Large Tubers Research Articles

Sustaining Frafra Potato (Solenostemon rotundifolius Poir.) in the Food Chain; Current Opportunities in Ghana

Frafra potato (Solenostemon rotundifolius Poir.)is one underutilized crop species which is critical to improving food security in the Upper East and Upper West Regions of Ghana. Food dishes of Frafra potato (FP) are a delicacy particularly for children. The tubers have high marketing potential even compared with its counterpart, sweet potato. However, crop improvement programmes in FP have been slow leading to the current varieties being recycled for several decades. Research tools such asfield survey, focused group discussions and key informant interviews were employed to gather information on production practices, challenges and strategies to improve FP production and utilization. Information was generated from 10 focused group discussions and 270 respondents in 5 districts. Overall, FP is produced under rain-fed agriculture by less than 30% farmers on less than ¼hectare/farmer. In Bongo, Kongo and Bolgatanga environs, FP is cultivated by over 70% of households to supplement household food. Production is primarily planned for domestic consumption; contributing up to 20% of household food between Octoberto December. Consumer preference traits included tuber size, starch, low water content, taste and ease of peeling. Key problems identified were decreasing soil fertility, lack of improve varieties, labour-intensive operations, insect pests and high postharvest losses. Crop improvement should target high yielding cultivars, large tuber size, white and pink flesh and biofortification with micro-nutrients. Processing tubers into stable preservable products using low-cost roasting, dry-frying and solar dehydration methods should be evaluated. Dissemination of current improved technologies to increase productivity requires prompt attention by the Ministry of Food and Agriculture.

Research on the Optimum Shape and Size of Potato Ridges

The partial results from the research carried out in 2012 at the Potato Research and Development Station Tg. Secuiesc on the size and shape of the ridges and the influence of planting density in the case of two varieties and two types of ridges (ridges in one row and two rows) are presented. The results were heavily influenced by the unfavorable weather conditions in 2012 when there was a smaller amount of precipitation compared to the multiannual average rainfall during the growing season: -115.4 mm. The insufficient moisture resulted in the inhibition of potato tuberization, reabsorption of stolons and young tubers and in this period some of the water content in tubers passed into the leaves. In the study of the optimal shape of potato ridges three different shapes have been studied: triangular shape, trapezoidal shape and double-trapezoidal shape. In the study of the optimal size of potato ridges three different ridge sizes were made: with cross-sectional areas of 800 cm2 , 1200 cm2 and 1600 cm2. The biological material used in these two experiments was the Bella Rosa variety, which is part of the class A biological category. The research on the influence of planting density was conducted on two potato varieties planted in ridges in a single row and in two rows: one that forms many but small tubers, the class A Gared variety and the second one that forms fewer but larger tubers, the class A Bella Rosa variety. Experiments with three different planting densities for each type of variety and each type of ridge (ridges in one row and two rows) were carried out: 40.000 plants/ha, 60.000 plants/ha and 80,000 plants/ha. For all variants four rows were planted and the process was repeated four times. The common technology of ridge ploughing was used and mechanically performed phytosanitary treatments were executed with the usual products. To achieve the objectives the following elements were taken into consideration: yield and production (kg/ha), average weight of a tuber (g), average number of tubers in the nest. An analysis of variance was carried out for completely randomized plots and the data processing was accomplished by using average values, the “t-test” at 5%, 1%, 0.1% significant difference levels and the Duncan Multiple Range Test.

Significance of tuber size for complications of tuberous sclerosis complex

IntroductionTuberous sclerosis complex (TSC) is one of the most frequent neurocutaneous disorders. Cortical tubers are the most common pathological changes in TSC and they are directly related to the disease's main clinical manifestations: seizures, mental retardation, and autistic behaviour. ObjectiveThe aim of this study is to establish a correlation between tuber size and the severity of clinical features in TSC. Material and methodsWe performed a retrospective study of the clinical and imaging findings from 45 TSC patients (22 females and 23 males) and compared the clinical features with the location, size, and number of the cortical tubers in each patient. ResultsFour patients had voluminous tubers located in 1 or both cerebral hemispheres. All of these patients had intractable seizures and severe mental retardation; 3 of these cases also presented with autistic behaviour, despite tubers having been resected in all 4 patients. Thirteen patients had tubers of large-to-average size, and all patients in this group showed intractable seizures and mental retardation. Nine patients who had experienced infantile spasms during the first year of life presented autistic behaviour. Multiple tubers of small to average size were found in 28 patients. In general, this group had seizures that responded well to antiepileptic drugs and a low prevalence of autism. In 3 patients who all presented good seizure control and normal intelligence, single cortical/subcortical tubers were located in the frontal or occipital lobes. Of the total of 45 patients, 13 had cerebellar as well as cerebral tubers; these were generally present in cases with more severe clinical features. ConclusionsAlthough large tubers are less common than small to medium-sized ones, they are much more likely to be accompanied by severe clinical symptoms (seizures, mental retardation and autistic behaviour), even when the smaller tubers are quite numerous.

‘Fairytale Princess’ and ‘Red Hot’ — Red Lance-leaved Caladium Cultivars

Caladiums are valued in landscapes and containers for their colorful and variable-shaped leaves. Two types of caladium cultivars exist in commercial production: fancy- and lance-leaved. ‘Florida Sweetheart’ is the most popular lance-leaved commercial cultivar of all colors. It produces wide lance leaves with a rosy color and relatively large tubers. ‘Florida Red Ruffles’ is the most popular red, lance-leaved commercial cultivar among caladium growers, greenhouse growers, and nurseries. It has excellent sunburn tolerance. Both cultivars were introduced by the University of Florida (UF) caladium breeding program. This 9-page fact sheet was written by Zhanao Deng, and published by the UF Department of Environmental Horticulture, August 2013.
 http://edis.ifas.ufl.edu/ep481

재배조건과 수확시기에 따른 천마의 기능성 물질함량 변화

Gastrodia elata Blume is a achlorophyllous orchid plant that has been used in traditional medicine to treat many human illnesses, such as vertigo, hemiplegia, and epilepsy. It contains three major pharmacological substances; gastrodin, ergothioneine, and vanillyl alcohol. Here we investigated the quantitative changes in those functional components by cultivation conditions and harvest times. The content of ergothioneine was different with cultivation areas, while gastrodin accumulated the higher levels than vanillyl alcohol regardless of cultivation areas. The smaller tubers contained the higher concentrations of gastrodin and the lower concentrations of ergothioneine than did the larger tubers. The cultivation under sun shade screen increased the concentrations of both gastrodin and vanillyl alcohol but decreased the levels of ergothioneine. We also determined the contents of functional substances depending on the harvest times. The concentration of gastrodin was higher in October than in April, while the level of ergothioneine was higher in April than in October. Interestingly, the use of sexually propagated seed tubers produced 1.9 times higher levels of gastrodin compared to vegetatively propagated seed tubers. In this study, we found that three major functional substances in G. elata tubers altered depending on various cultivation practices, which might be important to increase the economic values of G. elata tubers.

Determination of scanned virus-free potato planting materials by positive selection and screening of tubers from seed stores in the western highlands of Cameroon

Positive selection for the identification of virus–free potato planting material was evaluated in four locations in Cameroon. Leaves from asymptomatic plants were randomly collected, the plants marked and tubers collected four weeks later, and screened with DAS-ELISA for PLRV, PVY, PVA, PVX, PVS and PVM presence. Five viruses were prevalent in leaves while four prevalent in tubers. Potato virus M was highly prevalent in leaves and tubers while PVY was high only in leaves. Potato virus A was absent in both leaves and tubers while PVX was free only in tubers. A positive correlation was observed between virus prevalence in leaves and tubers (r=0.806). The prevalence of the six viruses in potato seed tubers from four seed stores was tested. Potato virus M was the most prevalent, while PLRV was the least. Small, medium and large tuber sizes were tested for the viruses, and infection rates decreased significantly the bigger the tuber size. Positive selection though not highly efficient can be recommended for resource-poor farmers, to control the economically important potato viruses. Tuber size can serve as a guide to identify healthy tubers, but must be combined with laboratory tests for effective use in selecting seeds for planting. Keywords : Potato viruses, virus-free tubers, positive selection.

UF 4412 and UF 4424—Red Lance-leaved Caladium Cultivars

Cultivated caladiums (Caladium 3hortulanum Birdsey, Araceae Juss.) are valued for their colorful and variable-shaped leaves (Harbaugh and Tjia, 1985; Wilfret, 1993). Cultivars generally are divided into three groups according to leaf shape and size: fancy-, lance-, and strap-leaved (Wilfret, 1986). Fancy-leaved caladiums produce large round–ovate to triangular leaves with three main veins, two large basal lobes partially to fully joined, and a petiole attached to the back of the leaf blade. Strap-leaved caladiums have linear leaves with one main vein and no obvious basal lobes. Lance-leaved caladiums produce leaves intermediate between fancy and strap types: leaves sagittate to cordate–lanceolate in shape, basal lobes obvious to barely obvious, and petioles attached to the base of the leaves (Deng and Harbaugh, 2006a). The majority of caladium cultivars in commercial production are fancy-leaved (Bell et al., 1998; Deng et al., 2011). However, there has been an increasing demand for lanceleaved cultivars. Florida growers, the primary supplier of caladium tubers used in the world, reported greater than 50% more acres used for producing lance-leaved caladiums in 2008 than in 1998 (Bell et al., 1998; Deng and Alleyne, 2009; Deng et al., 2011). Plants of lance-leaved cultivars generally are more compact with smaller leaves and shorter petioles than fancy-leaved caladiums. Tubers produced by lance-leaved caladiums tend to be more branched (Deng and Harbaugh, 2008). Therefore, lance-leaved caladiums are adaptable to different container sizes, do not require tuber de-eyeing for pot plant production, and are less expensive and easier to ship from production sites to markets. These characteristics result in significant benefits to growers producing and marketing potted caladium plants (Deng and Harbaugh, 2008). Lance-leaved caladiums may be more resilient to wind damage, drought, sunburn, and shading than fancy-leaved caladiums and may do better than the latter in the landscape when such stresses occur (Deng and Harbaugh, 2008). However, many lance-leaved caladiums often produce small tubers (Wilfret, 1983). Tubers are both the planting stock and the crop for caladium growers. Thus, tuber yield is one of the most important factors determining a cultivar’s economic value for commercial production of caladium tubers. Growers cannot produce cultivars profitably without adequate tuber yield and have to eliminate them from commercial production. Thus, developing new lance-leaved caladium cultivars with adequate tuber yield potential has been a priority breeding objective for the University of Florida (UF) caladium breeding program since its beginning in 1976. Currently, ‘Florida Sweetheart’ is the most popular lance-leaved commercial cultivar of any color, and ‘Florida Red Ruffles’ is the most popular red lance-leaved commercial cultivar among caladium growers, greenhouse growers, and nurseries (Bell et al., 1998; Deng and Alleyne, 2009; Deng et al., 2011). Both cultivars were introduced by the UF caladium breeding program. Plants of ‘Florida Sweetheart’ are compact and produce wide lance leaves with a rosy color and relatively large tubers (Wilfret, 1991a). ‘Florida Red Ruffles’ has a compact, upright growth habit and excellent sunburn tolerance (Wilfret 1991b). UF 4412 (Fig. 1) and UF 4424 (Fig. 2) are attractive lance-leaved cultivars with novel, distinct combinations of plant and foliar characteristics. UF 4412 leaves are heartshaped like ‘Florida Sweetheart’ but have a large red center and numerous netted red veins. UF 4412 plants are taller and produce longer and wider leaves than ‘Florida Sweetheart’ plants. UF 4424 leaves are cordate– lanceolate-like ‘Florida Red Ruffles’ leaves but have a large, glossy, red center and numerous red, thick veins. UF 4412 and UF 4424 were comparable or superior in replicated field, greenhouse, and landscape trials

The Productivity Analysis of Five Leading Potato Varieties in the Agroecological Conditions of a Mountainous Region in Montenegro

An analysis of genetic productivity potential of five leading varieties in Montenegro (Kennebec, Agria, Aladdin, Tresor and Riviera) was conducted during 2010 and 2011 in the municipalities of Žabljak region, on mountainous black soil at 1,500 meters of altitude. The highest number of tubers was found in a parcel planted with Tresor and Aladdin- 8.5, while the lowest number of tubers was found in Kennebec- 6.8 tubers per plant. Comparing to other tested varieties, Kennebec had a significantly lower number of tubers. On average, Kennebec and Tresor had the largest tubers (96 and 91 g), and differences found were statistically very significant. The biggest tuber yield was measured in Tresor – 32.5 t/ha, while the lowest tuber yield was in Agria and Riviera (24.0 and 25.2 t/ha). Tresor had significantly higher tuber production comparing to other varieties.

Importancia del tamaño de las tuberosidades en las complicaciones del complejo esclerosis tuberosa

IntroductionTuberous sclerosis complex (TSC) is one of the most frequent neurocutaneous disorders. Cortical tubers are the most common pathological changes in TSC and they are directly related to the disease's main clinical manifestations: seizures, mental retardation, and autistic behaviour. ObjectiveThe aim of this study is to establish a correlation between tuber size and the severity of clinical features in TSC. Material and methodsWe performed a retrospective study of the clinical and imaging findings from 45 TSC patients (22 females and 23 males) and compared the clinical features with the location, size, and number of the cortical tubers in each patient. ResultsFour patients had voluminous tubers located in 1 or both cerebral hemispheres. All of these patients had intractable seizures and severe mental retardation; 3 of these cases also presented with autistic behaviour, despite tubers having been resected in all 4 patients. Thirteen patients had tubers of large-to-average size, and all patients in this group showed intractable seizures and mental retardation. Nine patients who had experienced infantile spasms during the first year of life presented autistic behaviour. Multiple tubers of small to average size were found in 28 patients. In general, this group had seizures that responded well to antiepileptic drugs and a low prevalence of autism. In 3 patients who all presented good seizure control and normal intelligence, single cortical/subcortical tubers were located in the frontal or occipital lobes. Of the total of 45 patients, 13 had cerebellar as well as cerebral tubers; these were generally present in cases with more severe clinical features. ConclusionsAlthough large tubers are less common than small to medium-sized ones, they are much more likely to be accompanied by severe clinical symptoms (seizures, mental retardation and autistic behaviour), even when the smaller tubers are quite numerous.

Effects of Limited Supplemental Irrigation with Catchment Rainfall on Rain-fed Potato in Semi-arid Areas on the Western Loess Plateau, China

In semi-arid areas on the Western Loess Plateau, China, crop growth has been greatly limited by water supply. The comparative wet season in the region runs from July through September, and about 60 % of the yearly precipitation total falls within this period. Rainfall is very sparse from November of the preceding year through June of the following year. Water harvesting agriculture has been shown to be one of the most efficient ways to increase water use efficiency (WUE) and crop productivity for wheat, corn, broccoli etc. however, research on WUE in potato (Solanum tuberosum L.), one of the dominant crops in the area, is sparse. Field experiments on supplemental irrigation (amount and timing) using catchment rainfall were carried out in both 2008 and 2009 in Dingxi, a typical potato growing area, for the purpose of determining effective utilization of the limited supplemental irrigation water for potatoes. Soil water storage, evapotranspiration (ET), WUE, irrigation water use efficiency (IWUE), tuber yield and size and starch and protein contents were determined in this research. The results showed that both ET and tuber yield increased with supplemental irrigation, consequently WUE was improved. IWUE appeared to be better with 45 mm of irrigation applied at the vegetative growth stage and tuber yield was increased by 7–18 % compared to the treatment without irrigation (T1), and WUE and IWUE were significantly higher than other treatments in both years. Compared to the control, WUE with 45 mm of irrigation at the vegetative growth stage increased by 1.28 % and 2.17 % in 2008 and 2009, respectively. In addition, 45 mm of irrigation at the vegetative growth stage also increased the percentage of large tubers, and the sum of large and medium tubers. Tubers under such practice were of acceptable size and had the highest protein content. Therefore, we conclude, 45 mm of supplemental irrigation at the vegetative growth stage is the best way to use the limited available supplemental irrigation water from catchment rainfall for rain-fed potatoes grown in semi-arid areas on the Western Loess Plateau of China. Applying more water, or at a later growth stage of potato, was less effective.

Effects of Shoot Clipping–Soil Disturbance Frequency and Tuber Size on Aboveground and Belowground Growth of Purple and Yellow Nutsedge (Cyperus rotundusandCyperus esculentus)

Purple and yellow nutsedges are two of the world's worst weeds, reproducing asexually by rhizomes that can develop into new shoots or tubers. These tubers are the storage organs for carbohydrate reserves that are replenished by growing shoots and exhausted by new shoot, root plus rhizome, and basal bulb production. Based on the biology of both species, we hypothesized that the regenerative potential of purple and yellow nutsedge would decrease, with increasing shoot clipping–soil disturbance (SCSD) frequency and decreasing tuber size. To test this hypothesis, greenhouse experiments were conducted in pots to determine the effect of SCSD frequency and tuber size on aboveground and belowground growth of purple and yellow nutsedges. Five viable tubers of two tuber category sizes (small, 0.40 ± 0.05; and large, 0.80 ± 0.05 g of tuber fresh weight) were subjected to four SCSD frequencies (weekly, biweekly, monthly, and none) for 12 wk. SCSD was performed by clipping the emerged nutsedge shoots followed by manually disturbing the soil. SCSD at biweekly or weekly intervals reduced purple nutsedge proliferation, regardless of initial tuber size. However, monthly SCSD did not suppress purple nutsedge as effectively as weekly or biweekly SCSD, and less proliferation occurred with small tubers than with large tubers. In contrast, yellow nutsedge proliferation was equally reduced with monthly or more-frequent SCSD, regardless of initial tuber size. Even weekly soil disturbance for 12 wk failed to eradicate all small or large tubers in either species. Thus, yellow nutsedge is managed more easily than purple nutsedge with less-frequent tillage or cultivation. However, tillage or cultivation alone during a 12-wk period will not likely eradicate either nutsedge species from infested soil.

Effect of Storage and Pre-sprouting Regimes on Seed Potato Performance in Norway

Physiological quality affects vigour and yield potential of potato seed tubers. Under short-season conditions, a seed tuber should preferably produce a short cycle and mature crop. The aim of the current studies was to assess how various storing and pre-sprouting treatments affect growth vigour and yield formation. Results showed that different low-temperature storage regimes before pre-sprouting treatments had no clear effects although some minor differences between treatments occurred. For pre-sprouted (‘green’-sprouted) seed tubers, results from field trials in southern Norway (2007–2008) showed that emergence of cvs Asterix and Saturna improved significantly compared to unsprouted seed. Total yields increased significantly for both cultivars in 1 out of 2 years. For Saturna, a major increase in number of tubers per plant resulted in larger proportions of smaller-size grades and thus lower marketable yields. In other trials (northern Norway, 2006–2007), varying duration of pre-sprouting did not affect growth vigour and yield. For number of tubers and size grades, the results varied significantly between pre-sprouting durations, but differently among trials, so no clear conclusions can be drawn. In one of the two trials, increased duration of pre-sprouting resulted in higher proportions of the smaller sizes at the expense of large tubers. Different levels of temperature sums during pre-sprouting (ca. 200 or 400 day-degrees >4 °C) did not affect seed performance. In conclusion, our studies showed that pre-sprouting may improve growth vigour and increase the proportion of smaller grade sizes.

M7 Germplasm Release: A Tetraploid Clone Derived from Solanum infundibuliforme for Use in Expanding the Germplasm Base for French Fry Processing

A new source of russet germplasm has been identified as a parent for processing and fresh market breeding programs. It was derived via bilateral sexual polyploidization following a cross between a diploid cultivated potato and the diploid wild species Solanum infundibuliforme. This clone, designated M7, is tetraploid and highly fertile, based on crossability to tetraploid germplasm. It produces large tubers with long shape and russet skin. M7 offspring produce tubers with a desirable appearance and some are resistant to cold-induced sweetening. In addition, M7 is resistant to common scab and soft rot.

Overcompensating plants: their expression of resistance traits and effects on herbivore preference and performance

AbstractOvercompensation is a plant tolerance response in which plants have higher fitness after herbivory than without damage. Although it has been demonstrated that plants are able to simultaneously express resistance and tolerance traits, it remains unclear whether overcompensating plants are also inducing resistance‐mediating secondary metabolite production and how herbivores perform on plants that overcompensate. Our previous work has shown that a potato variety [Solanum tuberosum L. cv. Pastusa Suprema (Solanaceae)] from Colombia can express overcompensatory responses to damage by larvae of the Guatemalan potato moth, Tecia solanivora Povolny (Lepidoptera: Gelechiidae). Here we investigated (1) whether potatoes that express overcompensatory responses also induce resistance traits and (2) how the previous damage affects Guatemalan potato moth preference and performance. Our results show that larval feeding not only systemically induces higher tuber biomass but also an increased production of resistance‐related compounds, such as phenolics and proteinase inhibitors. Pupal mass increased with increasing tuber size, whereas changes in tuber secondary metabolism did not correlate with any metric of larval performance. Oviposition preference did not change between induced and undamaged plants. Our data show that potato plants expressing overcompensatory responses also induce secondary compounds known to increase resistance against herbivores. However, the induced response was relatively small, reducing the opportunities for a negative effect on the herbivore. Hypotheses for why larvae perform better in larger tubers and are not affected by the secondary metabolism are discussed. From an ecological and agricultural point of view, our results suggest that the expression of overcompensatory traits could have positive effects on herbivore performance.

Cover Crops Can Improve Potato Tuber Yield and Quality

There is the need to develop potato (Solanum tuberosum) cropping systems with higher yields and crop quality. Field studies were conducted with cover crops grown under limited irrigation (<8 inches) to assess the effects of certain types of cover crops on potato tuber yield and quality. On a commercial farm operation before the 2006 and 2007 potato season, mustard (Brassica sp.), canola (Brassica napus), and two cultivars of sorghum-sudangrass (Sorghum bicolor × S. sudanense) were planted. A wet fallow ground treatment where no cover crop was planted was used as a control. Before the 2008 season, barley (Hordeum vulgare), barley plus applied compost, sunflower (Helianthus annus), pea (Pisum sativum), and annual ryegrass (Lolium multiflorum) cover crops were added. The results of these 2006–08 studies showed that cover crops have the potential to increase potato tuber yield and quality, as measured by tuber size (larger tubers) and appearance (e.g., tubers with reduced defects such as cracks, knobs, and misshapes). In 2 of the 3 years, most of the cover crops, especially sorghum-sudangrass, increased yields and tuber quality. Positive results from sorghum-sudangrass suggest there is potential to harvest hay from cover crops and still obtain tuber benefits.

Yellow Nutsedge (Cyperus esculentus) Growth and Tuber Production in Response to Increasing Glyphosate Rates and Selected Adjuvants

Greenhouse studies were conducted to evaluate the influence of selected adjuvants on glyphosate efficacy on yellow nutsedge and tuber production. Glyphosate was applied at 0, 0.25, 0.43, 0.87, 1.26 (1× rate), and 1.74 kg ae ha−1at 31 d after yellow nutsedge was planted. Each rate was mixed with one of the following adjuvants: ammonium sulfate (AMS), AMS plus nonionic surfactant (NIS), or AMS plus an experimental adjuvant (W-7995) plus NIS. Plants were evaluated for injury and for the number and size of tubers produced. Dose–response curves based on log-logistic models were used to determine the effective glyphosate rate plus adjuvant that provided both 90% effective dose (ED90) for yellow nutsedge injury and reduced tuber production. Addition of NIS to glyphosate plus AMS resulted in the greatest yellow nutsedge injury at 28 d after treatment (DAT). Addition of the experimental adjuvant plus NIS resulted in injury similar to NIS alone. The ED90for injury at 28 DAT was 2.12 kg ha−1with glyphosate plus AMS and NIS compared with 2.18 kg ha−1for W-7995 plus NIS and 3.06 kg ha−1with AMS alone. The ED90rates with different adjuvants represent 168%, 173%, and 243% of the highest glyphosate rate (1.26 kg ha−1) labeled for application on many glyphosate-resistant crops. However, the estimated ED90to reduce small, medium, large, and total tubers were 1.60, 1.50, 1.63, and 1.66 kg ha−1, respectively. Increases in labeled rates of glyphosate may be required to reduce yellow nutsedge tuber production in field conditions. Use of lower glyphosate rates should be discouraged because it may increase tuber production and exacerbate yellow nutsedge expansion in infested fields.

Growth and Tuberization of Hydroponically Grown Potatoes

Three hydroponic systems (aeroponics, aerohydroponics, and deep-water culture) were compared for the production of potato (Solanum tuberosum) seed tubers. Aerohydroponics was designed to improve the root zone environment of aeroponics by maintaining root contact with nutrient solution in the lower part of the beds, while intermittently spraying roots in the upper part. Root vitality, shoot fresh and dry weight, and total leaf area were significantly highest when cv. Superior, a medium early-maturing cultivar, was grown in the aeroponic system. This better plant growth in the aeroponic system was accompanied by rapid changes of solution pH and EC, and early tuberization. However, with cv. Atlantic, a mid-late maturing cultivar, there were no significant differences in shoot weight and leaf area among the hydroponic systems. The first tuberization was observed in aeroponics on 26–30 and 43–53 days after transplanting for cvs Superior and Atlantic, respectively. Tuberization in aerohydroponics and deep-water culture system occurred about 3–4 and 6–8 days later, respectively. The number of tubers produced was greatest in the deep-water culture system, but the total tuber weight per plant was the least in this system. For cv. Atlantic, the number of tubers 30 g between aerohydroponics and aeroponics. For cv. Superior, there was no difference in the size distribution of tubers between the two aeroponic systems. It could be concluded that deep-water culture system could be used to produce many small tubers (1–5 g) for plant propagation. However, the reduced number of large tubers above 5 g weight in the deep-water culture system, may favor use of either aeroponics or aerohydroponics. These two systems produced a similar number of tubers in each size group for the medium-early season cv. Superior, whereas aerohydroponics produced more tubers than aeroponics for the mid-late cultivar Atlantic.

Microarray identification of conserved microRNAs in Pinellia pedatisecta

Large numbers of microRNAs (miRNAs) reportedly play important roles in plant development. However, none has been reported in Pinellia pedatisecta, an important aroid medicinal plant that possesses the only pedate leaf blades and the largest tubers and inflorescences among all Pinellia species. To detect the miRNAs from P. pedatisecta, an in situ synthesized custom miRNA microarray was employed, following the verification for the presence of the miRNAs through reverse transcription polymerase chain reaction (RT-PCR) and the quantitative RT-PCR (qRT-PCR). A total of 99 miRNAs belonging to 22 miRNA families were identified. The RT-PCR was applied to 14 miRNAs detected to validate the microarray results. The qRT-PCR that targeted seven miRNAs showed different expression levels of miRNAs in different tissues. The current research is the first to report on the miRNAs in P. pedatisecta and will enable further investigation of their roles in P. pedatisecta development.

Effect of compost and animal manure with phosphorus and zinc fertilizer on yield of seed potatoes

This study was carried out to investigate the effect of compost and manure with phosphorus and zinc on potato yield (Solanum tuberosum L.). The experiment was conducted in the Kerman agricultural and natural resources research centre (Iran) by using a factorial design in randomized complete block in two independent experiments with three replications. In the first experiments compost with phosphorus and zinc were used, and in second experiment animal manure with phosphorus and zinc were used. The three levels of compost (0, 10 and 20 ton ha-1) and same level of animal manure were used as main. Four levels of phosphorus (0, 75, 150 and 225 kg ha-1) and two levels of zinc (0 and 50 kg ha-1) used as the sub factors. Results showed that the main factors of compost and animal manure application had no significant effect on any of the all evaluated traits in the experiments. Effect of zinc on number of small tubers was significant in the first experiment. The highest number of large tubers were found in 20 ton ha-1 compost + 225 kg ha-1 phosphorus + 50 kg ha-1 zinc in first experiment and 20 ton ha-1 animal manure + 75 kg ha-1 phosphorus + no zinc in second experiment. Tubers dry matter was significantly affected by the interaction effect of zinc and phosphorus, the maximum dry matter being obtained with the application of 225 kg ha-1 phosphorus +50 kg ha-1 zinc.

Adubação orgânica e inorgânica de batatinha em solos arenosos: produtividade, nutrientes na planta e lixiviação

As relações entre os teores de nutrientes em solos com adubação orgânica e inorgânica e os teores de nutrientes e produtividade de batatinha foram determinadas tal como as relações entre aportes e a lixiviação de N e bases trocáveis. Amostras de solo foram coletadas das camadas de 0-20, 20-40 e 40-60 cm em 18 áreas de produção com adições anuais de esterco variando entre 2 e 40 anos e, como controle, quatro áreas sob pastagem não adubadas. Amostras de solo e planta foram analisadas quanto aos teores de N, P, K, Ca e Mg. A produtividade de tubérculo com padrão comercial apresentou relação positiva com a quantidade de N aplicada e a produtividade total indicou relação com o estoque de N do solo; somente o Ca no solo se correlacionou com os teores na planta mas não com a produtividade. As bases trocáveis aumentaram nas três camadas, de acordo com o aumento do esterco aplicado enquanto no N total o aumento só ocorreu nas camadas de 0-20 e 20-40 cm; por fim, a translocação de nutrientes para camadas mais profundas representa prejuízo econômico e provável risco ambiental.