Early Potato Research Articles

A field trial to assess damage by <i>Bactericera cockerelli</i> to early potatoes at Pukekohe

An early season potato trial at Pukekohe assessed the damage caused by Bactericera cockerelli tomatopotato psyllid (TPP) and investigated the need for insecticide treatment Four treatments were used insecticide drench at planting; insecticide drench and weekly foliar sprays; insecticide drench and thresholdbased foliar sprays; and no insecticides TPP and associated insects in the trial were monitored weekly using yellow sticky traps and sampling plants from midOctober until midDecember 2011 TPP adult catches remained very low reaching 15 per trap per week in December and egg and nymphal infestations were absent or very low Other exotic psyllid species dominated trap catches in December The predator Micromus tasmaniae (brown lacewing) was the most common insect present throughout the trial peaking at a combined total of 66 eggs and adults per plant No damage was caused by TPP in any treatments indicating that insecticides may not be required to produce healthy early crop potatoes at Pukekohe

Tuber yield, water and fertilizer productivity in early potato as affected by a combination of irrigation and fertilization

Excessive amounts of irrigation water and fertilizers are often utilized for early potato cultivation in the Mediterranean basin. Given that water is expensive and limited in the semi-arid areas and that fertilizers above a threshold level often prove inefficacious for production purposes but still risk nitrate and phosphorous pollution of groundwater, it is crucial to provide an adequate irrigation and fertilization management. With the aim of achieving an appropriate combination of irrigation water and nutrient application in cultivation management of a potato crop in a Mediterranean environment, a 2-year experiment was conducted in Sicily (South Italy). The combined effects of 3 levels of irrigation (irrigation only at plant emergence, 50% and 100% of the maximum evapotranspiration – ETM) and 3 levels of mineral fertilization (low: 50, 25 and 75 kg ha−1, medium: 100, 50 and 150 kg ha−1 and high: 300, 100 and 450 kg ha−1 of N, P2O5 and K2O) were studied on the tuber yield and yield components, on both water irrigation and fertilizer productivity and on the plant source/sink (canopy/tubers dry weight) ratio. The results show a marked interaction between level of irrigation and level of fertilization on tuber yield, on Irrigation Water Productivity and on fertilizer productivity of the potato crop. We found that the treatments based on 50% ETM and a medium level of fertilization represent a valid compromise in early potato cultivation management. Compared to the high combination levels of irrigation and fertilization, this treatment entails a negligible reduction in tuber yield to save 90 mm ha−1 year−1 of irrigation water and 200, 50 and 300 kg ha−1 year−1 of N, P2O5 and K2O, respectively, with notable economic savings for farmers compared to the spendings that are usually made.

Suitability of 4 Potato Cultivars (Solanum tuberosum L.) to be Processed as Fresh-Cut Product. Early Cultivars

The study of the suitability of potato cultivars to be processed as fresh-cut is the first step to obtain a fresh-cut product of high quality. In this study, 4 different early potato cultivars (‘Ariana’, ‘Liseta’, ‘Safrane’ and ‘Spunta’) were cut and stored for 8 days at 5°C and for 6 days at 20°C with the aim to investigate their browning potential and their post-cutting performance on the basis of their initial quality attributes such as color, polyphenol oxidase (PPO) activity, total phenolics, ascorbic acid contents, sugar composition and antioxidant activity (AOX). In addition, color changes and general appearance were monitored during storage, and a study of the correlations among monitored parameters was carried out. Results showed that ‘Safrane’ had the least color changes and browning incidence. At 5°C, ‘Safrane’ showed only about 1% variation in L*, statistically lower than ‘Spunta’ (3.6%) and ‘Ariana’ (5.1%), and presented the lowest variation in a* value (about 50% vs. 70% for all other cultivars). At 20°C, ‘Safrane’ and ‘Liseta’ showed a lower decrease in L* (5.6 and 6.2%, respectively) and ΔE values, (6.0 and 6.1%, respectively), but ‘Spunta’ and ‘Ariana’ were the cultivars with the highest decrease in these parameters. ‘Safrane’ also received the highest appearance score during the first days of storage at both storage temperatures, and had a high ascorbic acid content (31.2 mg/100 g fw) and antioxidant activity (26.6 mg TE/100 g fw). ‘Liseta’ and ‘Ariana’ showed intermediate potential in terms of storability and appearance, while ‘Spunta’ was the least suitable to be used as fresh-cut. Results of this work contributed to increased knowledge on the suitability of potato cultivars to be processed as fresh cut produce, to allow the fresh-cut industry to be supplied with raw material suitable for processing throughout the year, according to seasonal availability.

Soil properties, strontium isotopic signatures and multi‐element profiles to authenticate the origin of vegetables from small‐scale regions: illustration with early potatoes from southern Italy

We propose a method for the authentication of the origin of vegetables grown under similar weather conditions, in sites less than 10 km distance from the sea and distributed over a rather small scale area (58651 km(2)). We studied how the strontium (Sr) isotopic signature and selected elemental concentrations ([Mn], [Cu], [Zn], [Rb], [Sr] and [Cd]) in early potatoes from three neighbouring administrative regions in the south of Italy were related to the geological substrate (alluvial sediments, volcanic substrates and carbonate rocks) and to selected soil chemical properties influencing the bioavailability of elements in soils (pH, cation exchange capacity and total carbonate content). Through multiple-step multivariate statistics (PLS-DA) we could assign 26 potatoes (including two already commercialised samples) to their respective eight sites of production, corresponding to the first two types of geological substrates. The other 12 potatoes from four sites of production had similar characteristics in terms of the geological substrate (third type) and these soil properties could be grouped together. In this case, more discriminative parameters would be required to allow the differentiation between sites. The validation of our models included external prediction tests with data of potatoes harvested the year before and a study on the robustness of the uncertainties of the measurement results. Annual variations between multi-elemental and Sr isotopic fingerprints were observed in potatoes harvested from soils overlying carbonate rocks, stressing the importance of testing long term variations in authentication studies.

Analysis of Business Performance in the Case of Mixed Farm

The economic analysis of business process on the mixed farm in Prekmurje region in Slovenia was performed. For the assessment of farm business analysis specific technologic-economic simulation model with sub-models were developed. The analysis showed that the most economically feasible vegetable product is onion (Financial result,    FR = 2 783.71 € and Coefficient of economics, Ce = 2.24). Among the analyzed field crops is economically the most interesting production of oil pumpkins (FR = 1 920.84 € and Ce = 2.13). The analysis showed that the production of analyzed crops without direct payments is economically unfeasible. Further, linear optimization program for optimization farm production plan was presented too. Considering financial results maximization, production total cost minimization, as well as other resource limitation, in the production plan, the most advantageous combination is one of barley and oilseed rape by the scenario 1. In scenario 2, early cabbage, onion and early potatoes production were suggested. By the scenario 3 barley, red onions, and silver onions is defined. By the last scenario 4 onions and pumpkin oil production is suggested.

Gender analysis in agricultural enterprises producing early potatoes in the Adanaprovince of Turkey

Given gender, there exists an unequal social structure between women and men related to education, division of labour, occupation structure etc. This discrimination is rather sharp especially for women working in the agricultural sector and the agricultural enterprises in Turkey, which produce early potatoes, which can be taken as a good example for this paper. In this study, the gender structure in the enterprises in Adana, producing early potatoes was analysed in terms of the owner of the enterprise and his wife and women working as agricultural workers and their spouses. The data was obtained in the villages producing early potatoes in the years 2008 to 2009 through individual interviews and statistical analysis. As a result of the study, it is evident that women are generally oppressed; moreover, female seasonal workers have certain disadvantages compared to both men and their counterparts living in urban areas. Key words: Gender, seasonal women worker, division of labour, early potato, Turkey.

Traceability and Demand Sensitiveness: Evidences from Italian Fresh Potatoes Consumption

When a traceability system takes place, either when mandatory or voluntary, many questions arise that need to be addressed and answered. One of the firsts concerns whether it introduces new costs with no gain in efficiency or, on the contrary, the system efficiency increases lowering costs and, as a consequence, market price of the good in hand. Among others, another issue that only rarely is addressed regards the effect of a price change on the final market. The objective of this paper was to simulate the effect on fresh Italian vegetables market of prices change due to a newer traceability procedure, focusing on early potato. Reasons why early potato was the main object of our study will be explained in detail later in the paper. Moreover, this study concerns a demand system estimation that has, as main goal, the measurement of own and cross price elasticities as well as expenditure elasticities. Such estimations are not strictly related with traceability because they measure any change in quantity demanded due to price changes due to any market perturbation. However, since early potato is experiencing a peculiar market and chain change in Italy, our simulation is meant to reason in terms of a “what if” approach, formally simulating the effect of any change in price due to an hypothesis of traceability system involved. In order to estimate a demand system, real household consumption data (3,000 observations) of a statistically representative sample of the Italian population of households was taken into account. Relevant measures of market variables were estimated by means of a Linear Almost Ideal Demand System implementing a large set of fresh vegetables: potato split in early and late, cabbage, salad, mushrooms, fruits vegetables, roots, asparagus, onion, tomatoes, peppers, cucumbers, beans, zucchinis and others.

PP 1/143 (3): Potato desiccants

Specific scopeThis standard describes the conduct of trials for the efficacy evaluation of desiccants on seed potatoes for rapid desiccation of the haulms without damaging the tubers. Haulm destruction is essential for seed potato production and may also be used for other potatoes (although not generally for early potatoes).Specific approval and amendmentFirst approved in 1989–09.Revision approved in 2010–09.

The effect of microwave radiation on the germination process of stored potato tubers

The purpose of the present paper was to study the effect of microwave radiation on the number and weight of sprouts appearing on potato tubers after its storage. The studies included three early potato cultivars (Felka Bona, Rosara and Velox), whose tubers were radiated with microwaves with the frequency of 2.45 GHz for the period of 10, 20 and 60 s. Results of the experiment show that microwave radiation significantly modifies the germination process of the stored potato tubers.

ECONOMIC AND ENVIRONMENTAL ASSESSMENTS OF VEGETABLE ROTATIONS IN NORWAY USING THE EU-ROTATE_N MODEL

ISHS IV International Symposium on Ecologically Sound Fertilization Strategies for Field Vegetable Production ECONOMIC AND ENVIRONMENTAL ASSESSMENTS OF VEGETABLE ROTATIONS IN NORWAY USING THE EU-ROTATE_N MODEL

The effect of municipal wastewater irrigation on the yield and quality of vegetables and crops

The effect of municipal wastewater irrigation on the yield and quality of vegetables and crops was studied by means of pot and lysimetric experiments. The pots were seeded with lettuce salad, radishes, and carrots in all experimental years; the lysimeters were planted with early potatoes in 2005 and 2007, and with sugar beet in 2006. Secondary-treated wastewater (in 2005) or only primary-treated wastewater (in 2006 and 2007) were used in the experiments. The control treatment involved the irrigation with water from a local well (in 2005) or public water supply (in 2006 and 2007). Contrarily to the secondary-treated wastewater, the primary-treated wastewater increased the yield of all vegetables and crops, the increase having been statistically significant in most cases. The irrigation with secondary-treated wastewater increased only the sodium content in radishes and carrots. However, the irrigation with primary-treated wastewater led to a statistically significant increase in the sodium content in the consumable parts of all vegetables, sugar beet bulbs, and potato tubers in both years, and in 2007, in the nitrate contents in lettuce salad and radishes as well. A high bacterial contamination of vegetables and crops irrigated with this wastewater was found out, but there was no evidence for the contamination with pathogens. Also, no risk was shown of contamination of the crops with intestinal nematodes.

Effects of seed size and in-row spacing on growth and yield of early potato in a mediterranean-type environment in Turkey.

Optimizing plant density and seed size are the most important subjects of early potato production systems in mediterranean-type environments due to their effects on seed cost, plant development, yield and quality of the crop. The effects of different in-row spacing (20, 25, 30 and 35 cm) and seed size (small, medium and large) treatments on yield components and tuber yield of early potato were studied in Adana, where is situated in the east mediterranean region of Turkey, during 2006 and 2007 growing seasons. It was determined that closer spacing reduced tuber number per hill, average tuber weight, tuber yield per hill and percentages of large and medium size tubers. Total yields increased as increasing planting density up to 20 cm spacing. Planting larger seeds positively affected all growth and yield components in both years. Tuber yield per hectare was increased up to certain stem density and then started to decline at all seed sizes. However, the optimum stem density for the maximum tuber yield per hectare markedly differed depending on size of seed tubers. The optimum stem density increased with increasing seed size. Our findings indicated that size of seed tuber has further importance for growth of potato plant as well as competition aspect in early potato production in the mediterranean-type environments. Hence it was concluded that using larger tubers had an advantage for vigorous early growth and for obtain high tuber yield in early potato production in the mediterranean-type environments. Seed size should be considered during recommendation for planting density in potato production. Key words: Seed size, in-row spacing, early potato, competition.

Yield and quality of early potato cultivars in relation to the use of glufosinate‐ammonium as desiccant

AbstractBACKGROUND: Glufosinate‐ammonium (GA) is used for chemical vine killing of potato crop before harvest. Over two years we tested the effect of GA, applied at 0.48 kg ha−1 of active ingredient, on desiccation of haulms, yield and some qualitative traits of tubers of three cultivars of early potatoes, a typical crop of southern Italy and large areas of the Mediterranean countries.RESULTS: Seven days after treatment desiccation reached 90% of leaves for all cultivars. At harvest, the highest desiccation percentage of haulms was 85% in Spunta. The desiccant did not affect yield in either year during which the analysis was carried out, but it increased the percentage of tubers in the range of 35–70 mm in diameter. In the first year, the treatment decreased dry matter and vitamin C content and increased free sugar concentration in tubers. In the second year, no negative effects on the nutritional traits were observed. Strong differences were found on yield and quality between the two years as a result of the different climatic conditions.CONCLUSION: In the two experiments GA had no influence on yield, but increased the percentage of potato tubers in the 35–70 mm range. From a qualitative standpoint in 2004 the chemical vine‐killing treatment had some negative effects (decreased dry matter and vitamin C content, increased free sugar concentrations), whereas no such negative effects were observed in 2005. Copyright © 2009 Society of Chemical Industry

Tuber quality and nutritional components of “early” potato subjected to chemical haulm desiccation

“Early” potato is a typical crop grown in most of the Mediterranean countries, and it is one of the most important horticultural crops exported towards the Northern European markets. In order to improve market value of early potatoes, growers are more and more involved in choosing new potato varieties and constantly looking for methods to improve the commercial quality of tubers. One of the most increasingly used agro-techniques is chemical haulm desiccation, which aims to simplify harvesting and can help to manipulate tuber size distribution and tuber skin-set. Its effect on yield and quality aspects of early potato remains to be better evaluated. This paper resumes results of trials and analysis conducted during 2007 concerning the effect of the application of a chemical desiccant (gluphosinate ammonium) on some relevant nutritional parameters of three early potato varieties (Spunta, Ditta, and Krone) grown in Southern Italy. Tubers from the trials were analyzed for tuber size distribution, flesh and skin colour, dry matter, nitrate, soluble carbohydrates, total and resistant starch, vitamin C, phenol content, and total antioxidant activity. Results indicate that chemical desiccation does not affect the levels of vitamin C and those of other molecules with antioxidant properties as well as those of total soluble carbohydrates. On the other hand, it induces a significant decrease in starch storage and an increase in the percentage of resistant starch (a component of dietary fibre).

Effect of perforated foil and polypropylene fibre covers on growth of early potato cultivars

This paper presents the results of a three-year research on the effect of perforated polyethylene foil and polypropylene fibre covers on the growth of early potato cultivars at various lengths of plant covering period (2 and 3 weeks after plant emergence). Plants grown under covers were higher, produced higher mass of above-ground parts, and were characterised by a smaller value of leaf weight ratio (LWR) and leaf area ratio (LAR) compared with the cultivation without covering. In the case of plant covering for 2 weeks after emergence the mass of leaves at the time of cover removal was on average almost 2 times higher and the mass of stems over 2.5 times higher than in the cultivation without covering; the values of LWR and LAR were however smaller by 0.094 and 0.137 m<sup/kg, respectively. At the 3-week period of plant covering the differences in the mass of above-ground parts were a little smaller than at 2-week period of plant covering, and LWR and LAR were 1.4 times and 2.3 times higher, respectively. The research showed a significant effect of type of cover used on plant growth. When perforated foil was used, plants were higher and produced more mass of above-ground parts compared with polypropylene fibre usage. The most favourable effect of perforated foil covering was observed in the year with the lowest air temperature in May; 2 weeks after plant emergence, the use of perforated foil resulted in the mass of leaves and stems 1.5 times and 2.2 times as high as with the polypropylene fibre, respectively. The differences were lower when plants were covered for 3 weeks. The use of polypropylene fibre resulted in higher LWR and LAR by 0.060 and 0.276 m<sup/kg, respectively, after 2 weeks from plant emergence, and by 0.072 and 0.328 m<sup/kg after 3 weeks from plant emergence.

Yield formation and quality characteristics of early potatoes during a short growing period

The effects of nitrogen fertilization on the yield and quality of early potato (Solanum tuberosum L.) were studied at MTT Agrifood Research Finland during 1996–1997. Cultivars were harvested at three times. The experimental layout was a split-split-plot with harvest times as main plots and nitrogen fertilization and potato cultivars as the subplots. The fertilizer treatments were 60 and 120 kg N ha-1 and the cultivars tested were Timo, Gloria and Van Gogh. The harvest times were 57–62, 70–75 and 85–90 days after planting. Application of 120 kg N ha-1 intensifi ed canopy development and increased leaf area of the stands. At early harvest the tuber yield of all cultivars receiving the higher nitrogen application increased by 0.5–2.5 t ha-1. The highest yielding cultivar was Timo. At last harvest, the higher nitrogen treatment increased yield by 3.0–6.2 t ha-1. The highest yielding cultivars were Timo and Van Gogh. The dry matter content of tubers was very low, 13.8–17.2%, at the fi rst harvest and the higher nitrogen application reduced dry matter content by 0.3–1.0%. The highest fertilizer application rate resulted in the largest tuber size. Nitrogen application, however, affected the quality of potatoes by decreasing the dry matter content. The nitrate content in tubers increased signifi cantly with the increasing level of nitrogen. The range of nitrate content in tubers fl uctuated between 13 and 189 mg kg-1 fresh weight showing good controlling of nitrate values. Harvest time affected sucrose content and the reducing sugar content in tubers, but nitrogen fertilizer did not change the sugar content of tubers. As tuber yield and quality during a short growing season are affected mainly by intercepted radiation, methods to increase tuber yield should focus on reducing the time to emergence, improving haulm growth after emergence and increasing the harvest index.;

Tracing the geographical origin of early potato tubers using stable hydrogen isotope ratios of methoxyl groups†

The application of stable isotope ratio measurements has become an extremely useful tool for tracing the provenance of food products, thus ensuring that consumers receive products which comply with their labelled specifications. Recently, it has been shown that relative stable hydrogen isotope abundances (δ2H values) of wood lignin methoxyl groups have a distinct range that reflects the δ2H values of their meteoric source water. Furthermore, it has been suggested that the isotope information stored in methoxyl groups in plant matter generally might assist with determining the place of origin of plant material. We now have measured δ2H values of methoxyl groups from natural compounds in tubers of early potatoes (Solanum tuberosum) grown in different geographical locations. Tubers of early potatoes were collected from across Europe and regions close to the Mediterranean Sea between April and July 2004. The methoxyl groups from the potatoes were found to be highly depleted in 2H, relative to both their meteoric water and bulk biomass, and a systematic shift of the δ2H values between methoxyl groups and meteoric water was observed. A constant fractionation of−161±11‰. between methoxyl groups and modelled meteoric water is shown over a transaction covering the δ2H values of meteoric water from−95‰ in Northern Sweden to+25‰ in Egypt. From this information, early potato tubers from Middle Europe can be clearly distinguished from those of Mediterranean regions and from Northern Europe. Thus, we suggest that δ2H values of methoxyl groups have the potential to become an effective tool in assisting with the constraint of the geographical origin of potato tubers and other food stuffs. †Revised version of a paper presented at the 30th Annual Meeting of the German Association for Stable Isotope Research (GASIR), 8–10 October 2007, Bayreuth, Germany.

Dielectric properties of deformed early potatoes

The permittivity of potato tissue was studied during uniaxial compression of cylindrical specimens prepared from two early varieties. Both the real and the imaginary permitivity components were determined repeatedly during the loading and unloading tests. The analysis of the results obtained shows that small differences exist between the permittivity of the late and early potato varieties. The differences are concentrated mainly at frequencies higher than 1 kHz with a maximum between 10 and 100 kHz. The effect of deformation is concentrated into frequencies between 1 and 100 kHz. The effect of deformation on the permittivity values can be divided into reversible and irreversible parts. The results obtained in the loading/unloading tests give some more information on the proportion of both parts.

Antioxidant Compounds and Antioxidant Activity in “Early Potatoes”

The antioxidant content and the antioxidant capacity of both hydrophilic and lipophilic antioxidant extracts from four "early potato" cultivars, grown in two different locations (Racale and Monteroni), were examined. There was a considerable variation in carotenoid content and weak differences in the ascorbic acid concentration of the examined cultivars of "early potato" and between the harvested locations. An increase in both methanol/water (8:2 v/v) and phosphate buffer soluble (PBS) free phenols (70%) and bound phenols (28%) in the extracts from the cultivars grown at Racale site was found and discussed. Examination of individual phenols revealed that chlorogenic acid and catechin were the major phenols present in potato tuber extracts; a moderate amount of caffeic acid and ferulic acid was also detected. The total equivalent antioxidant capacity (TEAC) was higher in the Racale extracts and a highly positive linear relationship ( R (2) = 0.8193) between TEAC values and total phenolic content was observed. The oxyradical scavenging capacity (TOSC) of methanol/water and PBS extracts of peel and whole potatoes against the reactive oxygen species (ROS) peroxyl radicals, peroxynitrite, and hydroxyl radicals was also analyzed. A highly significant linear correlation ( R (2) = 0.9613) between total antioxidant capacity (as a sum of peroxyl radicals + peroxynitrite) and total phenol content of methanol/water extracts was established. Moreover, proliferation of human mammalian cancer (MCF-7) cells was significantly inhibited in a dose-dependent manner after exposure to potato extracts. These data can be useful for "early potato" tuber characterization and suggest that the "early potato" has a potential as a dietary source of antioxidants.

Influence of the thermal shock and pre-sprouting on potato tuber yield

Thermal shock and pre-sprouting increase the initial development of potato (Solanum tuberosum L.) plants, allowing for earlier harvests. Growing early potatoes without pre-sprouting is not economically viable under Nordic climatic conditions. The aim of this research was to determine how seed tuber pre-planting treatments (untreated, thermal shock and pre-sprouting) influence time to emergence, mean tuber weight, the number of tubers per plant, and yield (including yield dynamics). The main findings of this work were that thermal shock shortened the time to emergence by 2-5 days, while pre-sprouting shortened it by 7-12 days. In addition, thermal shock significantly increased the number of tubers produced, although their mean weight was lower than that of the tubers produced by the pre-sprouted plants. The presprouted tubers provided a very early harvest of large tubers; the harvest time for the thermal shock-treated tubers was a little later. The untreated seed tubers were the last to produce harvestable plants.