contents as well as 1-diphenyl-2-picrylhydrazyl (DPPH) scavenging ability, ferric reducing antioxidant power (FRAP), Trolox equivalence antioxidant capacity (TEAC),anthocyanin and L-ascorbic acid assays.The aqueous extract of the SB tubers was found to contain higher level of total polyphenols (320 mg GAE/g), and flavonol (85 mg QE/g) than the extract of the BP1 tubers with values of173 mg GAE/g (total polyphenol), and67 mg QE/g (flavonol). Similarly, the methanol extract of the tuber skins also exhibited higher DPPH (818,86 IC50mg/mL), FRAP (18,19μmol AAE/g), and TEAC (911,12μmol TE/g)than the extract of the BP1with DPPH (595,99 IC50mg/mL), FRAP (10,86 μmol AAE/g) and TEAC (435,44 μmol TE/g). The present study provides useful information for farmers and health professionals in respect to increased yield and health-promoting benefits of an underutilized potato variety.

Development and implementation of modern biotechnological module for year-round virus-free potato (Solanum tuberosum) mini-tuber production

Development and implementation of modern biotechnological module for year-round virus-free potato (Solanum tuberosum) mini-tuber production

In vivo performance of hi-tech planting materials for seed potato production: A review

The production of healthy seed is very crucial to sustain the production and productivity of potato. Traditionally used conventional seed potato production system leads to lower multiplication rate, have bulkiness of seed tubers and encourages accumulation of tuber borne viruses, fungi and bacteria in subsequent seasons leading to significant losses in quality and tuber yield over seasons. Hi-tech seed production systems based on micro-propagation technologies improves the quality of breeder seed, enhance seed multiplication rate and reduce field exposure of seed crop. Under this system, there are three different type of seed production systems viz micropant, microtuber and aeroponic based. The major components of hi-tech seed production include development of healthy mother plants, followed by mass multiplication of healthy mericlones through in vitro micropropagation which is used for microtuber/aeroponic production, minituber production from microtubers/aeroponic tubers or directly from micro-plants under protected conditions (G-0) followed by two field multiplication for production of prebasic and basic seed potatoes. Growth (emergence, plant height, compound leaves and stems) and yield parameters (mean tuber weight and yield by number and weight) varied as per hi-tech planting materials viz microplant, microtuber and aeroponic tuber, crop husbandry, genetic background/cultivar and size of planting materials used for minituber production under in vivo (G-0) in different agro climatic systems.

Comparison of Aeroponics and Conventional Potato Mini Tuber Production Systems at Different Plant Densities

Mini tubers are the starting materials of a disease-free seed potato production scheme. Low multiplication rates as well as non-homogenous tuber size distribution are considered the main constraints of a conventional mini tuber production system. In recent years, an aeroponics production system has been developed to overcome the aforementioned problems. It has previously been observed that this system allows multiple harvests with an average yield of 20–50 mini tubers per plant. Several factors, such as cultivar, planting density, nutrient composition of the mist solution, spraying interval and duration and lighting also affect both tuber number and tuber size. However, less attention has been paid to the association of these factors with the aeroponics system. This paper highlights the importance of planting density effect on conventional and aeroponics system. The mini tuber production performances of three potato cultivars (Hermes, Marabel and Sante) were compared at four different planting densities (25, 50, 100 and 200 plants/m2) under both conventional and aeroponics systems in two production cycles. The number of tubers per plant increased with decreasing planting density, being highest at 25 plants/m2 and lowest at 200 plants/m2 for both cycles. Mean tuber number in the aeroponic system was 19.85 tubers per plant at 25 plants/m2 and 13.20 tubers per plant at 200 plants/m2. As the number of tubers per plant decreased, so did their size. As planting density increased, tuber yield per plant both in aeroponics and conventional system decreased, but in general, tuber yield per plant was higher in aeroponics than in the conventional system. In the 1st cycle, the number of tubers per m2 for Hermes, Sante and Marabel was 290, 364 and 334, respectively, in the conventional system and 787, 1021 and 1168, respectively, in the aeroponics system. Similar numbers were recorded in the 2nd cycle. The average tuber weight was higher in the conventional than in the aeroponics system. Tuber yield/m2 in this study varied from 5.9 to 9.3 kg/m2 in the aeroponics system, about twice as high as in the conventional system.

Standardization of agro-techniques for aeroponic potato (Solanum tuberosum) minitubers under generation-0

Since, very less information is available regarding the agro-techniques of hi-tech seed potato minitubers production, therefore an experiment was conducted to evaluate planting geometry and different doses of nitrogen for multiplication of aeroponic minitubers of potato (Solanum tuberosum L.) under net house conditions of north-central plains of India. 30 cm × 15 cm (97.44) plant geometry and 150 kg N/ha (95.81) and 180 kg N/ha (96.98) N dose recorded significantly higher emergence %. Linear increase in plant height was recorded with 120, 150 and 180 kg N/ha dose over 75 kg N/ ha (44.1 cm). Planting geometry 45 cm × 10 cm (34.71) and N dose 150 kg N (35.71) recorded significantly lowest per cent of <3 g minituber by number. Planting geometry 45 cm × 10 cm (1722 thousand/ha) followed by 30 cm × 10 cm (1587 thousand/ha) recorded significantly highest total tuber number over 30 cm × 15 cm (1209 thousand/ ha). Among N dose, 120 kg N (1560 thousand/ha) and 180 kg N/ha (1506 thousand/ha) dose recorded significantly higher total tuber number over 150 kg N/ha dose. Among interaction 45 cm × 10 cm with 120 kg N/ha dose recorded significantly highest total tuber number (1823 thousand/ha) over other combinations. For weight of tubers, 45 cm ×10 cm planting density with 150 kg N/ha reported highest tuber weight (27.62 t/ha). Hence, for the aeroponic seed multiplication of the variety Kufri Lauvkar, planting geometry of 45 cm × 10 cm with plant population of 222222 plants/ha and N, P2O5 and K2O ratio of 150:60:100 kg/ha should be adopted for getting higher tuber number and weight/ha.

A novel sustainable aeroponic system for healthy seed potato production in India – An update

High yielding varieties and sound planting materials are prerequisites for sound seed potato production. Low multiplication rate, high seed (tuber) rate, dynamic amassing of degenerative infections, perishability and massiveness are the inherent issues in seed potato production. This may result in non-accessibility/non-availability of sufficient amounts of value seeds at reasonable cost and seed cost alone reflects 40% which is half of the aggregate expenses of development in potato. To go around a portion of these issues, a few alterations, for example, tuber ordering for infection opportunity, seed increase stages and seed accreditation guidelines have been created and incorporated with regular potato seed generation programs. The advent of tissue culture, in which virus-free plants can be produced through meristem culture, maintained indefinitely under controlled conditions and multiplied in artificial media under sterile conditions in the laboratory throughout the year irrespective of growing season, has revolutionized seed production in potato world over. Recent developments in automation of minitubers production have further enhanced adaptability of these techniques in potato seed production. In addition to quality assurance through meristem culture, aeroponic technique of minitubers production ensures high multiplication rate at initial stages of quality seed potato production.

Callus Induction and Virus Free Potato Mini-Tuber Production through Meristem Culture

The experiments were conducted with a view to establish a protocol for virus free mini-tubers production, in vitro, using potato meristem as explant, collected from potato sprouts of three popular potato varieties Diamant, Cardinal, Granola. In the present study four levels of GA3 (100, 200, 300 and 400 ppm) were used to assess the influence on sprouting abilities in three selected potato verities. The maximum sprouting efficiency was observed in 400ppm GA3 treatment within short period of time in Granola variety. The effect of different combination and concentration of IBA, 2, 4-D and BAP was used along with fresh MS media to inoculate meristems of potato sprouts. IBA concentration were 0.25mg/L, 1.5mg/L; 2, 4-D concentration were 0.125mg/L, 0.25mg/L, 0.37mg/L, 0.50mg/L, 1.0mg/L 2.0mg/L and BAP concentration were 0.5 mg/L, 1.0 mg/L, 1.5 mg/L and 2mg/L. The effect of combined hormones was also studied. The Diamant variety showed the maximum callus size (0.74cm) within a very short period of time (2 days) while treated at the concentration of 0.25 mg/L IBA, 0.25 mg/L 2, 4-D and 1.00 mg/L BAP. Granola meristem inoculated in hormonal treatment showed the best results regarding minimum days required to shoot initiation (5.34 days) followed by Diamant (6.68) days and Cardinal (7.64 days). The highest number of shoots/plantlet (4.33 shoots/plantlet) and the longest plantlet (9.32 cm) was found in Granola variety followed by Diamond (3.67 shoots/plantlet; 7.53cm) and Cardinal (4.0 shoots/plantlet; 7.62 cm). Maximum numbers of leaves were also found in Granola variety (15 leaves) in the treatment combination of 0.25 mg/L IBA, 0.125 mg/L 2,4-D and 0.5 mg/L BAP. Granola gave maximum performance in respect of maximum length of root (6.55 cm roots/plantlets) within a short time of root initiation (20 days), followed by Diamant (4 cm roots/plantlets) of root initiation (4.47 days) and Cardinal (4.53 cm roots/plantlets) of root initiation (26.39 days). Rooted plantlets were gradually acclimatized and successfully established in the field. However, in overall observation in this study, Granola showed better performance from meristem tissue culture and all plants were found normal and free from potato viruses that were tested through ELISA test.

Challenges in the Production of High-Quality Seed Potatoes (Solanum tuberosum L.) in the Tropics and Subtropics

The potato has been a widely used vegetable crop in temperate countries for a long time. Its consumption and the area of its cultivation has increased significantly over the past decades in the tropics and subtropics as well. The main problems of potato producers in the tropics and subtropics are the unsatisfactory quality of seed potatoes, mainly derived from the informal seed supply system, and the insufficient availability and high cost of certified seed potatoes. The hope for improving this situation can be the application of soil-less technologies for minituber production under controlled conditions. This publication focuses on important advantages of the aeroponic system in the production of pre-basic seed potatoes in the tropics and subtropics. It also highlights some deficiencies that can be overcome with the involvement of several actors in the potato industry, including local universities and the private sector. It emphasizes that innovative aeroponic installations are an opportunity to increase the production of high-quality seed potatoes in the countries of the tropics and subtropics, which, in many cases, will result in less dependence on expensive imported seed potatoes, often from a different climate zone. The introduction of aeroponic installations conserves the shrinking natural soil and water resources and contributes to their protection.

Obtaining high quality potato seed material on aerohydroponic installations

The results of the study on the production of potato minitubers by aeroponic and aero-hydroponic methods, which are non-substrate methods of growing plants, are presented. In order to develop technologies for growing virus-free potato seed material in closed systems, experiments on growing potato minitubers in multiuse aeroponic systems were conducted. Early-ripening potato varieties Rosara, Antonina and Yubilyar, mid-ripening Solnechny variety, and S-112 and Ch hybrids were used as the tested potato varieties. The plant growing cycle was divided into three phases: adaptation, growth, and tuberization. For each phase, different cultivation parameters were used. As a light source, highpressure sodium lamps DNaT 400 were used. The quantitative yield of potato minitubers per one plant on this type of systems was as follows: Antonina variety – 15.3 pcs., Yubilyar variety – 23 pcs., Hybrid Ch – 28.1 pcs., Hybrid S-112 – 30.2 pcs., Solnechny variety – 30.3 pcs., Rosara variety – 43.9 pcs. The effect of various light sources on the quantitative yield of potato minitubers of Nevsky and Yubilyar varieties was studied for this type of systems. Cultivation of potatoes in these systems was carried out according to the technology described, but using two different types of light sources. In the control variant, high-pressure sodium lamps DNaT 400 were used, in the experimental variant, LED lamps produced by CoB (full spectrum) technology with a passive cooling system were used. The use of LED lighting on Nevsky variety led to a statistically signifi cant increase in the quantitative yield of potato minitubers from one plant compared to the control, by 20.88%. The prospects of using Fagro aero-hydroponic systems for adaptation of potato microplants and for obtaining potato minitubers of Rosara and Solnechny varieties were shown. The quantitative yield of potato minitubers per plant on this type of installations was 46.9 pcs. for Rosara variety, and 56.7 pcs. for Solnechny.

Yield of Potato Minitubers under Aeroponics, Optimized for Nozzle Type and Spray Direction

Potato seed production by conventional methods represents a sizeable investment that, when passed on to farmers, can decrease their profit margins. Potato minitubers produced by aeroponic systems are space- and cost-efficient, and they also provide healthy propagules to be used by farmers. We evaluated the effects of different misting nozzle types, with and without an antidrip feature, and spray direction on potato minituber yield using the Federal University of Viçosa (UFV) Aeroponic System. Potato plants (cv. Agata) propagated from sprouts were grown in a covered, high-density 100-L polyethylene bucket. The experiment was set up in a randomized complete block design with four replicates and eight treatments combining misting nozzle types (Fogger, MA-30, and CoolNet) with and without antidrip and comparing upward with downward spray directions. Plants were evaluated weekly from 33 to 68 days after transplant (DAT). The parameters used to evaluate treatments were number and mass of minitubers as a function of harvest times, dry mass of roots, stems, leaves, and total biomass. The number and fresh weight of minitubers, as well as root dry weight, stems, leaves, and total biomass were affected by misting nozzle types and spray direction. Treatments also affected biomass partitioning of roots, stem biomass, and the shoot:root ratio. There was also an effect of harvest time on the number and fresh weight of minitubers for various combinations of misting nozzle type and spray direction, except for minituber number with the CoolNet misting nozzle without antidrip and downward spray direction. On the basis of the assessed parameters, the best minituber production system was achieved with the Fogger spray combined with no antidrip, a rate of 12 L·h−1, and with the downward spray direction. The UFV Aeroponic System produced an average of 491 minitubers per plant. This system is simple to implement and may lead to a more affordable upscaling of potato seed minituber production.

Effects of different LEDs light spectrum on the growth, leaf anatomy, and chloroplast ultrastructure of potato plantlets in vitro and minituber production after transplanting in the greenhouse

Light spectrum plays an important role in regulating the growth and development of in vitro cultured potato (Solanum tuberosum L.) plantlets. The status of potato plantlets at the end of in vitro stage influences the minituber production after transplanting. With 100 µmol m−2 s−1 total photosynthetic photon flux density (PPFD), a light spectrum study of 100% red light emitting diodes (LEDs) light spectrum (RR), 100% blue LEDs light spectrum (BB), 65% red+35% blue LEDs light spectrum (RB), and 45% red+35% blue+20% green LEDs light spectrum (RBG) providing illumination at the in vitro cultured stage of potato plantlets for 4 weeks using fluorescent lamp as control (CK) was performed to investigate the effects of LEDs light spectrum on the growth, leaf anatomy, and chloroplast ultrastructure of potato plantlets in vitro as well as the minituber yield after 2 months transplanting in the greenhouse. Compared to CK, RB and RBG promoted the growth of potato plantlets in vitro with increased stem diameter, plantlet fresh weight, plantlet dry weight, and health index. Furthermore, BB induced the greatest stem diameter as well as the highest health index in potato plantlets in vitro. Root activity, soluble protein, and free amino acid were also significantly enhanced by BB, whereas carbohydrates were improved by RR. In addition, thickness of leaf, palisade parenchyma and spongy parenchyma was significantly increased by BB and RBG. Chloroplasts under BB and RBG showed well-developed grana thylakoid and stroma thylakoid. Unexpectedly, distinct upper epidermis with greatest thickness was induced and palisade parenchyma and spongy parenchyma were arranged neatly in RR. After transplanting in the greenhouse for 2 months, potato plantlets in vitro from BB, RB, and RBG produced high percentage of large size tuber. BB improved fresh and dry weights of the biggest tuber but decreased tuber number per plantlet. In addition, RBG increased tuber number as well as tuber fresh and dry weight slightly. Our results suggested monochromatic blue LEDs as well as combined red, blue or/and green LEDs light spectrum were superior to fluorescent lamp spectrum in micropropagation of potato plantlets. Therefore, the application of RBG was suitable; BB and RB could be used as alternatives.

Evaluation of Economically Important Cultivars of Seed Potato for Minituber Production

Experiments were conducted to evaluate mass production of potato minitubers by using in vitro produced plants and sprout cuttings under Gilgit Baltistan conditions. The experiments were arranged in Complete Randomized Design and replicated three times. Four potato cultivars ‘Roko’, ‘Bartina’, ‘Barna’ and ‘Kuroda’ multiplied in vitro through nodal cuttings were planted in a greenhouse. The cultivars showed variation in different parameters studied. Results revealed that cv. ‘Kuroda’ showed greater plant height (103.7 cm), higher total tuber weight per plant (194 g) and the maximum number of minitubers per plant (21.9) as well as total number of minitubers per plot (14,235) from 650 in vitro produced plants, whereas shorter plant height (33.4 cm), lower tuber weight per plant (102.8 g) and the minimum number of minitubers per plant (9.4) and total number of minitubers per plot (6,110) were observed in cv. ‘Bartina’. However, the cultivar Bartina’ produced the maximum number of stems per plant (2.2), while cv. ‘Roko’ had the minimum number of stems per plant (1.4). In another experiment, the cultivars ‘Roko’, ‘Asterix’, ‘Barna’ and ‘Paramount’ were reproduced using sprout cuttings (650 each) grown under screen house conditions. The cultivar ‘Asterix’ developed maximum number of minitubers per plant (5.9) and per plot (3,835 g). However, plant height was greater (93.4 cm) in cv. ‘Paramount’ and total tuber weight per plant was higher (198.3 g) in cv, ‘Barna’. On the other hand, the short plant height (52.2 cm) and lower total tuber weight per plot (144.7 g) were produced in cv. ‘Roko’, and the minimum number of minitubers per plant (4.7) and total minitubers per plot (3,055 g) were observed in variety ‘Barna’. The performance of in vitro produced plants of cv. ‘Kuroda’ was better under greenhouse conditions; while plants of cv. ‘Asterix’ produced through sprout cuttings performed better under screen house conditions.