In the field trials performed between the years 2019 and 2021 the effect of weeds was investigated on potato yield and quality and at the same time the effect of selected herbicide active ingredients used prior to potato crop emergence or early after the emergence was determined. Weed infestation is highly current topics in the conditions of applied potato growing technologies in the Czech Republic. The transfer to de-stoning technology at the end of the last century meant a reduction of mechanical tuber damage; however, it excluded mechanical destruction of weeds. In the trials following active ingredients were used: flurochloridone, metribuzin + prosulfocarb, metribuzin + clomazone, metribuzin + flufenacet, aclonifen, metribuzin + flufenacet + aclonifen, metobromuron + prosulfocarb, metobromuron + aclonifen. All tested variants of herbicide active ingredients and their combinations provided a good weed control efficacy. The trial variants had a highly significant effect on potato yield. Compared to non-treated control potato yield was increased in the range of 44.1 % (metribuzin + prosulfocarb) and 112 % (metobromuron + aclonifen). An application of metribuzin + prosulfocarb combination early after emergence had a negative impact on potato growth and it resulted in low potato yield insignificant across years with non-treated control in contrast with all other variants. The highest potato yield and corresponding high weed control efficacy was determined in variants with metabromuron combinations (Var. 9 metabromuron + prosulfocarb and Var. 10 metabromuron + aclonifen). The evaluated variants had no impact on studied quality indices (tuber size distribution after harvest and starch content).

The study was aimed at verification of an effect of weed management in potatoes under conditions of de-stoning technology in the Czech Republic. Potato Research Institute in Havlickuv Brod realized a three-year field trial that involved active ingredients of herbicides applied pre-emergently (flurochloridone, metribuzin + clomazone, metribuzin + flufenacet, metribuzin + prosulfocarb, metobromuron + prosulfocarb, aclonifen) and post-emergently (metribuzin + rimsulfuron and bentazone) into potatoes. The efficacy was observed on present weeds Fallopia convolvulus, Matricaria chamomilla, Chenopodium album, Viola arvensis, Capsella bursa pastoris and Lamium purpureum in comparison to non-treated variant and further on total and marketable potato yield. All active ingredients reached weed control efficacy in the range from 56 % (bentazone) to 100 % (metobromuron + prosulfocarb) across the years. Fallopia convolvulus was determined as the most distributed weed. The most effective combinations against this weed species involved pre-emergently applied metribuzin + flufenacet and metobromuron + prosulfocarb. Pre-emergently applied herbicides indicated higher efficacy compared to post-emergent applications. The combinations of metribuzin + clomazone, metribuzin + prosulfocarb and metobromuron + prosulfocarb indicated a significant effect on the highest total and marketable potato yield.

The aim of this research was verification of drip irrigation effect on potatoes under conditions of higher regions in the Czech Republic. Growing technology using drip irrigation combined with fertigation was verified. After the planting irrigation pipes were put under the soil surface on the ridge top. Two cultivars s differing in vegetation duration were used for planting - early cultivar Monika and medium-early cultivar Jolana. Eight variants of irrigation combined with N fertilization were established. A technique for irrigation management was determined based on soil conditions. Nitrogen fertilization during season was done in two variants: 120 kg N ha(-1) prior to planting and 60 kg N ha(-1) at planting + 60 kg N ha(-1) in four irrigation rates (15 kg N ha(-1) for each). In the trials an effect of irrigation on all studied factors was detected. Potato yield was significantly increased in variants with irrigation compared to nonirrigated variants. There were no differences found between full and split N rate application.

The aim of this research was verification of drip irrigation effect on potatoes under conditions of higher regions in the Czech Republic. Potato Research Institute in Havlickuv Brod realized a project directed to evaluation of new technological procedures for effective water management under drought conditions between 2016 and 2017. Growing technology using drip irrigation combined with fertigation was verified. After the planting irrigation pipes were put under the soil surface on the ridge top. Two cultivars differing in vegetation duration were used for planting - early cultivar Monika and medium-early cultivar Jolana. Eight variants of irrigation combined with N fertilization were established. A technique for irrigation management was determined based on soil conditions. Nitrogen fertilization during season was done in two variants: 120 kg N ha(-1) prior to planting and 60 kg N ha(-1) at planting + 60 kg N ha(-1) in four irrigation rates (15 kg N ha(-1) for each). In the trials an effect of irrigation on all studied factors was detected. Potato yield was significantly increased in variants with irrigation compared to non-irrigated variants. There were no differences found between full and split N rate application. Drip irrigation increased volumetric soil moisture on optimal level for potato plant growth. A device was constructed for burying drip pipes under soil surface on the ridge top, which could be also used for pipe extraction after haulm desiccation before potato harvest.

To verify the possibility of volunteer potato control in subsequent crops of the crop rotation (maize and cereals) field trials were established in the Potato Research Institute (Valecov Research Station) between 2013 and 2016. Following active ingredients were used for control: fluroxypyr, mesotrione, foramsulfuron, iodosulfuron-methyl Na and thiencarbazone-methyl. Compared to non-treated control a significant effect of evaluated active ingredients on reduction of potato tuber weight was found. The highest efficacy (80.7 %) was recorded for fluroxypyr (300 g/ha). Using a reduced rate (200 g/ha) of fluroxypyr the efficacy was reduced to 72.9 %. The combination of foramsulfuron (45 g/ha), iodosulfuron-methyl Na (1.5 g/ha) and thiencarbazone-methyl (15 g/ha) reached the efficacy of 73.5 %. The lowest efficacy (59.7 %) was recorded for mesotrione (144 g/ha).

A field trial performed in the locality Valecov between 2014 and 2015 was focused on comparison of digestate with a typical mineral fertilizer. In total, three variants were established with four replications: 1) 100 % nitrogen in urea (120 kg N ha(-1)); 2) 100 % nitrogen in digestate (120 kg N ha(-1)); 3) 150 % nitrogen (180 kg N ha(-1)). The effect of fertilization variants was studied on yield and quality parameters of ware potatoes. The obtained results show that year of growing had a significant effect on potato yield and quality, especially in 2015, when yields were to a certain extent affected by extreme drought. Potato yield, particularly in 2014, was positively affected by variants with digestate compared to urea and simultaneously, no significant effect was found on internal tuber quality. On the average of years, the highest yields were tendentiously recorded for the variant with digestate rate of approx. 120 kg N ha(-1) compared to the other variants.

Between years 2011 and 2013 field trials were established with potatoes involving various variants of herbicide applications using recommended rates and 50 % reduced rates. The research was done in 3 replications using de-stoning technology and the early ware potato variety Dali was involved. The aim was to determine, whether low input system could be applied in de-stoning technology for potato growing and whether recommended rate of herbicide could be 50 % reduced while maintaining required level of weed control effect and the same yielding level.. The trials show that 50 % reduction of herbicide rate did not have an effect on potato yield. Weed control efficiency, measured toward the end of vegetation, was not reduced in the first trial year due to variants with reduced herbicide rate; in following two trial years the efficiency was 8-12 % reduced. However, this reduction was not expressed in potato yields. The reason is that efficiency reduction did not reach threshold of harmfulness of weed species. Significant differences in potato yields were not found between variants, except for the variant without treatment.From research standpoint reduced herbicide application could be recommended.

In three-year field trials reducing sugar (RS) and asparagine (Asn) content was measured in raw potatoes, fried chips from three potato varieties grown with four variants of nitrogen and sulphur fertilization. RS content was statistically affected by year and variety. In dry and warm year the lowest RS content was determined. All studied factors, i.e. year and also variety and fertilization variants had a statistical important effect on Asn content. The relation of Asn and year is opposite than for RS, significantly the highest content was found in year with highest rainfall deficit. The results indicate tendency to higher Asn and also acrylamide contents with increased rates of nitrogen fertilizers. Sulphur fertilizer did not positively influence decrease of Asn content as referred several data from literature.Based on trial results the relation was calculated between acrylamide precursors and acrylamide final content in fried chips. Whereas in case of RS content linear dependence was confirmed, in case of Asn content did not detect any dependence.

The impact of selected factors – cultivar, storage, cooking and baking on the content of total anthocyanins (TAC) in coloured-flesh potato cultivars has been studied. TAC ranged from 248.5 to 2257.8 mg kg−1 dry matter (DM). TAC difference between cultivars was statistically significant. Cold storage (4 °C) influenced TAC differentially. In the Violette and Highland Burgundy Red cultivars TAC increased by 18.5% and 12.1% respectively, and in the Valfi cultivar it decreased by 33.9%. Baking increased TAC 3.34 times whereas cooking in boiled water increased it 4.22 times. Correlation between antioxidant activity (AOA) and TAC (r2 = 0.659) has been found. The Violette, Vitelotte and Highland Burgundy Red cultivars with the highest TAC showed high AOA and the Shetland Black cultivar and the cultivars Salad Blue and Blue Congo with a “marbled” texture showed the lowest TAC and AOA. Individual anthocyanidins are fingerprints of colour-fleshed potato cultivars.

Jerusalem artichoke (Helianthus tuberosus) is a not widely grown crop. It is universally usable, in human diet (source of inulin), for livestock feeding and as an energy crop. In field trials performed in Valecov Research Station belonging to PRI Havlickuv Brod, during 2008 - 2010 an effect of genotype and growing technology was studied on Jerusalem artichoke production characteristics. Totally, 13 clones were used. The harvest of aboveground mass was done in autumn, tubers were harvested in spring (though deep soil freezing, the tubers are not frost-killed). In dependence on year and clone, yields of aboveground part reached 34,2 - 71,9 t FW/ha (12,4 - 24,7 t DW/ha). The yield of spring-harvested tubers ranged between 21,8 and 38,3 t/ha (4,4 - 7,9 t DW/ha). Growing technologies for Jerusalem artichoke were verified, in relation to optimization of cultural practices for obtaining high yields. The most effective fertilization variant was 100 kg N/ha and foliar application of urea, between planting densities no significant differences were recorded for yields. The trials were established to determine soil conservation and ecological function of Jerusalem artichoke crop. On two dates intensive rainfall was simulated on Jerusalem artichoke crop grown on slope. On the first date (July) reduced water runoff and a half soil loss (0,405 t/ha) were found compared to potato crop (0,84 t/ha). On the second date (September), when potato crop is already lodged, the more favourable situation was determined in potatoes compared to Jerusalem artichoke crop. Biogas recovery of aboveground part was studied in two clones, differing in production of aboveground biomass and stem:leaf ratio. Biogas recovery in the sample A was 103-110 m(3)/t FW, corresponding to methan recovery 68-70 m(3)/t FW. Biogas recovery in the sample B was 69-84 m(3)/t FW, corresponding to methan recovery of 41,8-54,5 m(3)/t FW.The results of trials indicated relatively high potential of Jerusalem artichoke in regard to possibilities for non-food use.

The study pert armed between 2004 and 2007 was focused on determination of effect of locally applied and broadcasted mineral N fertilizers on yield and quality parameters under conditions of conventional soil preparation and destoning. For the trial liquid N fertilizer DAM - 390 and solid ammonium sulphate were used at rates of 120 kg N ha(-1) and 80 kg ha(-1). The results obtained in individual years clearly indicate very strong effect of weather progress on all studied parameters. A positive effect of local application of solid mineral N fertilizer was already expressed in study of crop nutritive slate during vegetation. For tuber yield the best results were obtained using of local application of DAM 390 that was included into the trials between 2005 and 2007. Variants of local application of solid mineral fertilizer were also superior to variants of broadcast application in regard to tuber yield. Based on the results of field trials it could be noted, except for 2007, that for local application nitrogen rate in mineral fertilizer could be reduced compared to broadcast application with simultaneous maintaining of tuber yield.

Total anthocyanins (TAC) and individual anthocyanidins (AN) after hydrolysis were measured in 15 red and purple-fleshed potato cultivars produced in five different locations in the Czech Republic and a new cultivar Blaue St. Galler from Switzerland. It was found that TAC, expressed as cyanidin content, varied between 0.7mg 100g−1 FW (cv. Blue Congo) and 74.3mg 100g−1 FW (cv. Blaue Ludiano). Major differences in cultivars were found for AN relative abundance. For cv. Highland Burgundy Red a high proportion of pelargonidin (98.7%) was characteristic, whereas cv. British Columbia Blue contained almost exclusively cyanidin. Cultivars Violette and Vitelotte showed a relatively high content of malvidin. Cultivar Shetland Black differed from others with its higher content of peonidin (on average 36.7%). High petunidin abundance in the cultivars Valfi, Blue Congo, Salad Blue, Blaue St. Galler, Blaue Hindel Bank, Blaue Ludiano, Blaue Schweden, Farbe Kartoffel and Salad Red was found. TAC and AN contents highly corresponded with antioxidant activity (AA) determined with the ABTS, FRAP and DPPH assays in vitro. High AA was shown by the cultivars Vitelotte, Violette, Blaue Ludiano, Hafija, and Highland Burgundy Red. Increased height above sea level, higher annual sum of precipitation, and lower annual average temperatures caused higher AA and TAC. A high degree of hydroxylation and/or methoxylation of individual anthocyanidins could contribute in conjunction with other phenolics to high AA (peonidin, delphinidin and malvidin in the cultivars Blue Congo, Highland Burgundy Red and Shetland Black). Consequently, new red and purple-fleshed cultivars with high TAC and highly methoxylated and/or hydroxylated AN could be a promising source of favourable antioxidants in human nutrition.

Potatoes, members of the Solanaceae plant family, contain calystegines, water-soluble nortropane alkaloids, which are biologically active as glycosidase inhibitors. The content of calystegines A(3) and B(2) in different varieties of potato and in various parts of the tubers (whole potato, peel, flesh, and sprouts) were analysed by new capillary zone electrophoresis and capillary isotachophoresis methods and by the routine GC method. The optimized background electrolyte for capillary zone electrophoretic analysis was mixture of 20 mM histidine, 20 mM N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid and 20% (v/v) methanol in demineralized water. Calystegines were detected by indirect UV detection at 210 nm. A clear separation of calystegines from other components of the methanolic sample extract was achieved within 4 min. The electrolytes for isotachophoretic analysis consisted of 5 mM NH(4)OH, 10 mM N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid, 0.1% hydroxyethylcellulose and 20% (v/v) methanol in demineralized water (leading) and 5 mM histidine+10 mM acetic acid+20% (v/v) methanol in demineralized water (terminating). Calystegines were separated within 20 min and detected by a conductimeter. Method characteristics of both zone electrophoresis and isotachophoresis, i.e., linearity (10-100 ng/microl and 1-10 ng/microl), accuracy (recovery 96+/-5% and 98+/-4%), intra-assay repeatability (4.2% and 3.5%), and detection limit (3 and 0.4 ng/microl) were evaluated. Simple sample preparation, sufficient sensitivity, speed of analysis, and low running cost are important attributes of the electrophoretic methods. The overall results of electrophoretic methods were comparable with GC.

Field trials performed during 2004 - 2007 were focused on the study of weed distribution on selected plots with growing of potatoes. In the period of potato emergence, coordinates were determined for each point in the grid of 20x20 m using of GPS kit GPSMap 276 and values of distribution of all present weed species (g green mass/m(2)) were assigned to the coordinates. From obtained values aggregate maps of weed distribution and also of individual weed species were separately constructed. GPS data were primary processed using of MapSource 5.4 software and maps of weeds were constructed using of mapping software Surfer 8.04 (data interpolation was done by kriging). Results were derived of critical amount of present weed species per area unit in relation to yield reduction. Based on these findings and maps of weed distribution on a concrete field plot data for map construction of treatments (spraying) were designed. The principle consists in determination of critical amount of weed that varies for individual weed species. Over the critical level the treatment is recommended, under the level it is rejected. The map of distribution consists of all "positive" decisions. The treatment is recommended on all points, on that critical amount was exceeded at least in one weed species. The results are maps of recommendation of herbicide application. It was found that it is possible to reduce herbicide usage by 40 % on a plot with generally lower weed distribution with this measure. This procedure has the highest effect in application against locally distributed weeds such as Cirsium arvense and Sonchus arvensis.

The total polyphenol (TP) content in and antioxidant activity of potato tubers of four yellow-fleshed varieties and two purple-fleshed varieties from the 2004 harvest were assayed. The TP content was determined with the Folin-Ciocalteau reagent and antioxidant antiradical activity by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method. Significant differences in the TP content between the groups of yellow-fleshed varieties were found. Significant differences between yellow and purple-fleshed potatoes were also found in antioxidant activity both between yellow and purple-fleshed varieties and within purple-fleshed varieties. The higher potatoes-growing regions showed an apparent tendency to higher TP contents in analyzed varieties. In some varieties the effect of four variants of growing was assayed and a significant effect of high potassium doses (200 and 130 kg K2O per hectare) on the decrease in TP was estimated.

Field trials established in 2004 and 2005 studied effects of growing technology, time of fertilizer application, deposition method, form and rate of fertilizers oil potato yields. Industrial fertilizers containing nitrogen were incorporated during first cultural practices in early spring and immediately prior to planting. Ammonium sulfate - ammonium form (granules) and DAM 390 nitrate, amide and ammonium form (solution) were used for the application. The fertilizers were broadcasted and local incorporated. Special fertilizer applicators were used (for solid and liquid fertilizers). The applicator of solid fertilizer was mounted in the three-point tractor hitch with front hydraulic hitch, integrated with planter. The drive was performed with transfer of torque from the axle using chain drives. The volume of fertilizer rate was regulated by the moving of chain wheels and chain in the system. The applicator of liquid fertilizers was directly mounted oil the potato planter. A 300 l container was fixed ill front three-point hitch. Pump drive was performed through back power take-off Switching oil and off of the applicator was hydraulically controlled together with planter operation. A nozzle was placed at the back of the front plough of the planter in order to apply fertilizer into soil prior to potato seed placement.Local application of 110 kg N/ha at planting brought higher yields only, when liquid fertilizer DAM was applied, nainely ky 12,5 % oil the average qf the years 2004 and 2005 compared to pre-plant broadcasting. Local application of 80 kg N/ha as DAM achieved a 2,5 % higher yield compared to broadcast application of 110 kg N/ha. It is resulted that the efficiency of 80 kg N (local) was comparable to 110 kg N (broadcast). In the case of solid SA fertilizer tuber yields are more favorable due to the year 2005 for broadcast application. Enormous yields were derived due to weather progress (especially in June and July) in 2005. Nitrogen rates between 80 kg N and 110 kg N caused a 10 % increased tuber yields on the average of the years 2004 and 2005.