Number Of Minitubers Research Articles

Essential Quality Attributes of Culture Media Used as Substrates in the Sustainable Production of Pre-Basic Potato Seeds

The sustainability of the primary sector is closely linked to meeting the demand for seeds using agro-industrial waste and bioresidues. Sustainability is a multidimensional concept focused on achieving environmental health, social justice, and economic viability. To this end, an experiment was designed based on a combination of biotechnological strategies accessible to many individuals. The first strategy involves the use of compost and vermicompost as cultivation substrates; the second is the in vitro acclimatization of potato plants to these substrates; and the third is the incorporation of Trichoderma asperellum into these substrates to determine the synergistic effect of both. The compost used in this work came from sewage sludge from an agri-food company (Cp); a dining room and pruning waste from a university campus (Cu); and vermicomposted coffee pulp waste (Cv). Each sample was mixed with coconut fiber (Fc) in proportions of 100, 75, 50, and 25%. In the resulting mixtures, María Bonita variety vitroplants were planted and placed in a greenhouse. The biometric response in the three cases indicated a dependence on the type of compost and the proportion of the coconut fiber mixture. The inoculation of Trichoderma asperellum with sewage sludge compost increased stem thickness (42.58%) and mini-tuber weight (6.74%). In contrast, uninoculated treatments showed the best performance in terms of the number of mini-tubers. A 50:50 mixture of sewage sludge compost with coconut fiber and without inoculation of Trichoderma asperellum was the best treatment for the production of pre-basic seeds of the María Bonita potato variety. The use of composted agricultural waste and bioresidues is shown as a valid and low-cost alternative for the sector, even independently of the incorporation of additional inoculants.

Mycorrhizae enhance minituber weight and nutrient content in potatoes transferred from in vitro to hydroponic culture under different phosphorus levels

The survival and productivity of potato plantlets transplanted from in vitro to commercial hydroponic minituber culture are crucial. Mycorrhizal fungi are an efficient tool to enhance potato nutrient uptake, survival, and productivity under these conditions. This study aimed to assess the effect of mycorrhizal fungi on improving the yield of minitubers and nutrient uptake in potatoes transferred from the in vitro environment to the greenhouse. This study was conducted in a greenhouse in Hamadan province, I.R. Iran, in 2013. The experimental design was factorial, including treatments with and without inoculation with the mycorrhizal fungus Rhizophagus irregularis and varying phosphorus (P) concentrations in Hoagland’s solution (100%, 75%, 50%, and 25% of its maximum content, i.e. 0.965, 0.482, 0.241, and 0.12 mM H2PO4 -) with three replications on potato plantlets transferred from in vitro to pots. The results indicated that the highest colonization percentage was achieved with 25% P and inoculation. The highest number of minitubers (8.9), total minituber weight per plant (53.2 grams), plant height (54.6 cm), minituber (0.38%) and leaf (0.363%) P content, minituber (33 mg/kg) and leaf (65 mg/kg) manganese (Mn) content, and minituber (38 mg/kg) and leaf (65 mg/kg) zinc (Zn) content were obtained with inoculation and 75% P of Hoagland nutrient solution, which was statistically comparable to the inoculation with 100% P treatment. In summary, inoculating potato plantlets with mycorrhiza can enhance minituber yield and nutrient uptake and potentially replace approximately 50% of the P requirement in hydroponic solutions.

Best Morpho-Physiological Parameters to Characterize Seed-Potato Plant Growth under Aeroponics: A Pilot Study

Best Morpho-Physiological Parameters to Characterize Seed-Potato Plant Growth under Aeroponics: A Pilot Study

Effect of various concentrations of agar and sucrose on growth and tuberization of four Potato (Solanum tuberosum L.) varieties under in vitro, invivo conditions

The study tends to evaluate the effect of different concentrations of agar treatment (5, 7, and 9 g.l-1) with sucrose (20, 30, and 40 g.l-1) on in vitro shoot regeneration and rooting in one step using tuber-eyes and node explants of four potatoes (Solanum tuberosum L) varieties “Sagitta, Challenger, SM 13–132– 05 and Taurus”, and minitubers production under greenhouses conditions which are going to be grown in Kurdistan -Iraq. The results showed that SM 13–132– 05 cultivar was superior upon the other cultivars under in vitro conditions through multiplication tests (Agar concentration 7 g.l-1 and sucrose concentration 30 g.l-1) and greenhouse conditions by producing the highest shoot multiplication (3.17 shoots/ explant, 12.84 leaves/ explant and 14.51cm mean length of roots) and the best number of minitubers (5.72 minitubers/ plantlet) in greenhouse. Whereas, Challenger had the lowest number of minitubers (3.75/ plantlet). On the other hand, there was no significant differences in the effect of the different concentrations of Agar and sucrose on the four cultivars in terms of the rooting percentage.

Physiological and biochemical features of implementation of the adaptive potential of clonally micropropagated potato plants using immunostimulants

The effect of epibrassinolide in combination with salicylic acid and methyl jasmonate on the formation of complex resistance of clonally micropropagated potato plants of the Briz variety to the potato virus Y and to moisture lack, their physiological state, the functioning of the pro-/antioxidant system, as well as on the productivity and quality of the obtained mini-tubers was studied. It was revealed that antiviral resistance under combined stress conditions is formed only in the presence of epibrassinolide that triggers a series of protective mechanisms through accumulation of hydrogen peroxide, phenolic compounds and an increase in peroxidase activity, while maintaining productivity and improving the quality of the products obtained. The use of a three-component mixture is accompanied by the largest mass and a number of potato minitubers, while its protective effect against a viral infection is not manifested.

Obtaining mini-tubers of potato varieties at in vitro laboratory research conditions in Zarafshan Valley

The article presents data from in vitro laboratory research conditions on the growth-supporting of mini-tubers on various nutrient environment. It was found that with the composition of the nutrient medium including sucrose in the amount of 90 mg/l and gibberillin 1.5 mg/l, kinetin 1.0 mg/l, IUK - 2.0-2.5 mg/l, the variant had high growth and development of the plant, the mass of stems and leaves was at the level of 8.4 grams, the number of mini tubers was 12.9 pcs., with an average weight of 8.8 grams, and in one container they harvested 14.0 units of mini–tubers, 154.0 units per 1 m2, 462.0 units on 3-storey racks (in 2 months), and in one year they received 2772 pieces of high-quality seed mini-tubers. When planting mini tubers in a phytotron according to the 70x20 cm scheme, the height of the plant is 60.0-70.0 cm, the number of stems is 1.9-2.1 pieces, the number of tubers in one bush is 8.0-9.1 pieces, their average weight per bush is 55.0-64.5 grams, with an average yield in one bush of 451.0-586.0 grams, it turns out 32.2-41.8 t/ha.

Usage of different planting schemes for mini-tubers potato growing under North Ossetia-Alania republic conditions

The purpose of the research is to study the effect of different planting schemes of the base lines on the quantitative yield of mini-tubers in the conditions of Republic of North Ossetia-Alania. The object of the research was microplants and microtubers of new promising potato varieties Gulliver, Sadon and Varyag. The experiments were carried out in 2020-2022, laid on a peat substrate using planting patterns 25x25 cm in plastic pots, 25x30 and 25x15 cm in the ground. Growing mini-tubers according to the scheme 25x25 cm in pots contributed to the formation of from 139.4 to 155.5 pcs/m2 with a standard seed fraction yield of 88-94%. An increase in the nutrition area as a result of planting the base lines into the soil according to the 25x30 cm scheme reduced the number of formed mini-tubers by 19.4-49,0 pcs/m2 with a standard yield of 77-85%. According to the 25x15 cm scheme, the total yield of mini-tubers increased by 19-35 pieces/m2, but the yield of the standard fraction decreased to 57-74%. In the original seed production of potatoes, an important indicator in the cultivation of mini-tubers is the yield of a fraction of more than 20 mm in transverse diameter. The maximum yield of mini-tubers with such dimensional characteristics was noted when planting micro-plants according to the scheme 25x25 cm - 113.7 pcs/m2. The use of micro-tubers according to this scheme reduced the number of mini-tubers with a fraction of more than 20 mm to 91.7 pcs/m2 or by 19%. As a result of applying the schemes of 25x30 and 25x15 cm, the quantitative yield of mini-tubers with a fraction of more than 20 mm did not depend on the origin of the base lines and amounted to 58.5-65.6 pcs/m2. Based on the studied planting schemes in protected ground in the Republic of North Ossetia-Alania, the maximum yield of mini-tubers with the best dimensional characteristics was obtained as a result of planting the base lines according to the 25x25 cm scheme in plastic pots. Reducing the feeding area according to the 25x15 cm scheme reduced the yield of mini-tubers of a fraction of more than 20 mm by 1.8-1.9 times.

Effect of nutrient solution concentrations on the growth and yield of potato (Solanum tuberosum L.) varieties grown from apical rooted cutting in a hydroponic system

This study evaluated the effects of nutrient stock solution concentrations on the growth and yield of potato varieties grown from apical rooted cuttings (ARCs). A greenhouse experiment was conducted at the Climate and Water Smart Agriculture Center at Egerton University, Kenya. The experiment was laid out in a split-plot arrangement in randomized complete block design, where the main plot comprised three nutrient concentrations, i.e., 75% (N75), 100% (N100) and 125% (N125) of the ADC-Molo’ nutrient formulation. The subplots were allocated to four potato varieties (Shangi, Wanjiku, Nyota and Unica). The results showed that there were no significant (p<0.05) interaction effects of the nutrient stock solution concentrations application rates on the growth attributes of ARCs. The main effects of N125 gave the tallest plants (32.29cm) at 60 days after planting (DAP), highest normalised difference vegetation index (NDVI) (0.60) at 75 DAP, plant survival rate (82.15%) at 75 DAP, and fresh weight (79.04g) and dry matter (31.26%) of aboveground biomass (AGB). Nyota variety produced taller plants (26.90cm) at 60 DAP, gave higher NDVI values (0.53) at 75 DAP, and higher fresh weight (64.87g) and dry matter (27.60%) of the AGB. Significant (p<0.05) interactions were observed in the yield parameters. The interaction between N125 and Nyota (11.33) and Wanjiku (10.67) gave the highest number of minitubers, the highest yields were obtained between the interaction of N125 and Unica (16.38t/ha). Therefore, to achieve high growth and yields of ARCs under hydroponic system, seed potato producers should use 125% of the ADC Molo nutrient formulation.

Development of technology for obtaining healthy seed material of potato variety Charoit

The effect of nutrient media of different composition on the growth and development of healthy potato microplants of the Charoit variety under in vitro conditions was studied. Three variants of nutrient medium compositions were considered: nutrient medium according to Murashige-Skoog prescription, Murashige-Skoog medium with a reduced content of mineral components to 1/2 and to 1/3. The following microplant parameters were studied: height, rhizogenesis, number of leaves and internodes, total plant weight, leaf weight, root weight, stem weight, shoot weight. On a nutrient medium with 1/2 mineral components, the height of potato microgrowers on the 28th day of cultivation increased by 12%, the shoot weight - by 17% by increasing the weight of leaves by 33% and the weight of the root system twofold, the total plant biomass - by 28%. When using a nutrient medium with 1/3 of mineral components for cultivation of healthy potato varieties Charoit microplants on the 28th day of cultivation, a decrease in the shoot weight by 17% was observed due to a decrease in the stem weight (25%), and the weight of the root system increased by 140%. In these variants of nutrient medium, rhizogenesis began earlier and proceeded more actively than in the control. A medium with 1/2 content of mineral components of the norm was determined to be optimal for growing microplants in vitro. When aerohydroponic plants were grown with different plant densities (21, 27, and 55 plants/m ), a 27% increase in the plant height of the plants grown on plant sections with a planting density of 55 plants/m2 was observed. The plants with a planting density of 21 plants/m2 differed from the other variants by an increased number of stems. In the minituber yield, the proportion of fractions suitable for further seed production was more than 50% when using all planting densities studied on aerohydroponic plants. The maximum number of minitubers was recorded when growing plants with a planting density of 55 plants/m2, and this option is recommended for use in the cultivation of minitubers of the potato variety Charoit by aerohydroponic method.

Effect of planting periods on production potential of potato (Solanum tuberosum) varieties under aeroponics

An experiment was conducted during 2017–18 in the aeroponic unit of ICAR-Central Potato Research Institute inShimla, Himachal Pradesh, to evaluate 3 potato (Solanum tuberosum L.) cultivar’s, viz. Kufri Mohan, Kufri Lauvkarand Kufri Himalini growth and production behaviour under 2 different planting periods spaced 10 days apart duringthe autumnal season. The yield per plant and the total number of mini-tubers were shown to be strongly impactedby the planting season as well as the cultivar, according to the findings. The average number of tubers harvested was 32.7/plant in early (10th September) planting as against 21.2 mini-tubers/plant in late (20th September). Similarly, yield per plant was significantly higher (67.67 g/plant) with early planting than with late planting (35.99 g/plant). The production behaviour of the potato varieties under consideration varied significantly. The maximum yield/plant and mini-tuber numbers were recorded in Kufri Lauvkar (34.17 and 73.12 g/plant, respectively), which were significantly higher than the remaining 2 cultivars, which were statistically at par for both the number of yield/plant and minitubers. A delay in the planting of 10 days under aeroponics results in a significant reduction not only in the vigour of plants but subsequently in the number as well as weight of mini-tubers harvested. Thus, for attaining higher rates of multiplication under aeroponics during the autumn season, planting should not be delayed beyond 10th September in a hilly temperate wet zone.

Determination of optimum planting density of very small potato minitubers and appropriate pot size for maximizing seed tuber production in screenhouse conditions

AbstractTissue culture, aeroponics, and hydroponics have improved the production of first‐generation potato (Solanum tuberosum L.) minitubers in Ethiopia. However, some minitubers may be very small (<5 g) and would probably fail to survive in open‐field conditions. Thus, they are usually replanted in screenhouses in pots as single tubers/hills. The impact of pot size and number of minitubers that can be feasibly planted per pot to obtain optimal yield with little impact on progeny tuber size require investigation to optimize indoor seed potato production. Consequently, a screenhouse experiment was conducted at Adet Agricultural Research Center, Amhara, Ethiopia, between 2020 and 2021 to investigate the effect of seed density and different pot sizes on a number of tubers harvested per pot, per planted minituber, and average tuber weight (g). Experimental treatment factors were potato variety at two levels, pot size at three levels, and seed density at five levels. Five replications per treatment combination, each with four pots, were used. Analysis of variance, with seed density up to cubic component as single‐degree polynomial contrast, showed that the assessed variables were not significantly (P ≤ 0.05) affected by potato variety. All two‐ and three‐way factor interactions except pot size by seed density for the number of tubers harvested per planted minituber were not significant (P ≤ 0.05). Pot size significantly (P ≤ 0.05) affected the number of tubers harvested per pot and per planted minituber but not the average tuber weight. All the assessed variables were significantly (P ≤ 0.05) affected by seed density. The number of tubers harvested per pot increased significantly (P ≤ 0.05) with increasing pot size and seed density. Polynomial regression showed that linear and quadratic components of seed density as a predictor of the assessed variables were significant (P ≤ 0.05); however, its polynomial components did not significantly (P ≤ 0.05) interact with main treatment factors. The estimated optimum seed density from the derivatives of the polynomial functions was five tubers per pot. The predicted minimum average tuber weight was 18.5 g, which is appreciably high for good open‐field minituber survival. Meanwhile, the 10‐L pot produced significantly (P ≤ 0.05) more minitubers than other pot sizes; however, it had the lowest production efficiency per unit area of screenhouse and per kilogram of culture substrate. Thus, 2‐ and 6‐L pots, each planted with five minitubers, irrespective of the potato variety are recommended to maximize productivity of minitubers and screenhouse space with little or no impact on progeny tuber size.

Increasing Potato Sustainability to PVY under Water Deficiency by Bacillus Bacteria with Salicylic Acid and Methyl Jasmonate

The protective effect of Bacillus bacteria against viruses can be significantly expanded by combination with salicylic acid (SA) or methyl jasmonate (MeJ). In soil water deficiency conditions, potato leaves were sprayed with Bacillus subtilis strain 47 combined with MeJ and MeJ + SA displayed a decrease in PVY and preservation of the shoot’s growth. Signaling molecules with Bacillus subtilis mitigated the adverse effect of PVY under water deficiency by manipulating enzymatic/non-enzymatic antioxidant levels and activity in treated plants. The application mixtures increased the mass and number of mini-tubers during the microclonal propagation of plants. Treatment with bacteria in combination with signaling molecules significantly changed the content and phosphorylation status of a number of hydrolases, catalase, phosphorylase, annexin, and protease inhibitor. Based on the analysis of changes in the proteome, the key mechanisms mediating the induction of plant resistance to change in the tuber proteome aimed at enhancing the expression of protective protein genes that increase resistance to pathogens and abiotic stress.

Mycorrhization of Xanthosoma sagittifolium L. Schott Plants (White Cultivar): Evaluation of Their Effect on Acid Phosphatase Activity During Growth and Production of Minitubers

This work's main objective was to evaluate the effect of certain strains of arbuscular mycorrhizal fungi on acid phosphatase activity during growth. The treatments applied were, control, Glomus intraradices, Acaulospora tuberculata, Gigaspora margarita, Glomus sp., and the mixture of these four AMF strains. Their effect on the growth of vitroplants was evaluated on days 60, 120, and 180 after inoculation. Mycorrhizal status following treatments and acid phosphatase activity were assessed. The minitubers obtained were subjected to a preservation and germination test. The results showed that the maximum growth peak of X. sagittifolium plants was obtained on day 120 for all treatments. The mixture of the four strains of AMF had more influence on the growth parameters with values of 18.40±0.54 Cm and 42.34±16.67 Cm2, respectively for the average number of roots and leaf area. Mycorrhization did not significantly influence the mean number of leaves and mean plant height. Mycorrhizal structures were observed in all mycorrhizal treatments applied. The frequency of mycorrhization was very high in plants inoculated with Glomus sp. The evaluation of the phosphatase activity shows a significant activity at the level of the leaves with a peak of activity in the plants inoculated with Glomus sp. (47.72±0.07 µM/min/g of FW). Compared to the control, the number of minitubers produced was two to three times higher. The best tuberization percentage (80%) was obtained in plants inoculated with a mixture of AMF strains. The temperature of 7~10°C allowed the preservation of 50% of the germination capacity of the minitubers after two months. Based on the obtained results, it was concluded that fertilization with AMF is beneficial for the stimulation of minitubers production.

Produção de minitubérculos de inhame para propagação vegetativa alternativa: tipo de estacas, substratos e anatomia

ABSTRACT: Yam is a tuber vegetable crop with vegetative propagation. The crop is low yielding due to the difficulty of obtaining quality material for propagation and the high cost of acquisition. The cutting technique is a new alternative for vegetative propagation of yam. The present studyevaluated the production of minitubers of yam through cuttings, and follow the formational growth of the minitubers. Different types of cuttings, obtained from three positions on the shoots, and three substrates were tested. The types of cuttings and substrates did not significantly affect the number of minitubers per cutting, this number ranging from 1.18 to 1.75. The best results were obtained using Tropstrato Florestal® and median-position cuttings for the following variables: minituber length (17.47 mm), minituber diameter (12.63 mm), minituber fresh weight (2.12 g), and percentage of cuttings with two minitubers (75%). Anatomical analysis showed cell divisions and starch accumulation in the nodal region at seven days after planting the cutting. Emergence of the minituber could be observed at 21 days. The production of yam minitubers through stem cuttings is enhanced using cuttings obtained from the median position of the shoot and using the commercial substrate Tropstrato Florestal®.

Introduction of Nutrient Solution of Silicon Sulfonated With Elemental Sulfur S8 for the Mini-tuber Production of Potato Cultivars from in vitro Micro-tuber

This study with aims to investigate the effect of nutrient solution sulfonated silicon with elemental sulfur S8 in the mini-tuber production of potato cultivars in the greenhouse of Potato Research Station of Ardabil Province, Iran was done during April till August of 2022. This experiment was carried out based on the factorial experimental design in two factors and three repetitions. The first factor with two levels including: 1. foliar spraying with nutrient solution sulfonated silicon with elemental sulfur S8 and 2. Control (without nutrient solution sulfonated silicon with elemental sulfur S8) and the second factor consists of micro-tubers of five cultivars in the name of Agria, Jelli, Anosha, T297 and Sheida. The foliar spraying with S-8 nutrient solution was done in five stages of vegetative growth, plant growth and development, tuberization, flowering and tuber development and tuber bulking. The results of analysis of variance showed that there was a significant difference between the levels of nutrient solution, cultivars and the interaction between nutrient solution and cultivars in terms of mini-tuber number and weight per square meter, mini-tuber number per plant and plant height. Anosha cultivar had the highest values in terms of mini-tuber number and weight per square meter and tuber number per plant traits by using nutrient solution and was placed in the group A. The Agria, Jelli, Sheida and T297 cultivars were placed in the group B and had the highest amount by using nutrient solution in terms of these characteristics. The Agria, Jelli and Anosh cultivars had the highest plant height by using nutrient solution. Based on the results, using sulfonated silicon nutrient solution with elemental sulfur S8 causing an increase mini-tuber number per square meter (515 numbers), mini-tuber number per plant (5 numbers), mini-tuber weight per square meter (47 kg) and plant height (92 cm) became.

Effect of growth regulators on the morphological traits of three potato cultivars in vitro

The experiments were conducted to study the effect of sub cultures (3 sub-cultures) of in vitro propagated plants of three cultivars of potato (Arnova, Riviera and Provento) and their interaction with Indole Acetic acid (IAA) at 0.0 , 1.0 mg L-1 and Benzyl Adenine ( BA) at 0.0, 0.5, 1.0 and 2.0 mg L-1 concentrations on morphological traits of vegetative (plant height, number of shoots, leaves , nodes and length of shoots) and roots (number of roots and their lengths) system. The cultures were incubated under temperature of 25 ± 2°C and illumination for 16 h day-1. The plants were transferred to the greenhouse and data were taken on the number of minitubers, their diameter and weight after 90 days. The results showed the effectiveness of IAA at 1 mg L-1 increasing in plant height (16.06 and 14.83 cm for Rivera and Provento cultivars, respectively), and in number of leaves and nodes (18.08 leaf plant-1 for Rivera and 16.92 nod plant -1 for Provento), and the number of roots and their length. (11.25 root plant-1 and 11.25 cm for Rivera and Arnova cultivar, respectively). The results also showed the effectiveness of the combination of IAA (1 mg L-1 ) + BA (0.5 mg L-1 ) increasing the number and length of shoots (6.50 shoot plant-1 and 4.83 cm for Provento and Rivera cultivar). A decrease in the number of roots was also observed with increasing concentrations of BA which added to the medium with or without of IAA. Results also recorded the highest average of diameter and weight of minitubers was 8.63 cm and 3.64 g for the mother plants of the Riviera and Provento cultivars, respectively, while the mother plants and in vitro propagated plants of three cultivars did not differ in the average number of minitubers.

MINITUBERS PRODUCTION OF FOUR POTATO (SOLANUM TUBEROSUM L.) CULTIVARS BY TISSUE CULTURE TECHNIQUE

This study was aimed to produce potato minitubers via tissue culture technique by testing four cultivars; Agria, Nicola, SM 12-124-15 and JIP 1600-1 under in vitro, greenhouse and open-air field conditions. Nicola cultivar was superior upon the other cultivars under in vitro and greenhouse conditions by producing the best shoot multiplication (1.89 shoots/ explant and 13..27 leaves/ explant) and the highest number of minitubers (8.87 minitubers/ plant) in greenhouse whereas, SM 12-124-15 was better in the open field conditions by producing 11.25 tubers per plant, recording the highest mean weight of tubers (321.33 g), the highest weight of tubers per plant (3.615 kg), the bigger sizes of tubers (length 8.22 cm: width 3.43 cm) and the highest total yield per hectare (49.70 Ton/ ha). An interesting microtubers formation was noticed on SM 12-124-15 explants grown on MS medium supplemented with 0.5 mg/l-1 BA. The main conclusion drown from the current study is MS medium with basic vitamins and solidified by agar without the need of adding exogenous plant growth regulators can be used for mass seed tubers production based on potato genotype in vitro under optimized culture conditions with a low cost propagation system and shorter period of time than normal minitubers production process.

Potato Aeroponics: Effects of Cultivar and Plant Origin on Minituber Production

Aeroponics is a modern and soilless technology that is used for the efficient production of pre-basic seed potatoes, namely minitubers. This study aimed to evaluate the effects of the cultivar and type of planting material on the production of minitubers in the aeroponic facility in Guča, Serbia, at short, 7-day harvest intervals. Although aeroponic cultivation prolonged the vegetative cycle in all five investigated cultivars, the dynamics of minituber formation varied between genotypes. Two early maturing cultivars, Cleopatra and Sinora, quickly completed the vegetative cycle and formed a small number of minitubers, while the medium-late to late cultivars, Kennebec and Agria, steadily tuberized during the entire cultivation period in the aeroponic facility. The type of planting material affected the dynamics of minituber formation in three investigated cultivars. Sinora, Cleopatra, and Désirée’s plants of in vitro origin reached the final number of minitubers and the vines started senescing much earlier than plants of minituber origin. Kennebec and Agria plants of in vitro origin produced the largest number of minitubers (53.8–54.5) and showed the highest yield (9.8–10.5 kg m−2) during the cultivation period, while the heaviest minitubers were formed by Sinora plants of minituber origin (15.48 g). In addition, the temperature during pre-harvest periods significantly affected the number of tubers at harvests in Kennebec and Agria, and minituber mass in Désirée.

Shoot and root zone temperatures are critical in bidirectional regulation of tuberization in potato

Multiple signals regulate tuberization in potato and among them, photoperiod and temperature are most crucial. Optimum temperature for tuberization is around 20 °C and elevated temperatures above optimum drastically reduces tuberization. Our study therefore aims at understanding and establishing a system to study the effect of shoot and root zone temperatures on tuberization. Towards this, a less photosensitive cultivar, Kufri Jyoti was identified initially by analysing the allelic variations in CDF1 gene. Using the aeroponic systems housed inside the poly house, the effect of temperature on tuberization was studied. Following staggered sowing on aeroponic chambers during rabi season (Oct-Dec), the shoot zone (Sz) and root zone (Rz) were exposed to elevated mean cumulative day temperatures with one set of chambers regulated to maintain optimum temperature of 19 ± 2 °C in Rz (Rz-R) irrespective of date of sowing/ planting. With delayed planting, plants were exposed to high temperatures and our study demonstrated that, elevated temperatures in Sz and/or Rz had significant effect on growth attributes, tuber number and tuber weight per plant. While the tuber number was significantly higher under optimum root and shoot zone temperature, it was rather decreased by 3.5 and 2.3 for every degree rise in Rz (irrespective of Sz) and Sz (irrespective of Rz) temperature, respectively. However, regulating the Rz temperature inside the aeroponic chambers, reasonably a good number of mini-tubers per plant was produced regardless of the shoot zone temperatures suggesting that, root temperature is more crucial than shoot temperature. Furthermore, reduction in tuberization at elevated temperature was correlated well with reduction in expression of key positive regulators (StSP6A, StBEL5) and enhanced expression of key negative regulator, StSP5G in both leaves and solons. Taken together, our data suggest that, regulation of both root and shoot zone temperatures are important for effective tuberization and tuber yield in potato. • Elevated shoot zone (Sz) and root zone (Rz) temperature above optimum significantly affected plants growth and tuber yield. • Every degree rise in Sz and Rz zone temperature above optimum resulted in significant reduction in tuber number and weight. • Root zone temperature is more critical in regulating tuber number and tuber weight than shoot zone temperature. • At elevated Sz and Rz temperatures, expression of positive and negative regulators decreased and increased respectively. • Regulating Rz temperature would likely to help maintain mini-tuber production even under non-optimal shoot zone conditions.

Improving the efficacy of potato clonal micropropagation by inoculation with the rhizosphere bacteria Azospirillum baldaniorum Sp245 and Ochrobactrum cytisi IPA7.2.

Sustainable development of agriculture depends on the provision of quality seeds to the market. Inoculation with plant-growth-promoting rhizobacteria in in vitro culture can be used to improve the growth eff icacy and performance of microplants. We examined the effect of in vitro inoculation of microplants of the cultivars Nevsky and Kondor with the strains Azospirillum baldaniorum Sp245 and Ochrobactrum cytisi IPA7.2 separately and in combination. We examined the morphological variables of plant growth in in vitro culture and under ex vitro adaptation conditions; we also investigated the growth and performance of the plants in the greenhouse. The dependence of the inoculation eff icacy on potato genotype, growth stage, and inoculum composition was ascertained throughout the experiment. In vitro, A. baldaniorum Sp245 alone and in combination with O. cytisi IPA7.2 promoted the formation of roots on the microplants of both cultivars and the growth of Nevsky shoots. During plant growth ex vitro, all growth variables of the Nevsky microplants were promoted by O. cytisi IPA7.2 alone and in combination with A. baldaniorum Sp245. In both cultivars grown in the greenhouse, shoot growth was promoted in most inoculation treatments. The survival ability of the Nevsky microplants in the greenhouse increased 1.7-fold under the effect of simultaneous inoculation. Inoculation of microplants with a combination of A. baldaniorum Sp245 and O. cytisi IPA7.2 increased the number of Nevsky minitubers 1.5-fold and the number of Kondor minitubers 3.5-fold. Inoculation with the tested strains can be used to promote the growth of microplants and increase the yield of minitubers in potato seed breeding for the production of healthy planting material.