Potato Tuber Starch Research Articles

Soil Water Stress Effects on Potato Tuber Starch Quality Formation

Soil water stress has a significant impact on crop physiology, however, the specific response of starch quality formation in potato tubers remains unreported. Here, two potato (Solanum tuberosum L.) varieties, one with high, and the other with low tuber starch content, were grown in pots under three different soil water stress treatments, maintaining 75, 50 and 25% of soil field capacity, respectively. Soil water stress restricted potato plant growth and development, and severe stress reduced tuber yield by 47.8% relative to the control. It also inhibited tuber starch biosynthesis, which declined by 62.4% (AGPase activity) relative to the control. Furthermore, water stress reduced tuber starch accumulation by 23.6% (total starch content) relative to the control, and finally, it shortened the tuber starch gelatinization process by 1.44% (pasting temperature) compared to the control. These results reflect the soil water stress regulation mechanism on starch formation and potato tuber quality. Moreover, the study provides a scientific basis for breeding of varieties with high starch content, for improving starch quality and high-efficiency cultivation in dryland potato production.

Qualitative indicator of foreign adapted potato varieties under the influence of fertilizers in the conditions of southeastern Kazakhstan

This paper presents the results of field experiments to study the effect of fertilizers on the quality of potato tubers of the Tien Shan, Gala, Alladin and Innovator varieties grown in the foothill zone of south-east Kazakhstan. The novelty of the research lies in the fact that for the first time in Kazakhstan she is studying the effect of fertilizers on the quality of potato tubers of four varieties grown in the foothill zone of the south-east of the country. The results obtained can be used to develop recommendations for the use of fertilizers for potatoes in this region. The results of the study are consistent with data from similar studies conducted in other regions of Kazakhstan and other countries. It has been established that the application of fertilizers helps to increase the content of dry matter, starch and total sugar in potato tubers. At the same time, the greatest starchiness of the tubers was noted when applying increased doses of mineral fertilizers or the combined use of mineral and organic fertilizers. The nitrate content in potato tubers of the Tien Shan, Gala and Aladdin varieties did not exceed the maximum permissible concentration (MPC - 250 mg/kg). In the tubers of the Innovator variety, the nitrate content was below the maximum permissible concentration, even in the control. Fertilizer application is an effective way to improve the quality of potato crops.

Effect of the use of sweet potato or chayote tuber starch hydrogels on the physical properties of oleogel‐in‐hydrogel (bigels) systems

SummaryBigel systems (BG) were formed through the combination of an oleogel (OG) formed with canola oil and beeswax (5% wt.), and a hydrogel (HG) formed with sweet potato (SP) or chayote tuber (CH) starch (10% wt.), using three OG : HG ratios (30:70, 40:60, 50:50). All the BG were self‐standing, exhibiting uniform and well‐defined phase distribution of OG‐in‐HG, and oil‐binding capacities greater than 96%. Droplet size of BG was influenced by the OG : HG ratio; higher amount of OG produced smaller droplet sizes. The characterisation of BG by FTIR and XRD showed structural configuration in BG is driven by physical and steric interactions by displaying distinctive characteristics of each individual phase and dismissing the formation of novel bonds. BG showed a pseudoplastic behaviour and was characterised as a weak gel, G′ > G″ at strains below 100% for BGSP and 50% for BGCH, with a shifting process (G′ > G″) at higher strains. Viscoelastic properties were influenced by the OG : HG ratio where BG at 50:50 exhibited lower strength and resistance to deformation. Textural parameters in BGSP were higher than BGCH, and influenced by the OG : HG ratio, indicating that the phase proportion in BG can modulate its structure and performance.

Postharvest starch and sugars adjustment in potato tubers of wide-ranging dormancy genotypes subjected to various sprout forcing techniques

The development of an efficient, safe, and environment-friendly technique to terminate tuber dormancy in potatoes (Solanum tuberosum L.) is of great concern due to the immense scope of multiple cropping all over the globe. The breakage of tuber dormancy has been associated with numerous physiological changes, including a decline in the level of starch and an increase in the levels of sugars during storage of freshly harvested seed potatoes, although their consistency across genotypes and various dormancy-breaking techniques have not yet been fully elucidated. The purpose of the present research is to assess the efficacy of four different dormancy-breaking techniques, such as soaking in 90, 60, or 30 mg L−1 solutions of benzyl amino purine (BAP) and 30, 20, or 10 mg L−1 gibberellic acid (GA3) alone and in the combination of optimized concentrations; cold pre-treatment at 6, 4, or 2 °C; electric shock at 80, 60, 40, or 20 Vs; and irradiation at 3.5, 3, 2.5, 2, 1.5, or 1 kGy on the tuber dormancy period and sprout length of six genotypes. Furthermore, the changes that occurred in tuber weight and endogenous starch, sucrose, fructose, and glucose contents in experimental genotypes following the application of these techniques were also examined. Overall, the most effective technique to terminate tuber dormancy and hasten spout growth was the combined application of BAP and GA3, which reduced the length of dormancy by 9.6 days compared to the untreated control, following 6.7 days of electric current, 4.4 days of cold pre-treatment, and finally irradiation (3.3 days). The 60 mg L−1 solution of BAP greatly reduced the dormancy period in all genotypes but did not affect the sprout length at all. The genotypes showed a weak negative correlation (r = − 0.4) (P < 0.05) of endogenous starch contents with dormancy breakage and weight loss or a moderate (r = − 0.5) correlation with sprout length, but a strong positive correlation (r = 0.8) of tuber glucose, fructose, and sucrose contents with dormancy breakage and weight loss. During 3 weeks of storage, sprouting commencement and significant weight loss occurred as tuber dormancy advanced towards breakage due to a reduction in starch and an increase in the sucrose, fructose, and glucose contents of the tubers. These findings could be advantageous for postponing or accelerating seed potato storage as well as investigating related physiological research in the future.

Gradual Analytics of Starch-Interacting Proteins Revealed the Involvement of Starch-Phosphorylating Enzymes during Synthesis of Storage Starch in Potato (Solanum tuberosum L.) Tubers.

The complete mechanism behind starch regulation has not been fully characterized. However, significant progress can be achieved through proteomic approaches. In this work, we aimed to characterize the starch-interacting proteins in potato (Solanum tuberosum L. cv. Desiree) tubers under variable circumstances. Starch-interacting proteins were extracted from developing tubers of wild type and transgenic lines containing antisense inhibition of glucan phosphorylases. Further, proteins were separated by SDS-PAGE and characterized through mass spectrometry. Additionally, starch-interacting proteins were analyzed in potato tubers stored at different temperatures. Most of the proteins strongly interacting with the potato starch granules corresponded to proteins involved in starch metabolism. GWD and PWD, two dikinases associated with starch degradation, were consistently found bound to the starch granules. This indicates that their activity is not only restricted to degradation but is also essential during storage starch synthesis. We confirmed the presence of protease inhibitors interacting with the potato starch surface as previously revealed by other authors. Starch interacting protein profiles of transgenic tubers appeared differently from wild type when tubers were stored under different temperatures, indicating a differential expression in response to changing environmental conditions.

BACILLUS THURINGIENSIS FUNCTIONAL ACTIVITY IN THE NATURAL PHYTOPHAGES ENVIRONMENT (IN THE CONTEXT OF LEPTINOTARSA DECEMLINEATA SAY. POPULATION)

Objective. To evaluate the functional activity of entomopathogenic strains of Bacillus thuringiensis 87 and 800 during bioassay on the target object — the Colorado beetle population depending on the characteristics of bacterial cultivation. Methods. Microscopic, microbiological (to cultivate bacteria on different media and determine the spore titre), bioassay (on the larvae of the natural population of Leptinotarsa decemlineata Say during the period of dominance of the younger age (L1–2), model laboratory and field experiments with potatoes (to determine the degree of entomocidity of the studied strains), weight (to estimate the yield of potatoes during continuous harvesting from plots), biochemical (to determine the content of starch and sugar in potato tubers), statistical. The entomocidal activity of the spore-crystal complex of bacteria was calculated according to Abbott and Franz. Results. The highest productive yield of entomocidal components in liquid presentations of B. thuringiensis occurs on yeast-polysaccharide and cabbage digest media (spore titre ranges from 2.2 to 3.1 billion/mL and 3.6 and 4.7 billion/mL, respectively). According to the entomocidal activity against the larvae of Leptinotarsa decemlineata Say. (L1–4), strains of B. thuringiensis 800 and 87 demonstrated effective parameters from 96.0% and higher at Day 10 of the laboratory experiment. In field conditions, the high functionality of B. thuringiensis 87 (entomocidal activity 95.0–98.0 %), which is not inferior to the chemical variant of spraying potato plants (Koginor, where the death of larvae at Day 7–10 is 96.0–99.0 %). Conclusion. As a result of the conducted research, the efficiency of the use of natural strains of B. thuringiensis 87 and 800 in the formation of potato plant protection systems against phytophages Leptinotarsa decemlineata Say was proven. This confirms high potential of justified application of these strains in agricultural production.

Study of the efficiency of sweet potato growing in the Forest-Steppe of Ukraine by different methods of soil mulching

Sweet potato (Ipomoea batatas L.) is a new crop for soil and climatic conditions of Ukraine, the active implementation of which is hindered by the lack of recommendations on technological aspects of cultivation. One of the important technological measures for growing sweet potatoes is the use of soil mulching, which improves the water regime and regulates the thermal regime of the soil; prevention of weed growth and growth of sweet potato shoots to the soil. Thus, the aim of the research is to determine the efficiency of growing sweet potatoes in the Forest-Steppe of Ukraine by different methods of soil mulching.&#x0D; Field research was carried out on typical low-humus light loamy chernozem on loess loam.&#x0D; It was noted, that when growing sweet potatoes on ridges, the introduction of mulching the soil with black polyethylene film provides more active growth of the vegetative mass throughout the growing season (5.33 shoots/plant with a total length of 252.1 cm), while growing without ridges has a positive effect on plants growth due to the general absence of mulch (2.53 shoots/plant with a total length of 107.8 cm).&#x0D; The use of ridges and mulching the soil with black polyethylene film causes the yield of sweet potato tubers at 34.8 t/ha, while the mulching of the soil with straw, the yield was 18.3–21.9 t/ha, without mulching – 13.0–17, 1 t/ha. Mulching with black polyethylene film ensures the accumulation of vitamin C and starch in sweet potato tubers. When growing the culture on ridges by this method of mulching, the maximum level of vitamin C according to the experiment (4.78 mg/100 g) and starch (11.73 %) was noted.&#x0D; The introduction of mulching and ridge formation involves additional material and labor costs, but helps to reduce weed control and tuber digging costs. When growing sweet potatoes on ridges with mulching with black polyethylene film, the minimum additional labor costs for the formation of a unit of yield (1.95 man-minutes/kg of tubers) were noted, while without mulching and without ridges this figure was 6.76 man-minute/kg

Respon dua genotip kentang (Solanum tuberosum L.) dengan pemberian tiga sumber pupuk nitrogen di dataran medium

This study aimed to evaluate the growth and yield of two potato genotypes (S) due to three sources of nitrogen (G) fertilizer on medium plains. The study was arranged in a two-factor, randomized block design factorial and was repeated three times. The first factor is the source of N fertilizer, consisting of three levels: S1 = ZA ((NH4)2SO4), S2 = urea (CO(NH2)2), and S3 = ammonium nitrate (NH4NO3). The second factor was potato genotype, consisting of two levels G1 = MS 13 genotype and G2 = At 4 genotype. The data obtained were analyzed by F test at 5% level (ANOVA) to determine the effect of treatment and further LSD test was carried out to determine differences between treatments, and multiple regression analysis to determine the most influential factors on potato tuber starch content. The results showed that the highest starch content was obtained by the At 4 genotype of 18,50% and was suitable for medium plains. While the starch content of the MS 13 genotype was 17,53%. For fertilizing nitrogen sources, it is recommended to use ammonium nitrate, because it obtains the highest yield of 27,30 tons ha-1 from other nitrogen fertilizer sources.&#x0D; &#x0D;

Changes in dry weight and starch content in potato under the effect of herbicides and biostimulants

The aim of the study was to determine the interaction of herbicides and herbicides with biostimulants on the accumulation of dry matter and starch in potato tubers. In a three-year field experiment based on the method of randomised sub-blocks, two factors were taken into account. The first factor were potato cultivars: Bartek, Gawin, Honorata. The second factor were five methods of herbicides and biostimulants application: (1) the control object without chemical protection (CO); (2) herbicide linuron + clomazone (Harrier 295 ZC) (H); (3) herbicide linuron + clomazone (Harrier 295 ZC) and biostimulant Ecklonia maxima (Kelpak SL) – (H + K); (4) herbicide metribuzin (Sencor 70 WG) – (S); (5) herbicide metribuzin (Sencor 70 WG) and biostimulant sodium para-nitrophenol, sodium ortho-nitrophenol, sodium 5-nitroguaiacol (Asahi SL) – (S + A). The cultivars and weather conditions significantly affected the content and yields of dry matter and starch. The herbicides and biostimulants used determined the starch accumulation as well as dry matter and starch yields. Most starch in tubers (more by 3.7 g/kg) and the highest dry matter and starch yields (more by 2.87 and 1.79 t/ha, respectively), compared to the control object, were obtained after the application of the herbicide Sencor 70 WG and biostimulant Asahi SL.

Ratio of starch, protein, and glycoalkaloids in potato tubers during the growing season

Ratio of starch, protein, and glycoalkaloids in potato tubers during the growing season

Acid Hydrolysis‐Induced Nanoconversion of Sweet Potato (Ipomoea Batatas) Starch: Effect on Morphological, Rheological, and Thermal Properties

AbstractThe present study aims to prepare starch nanocrystals (SNCs) from sweet potato tuber starch and study their morphological, crystalline, rheological, and thermal properties. The platelet‐like SNCs are obtained using acid hydrolysis of round or polygonal native sweet potato starch granules. The average hydrodynamic diameter of SNCs is 184 nm as measured using the dynamic light scattering technique. The polydispersity index value based upon molecular weight distribution as determined using gel permeation chromatography increases from 1.386 for native starch (NS) to 2.958 for SNCs, indicating the heterogenous molecular weight distribution of acid hydrolyzed starch. The zero value of the radius of gyration for nanocrystals indicates the formation of anisotropic platelet‐like SNCs. The gelatinization temperature and melting enthalpy significantly increased after the nanoconversion of starch granules; thus, SNC's thermal properties are improved after acid hydrolysis of NS. The SNCs exhibit shear‐thinning behavior (lower viscosity) at high concentrations; the visco‐elastic behavior of SNCs dispersions is frequency‐dependent, with elastic character prevalence over viscous at lower frequencies.

Iodine Biofortification of Potato (Solanum tuberosum L.) Grown in Field

Despite wide prevention programmes, iodine deficiency remains a substantial problem in various populations around the world. Consumption of crop plants with increased iodine content may help supply additional amounts of that element in a daily diet. The aim of the work was to evaluate the efficiency of iodine biofortification of potato tubers. Soil application of KI and foliar application of KIO3 in doses up to 2.0 kg I ha−1 were tested in a three-year field experiment. Biomass, yield as well as dry matter, iodine, starch, and soluble sugar content in potato tubers were analyzed. No negative effect of tested methods of iodine application on potato yield or dry matter content was observed. Both soil and foliar application of iodine allowed to obtain potato tubers with increased content of that element with no decrease of starch or sugar content. The highest efficiency of iodine biofortification was noted for foliar spraying with KIO3 in a dose of 2.0 kg I ha−1. The obtained level of iodine in 100 g of potatoes could be sufficient to cover up to 25% of Recommended Daily Allowance for that element. The findings of the study indicate that potatoes biofortified with iodine can become an additional source of I in a daily diet.

Genetic loci determining potato starch yield and granule morphology revealed by genome-wide association study (GWAS).

BackgroundIt is well-documented that (bio)chemical reaction capacity of raw potato starch depends on crystallinity, morphology and other chemical and physical properties of starch granules, and these properties are closely related to gene functions. Preparative yield, amylose/amylopectin content, and phosphorylation of potato tuber starch are starch-related traits studied at the genetic level. In this paper, we perform a genome-wide association study using a 22K SNP potato array to identify for the first time genomic regions associated with starch granule morphology and to increase number of known genome loci associated with potato starch yield.MethodsA set of 90 potato (Solanum tuberosum L.) varieties from the ICG “GenAgro” collection (Novosibirsk, Russia) was harvested, 90 samples of raw tuber starch were obtained, and DNA samples were isolated from the skin of the tubers. Morphology of potato tuber starch granules was evaluated by optical microscopy and subsequent computer image analysis. A set of 15,214 scorable SNPs was used for the genome-wide analysis. In total, 53 SNPs were found to be significantly associated with potato starch morphology traits (aspect ratio, roundness, circularity, and the first bicomponent) and starch yield-related traits.ResultsA total of 53 novel SNPs was identified on potato chromosomes 1, 2, 4, 5, 6, 7, 9, 11 and 12; these SNPs are associated with tuber starch preparative yield and granule morphology. Eight SNPs are situated close to each other on the chromosome 1 and 19 SNPs—on the chromosome 2, forming two DNA regions—potential QTLs, regulating aspect ratio and roundness of the starch granules. Thirty-seven of 53 SNPs are located in protein-coding regions. There are indications that granule shape may depend on starch phosphorylation processes. The GWD gene, which is known to regulate starch phosphorylation—dephosphorylation, participates in the regulation of a number of morphological traits, rather than one specific trait. Some significant SNPs are associated with membrane and plastid proteins, as well as DNA transcription and binding regulators. Other SNPs are related to low-molecular-weight metabolite synthesis, and may be associated with flavonoid biosynthesis and circadian rhythm-related metabolic processes. The preparative yield of tuber starch is a polygenic trait that is associated with a number of SNPs from various regions and chromosomes in the potato genome.

Влияние новых удобрений на урожайность и качество картофеля

Одним из методов совершенствования технологии возделывания картофеля является применение комплексных водорастворимых хелатных удобрений. В 2018 – 2019 гг. исследовано воздействие комплексного минерального удобрения Грин-Го 18 – 18 – 18 + 1,3MgO + микро и микроудобрения Рексолин ABC на рост и развитие районированных по Северо-Западному региону РФ сортов картофеля с различными сроками созревания. В опыте исследовали 9 сортов по 3 группам скороспелости: раннеспелые — Чароит (очень ранний), Удача, Ред Скарлет; среднеранние — Гала, Елизавета, Памяти Осиповой; среднеспелые — Аврора, Каскад, Ладожский. Обрабатывали удобрениями в 2 этапа: предпосадочная обработка клубней водным раствором препарата Рексолин ABC и внесение Грин-Го 18 – 18 – 18 + 1,3MgO + микро по достижении всходов 10 см. Определяли урожайность клубней картофеля, содержание в них сухого вещества, крахмала и нитратов. Выявлено положительное влияние применяемых удобрений на урожайность и качество исследуемых сортов картофеля. Все исследуемые сорта по содержанию нитратов не превышали предельно допустимой концентрации (250 мг/кг), которая варьировала в пределах 96–106 мг/кг. Лучшие показатели по урожайности отмечены у группы раннеспелых и среднеранних сортов — превышение по сравнению с контролем (без обработки) составило 16,5 – 66,5 % в 1-й год исследований и 12,1 – 71,0 % во 2-й год. Выявлено повышение содержания крахмала и сухого вещества в клубнях картофеля при применении удобрений — соответственно до 12,1 – 16,7 и 21,3 – 26,8 %. Опытные среднеспелые сорта не показали значительных результатов по урожайности, что может быть связано со сроками внесения и концентрацией используемых препаратов.

Biochemical changes in affected potato tubers

Goal. To establish biochemical changes (contents of dry matter, vitamin C, starch and carotene) in potato tubers in different degree affected by fungal diseases.&#x0D; Methods. Potato tubers (variety Bella Rosa) was selected in the conditions of private sector, Brusilovsky district, Zhytomyr region. Diagnosed disease by the visual method and a microscopic analysis with the subsequent identification of the pathogens. Biochemical analysis of potato tubers on dry matter content, vitamin C, starch, and carotene were performed according to standard techniques of the Institute of potato NAAS.&#x0D; The results of the research. The result of phytopathological examination of potato tubers during storage revealed fungal diseases: rot, Fusarium dry, Pomona, white, grey and verticillata; scab — plain and black or black scurf. Is established, that biochemical parameters in potatoes with different degree of damage differed. The amount of solids in healthy potato tubers were 21.0% in severely infected by Fusarium 14.5%, and famosa 13.9% and the usual scab — 18.2%; the blight of 15.6%. Starch in healthy tubers was 15.4% strongly struck by Fusarium is 7.5%, famosa — 6.9%, the usual scab — 11.2%, a Rhizoctonia — 9.8%. The content of vitamin C in healthy tubers was 0.17 percent, and in severe cases, Fusarium and 0.12%, famosa — 0.12%, ordinary scab and 0.12%, a Rhizoctonia — 0.12%. Biochemical indicators of carotene in healthy tubers was 0.18%, and in severely infected by Fusarium was reduced to 0.09%, famosa up to 0.06%, the usual scab — up to 0.11%, a Rhizoctonia — up to 0.10%.&#x0D; Conclusions. In potato tubers with different degrees of lesions of fungal diseases of reduced the content of dry matter, starch, vitamin C and carotene, which worsens their quality.

ОСНОВНЫЕ РЕЗУЛЬТАТЫ ИЗУЧЕНИЯ СОРТОВ КАРТОФЕЛЯ СТОЛОВОГО НАЗНАЧЕНИЯ В ОРЕНБУРЖЬЕ

The research aim is identification of promising varieties that provide the highest productivity and adaptability to soil and climatic conditions of the Orenburg Region. Nowadays, the introduction of new table varieties into production, capable of resisting the influence of unfavorable abiotic and biotic environmental factors, will make it possible to better meet the population's need for high-quality potatoes. In 2016-2018 In the irrigated conditions of Orenburg, a comparative test of eighteen potato varieties was carried out (Lyubava, Kuzovok, Red Scarlett, Burren, Barna, Nev-sky, Fresco, Spiridon, Tarasov, Sante, Impala, Sherry, Rosara, Zakhar, Agat, Itzil, Cavalier, Bracelet). The experi-ment was laid on the basis of OOO Agrofirma Promyshlennaya, the soil cover of the plot is the southern terraced chernozem medium medium humid medium soil. Annually fertilizer was applied with a dose of N75P120K112 kg d.v. The experience was laid on a single-factor scheme in 3 replicates. Plot area 140 m2 (50 m × 2.8 m), accounting – 70 m2 &#x0D; (50 m × 1.4 m). The yield, marketability, starch and dry matter content in potato tubers were determined. Years of research differed in climatic characteristics, which made it possible to reliably assess the possibilities of the varie-ties under study. As a result of three years of research, the maximum productivity of 46.5 and 44.8 t/ha was ob-served in the Cavalier and Barna varieties, which exceeded the yield of the standard Nevsky variety by 42 and 45 %, respectively. The maximum number of tubers from one plant was obtained from the varieties Lyubava (15 pcs/bush) and Barna (12 pcs/bush). The most adaptive to local conditions varieties of potato were distinguished, combining high yields over 40 t/ha and starch content (&gt; 14 %): Cavalier, Lubawa, Tarasov and Burren.&#x0D; The studies were carried out in accordance with the research plan for 2019-2020 Federal State Scientific Institution «Federal Research Centre of Biological Systems and Agro-technologies of the Russian Academy of Sciences» &#x0D; (№ 0761-2019-0011).

ПОДБОР СРЕДНЕРАННИХ И СРЕДНЕСПЕЛЫХ СОРТОВ КАРТОФЕЛЯ ДЛЯ СТЕПНОЙ ЗОНЫ ЮЖНОГО УРАЛА

The purpose of research is to identify the most adaptive and productive varieties of potatoes for the steppe zone of Southern Urals. The experience was laid by one-factor circuit in 3-fold repetition. The studies were conducted for middle- and middle-early varieties of potatoes domestic and foreign selection. Determined yield, marketability, starch and dry content in potato tubers. At 4 years of data were allocated potato varieties – Artemis (57.8 t/ha), Aerrow (52.0 t/ha) and Romano (49.5 t/ha). Distinguished highest yield of marketable products varieties: Artemis – 97.9%, Tarasov – 97.7%, and Aerrow Romano – 97.4%. The starch content in tubers was measurable by 10.2% (Ed Scarlett) to 16.0% (Kovalenko Memory), and the dry matter content in tubers ranged from 15.6% (Ed Scarlett) to 23.8% (Memory Kovalenko).

Potato performance as influenced by the proportion of wetted soil volume and nitrogen under drip irrigation with plastic mulch

Scarce water resources and substantial food demands require efficient water use in arid Northwestern China. Field experiments were conducted to investigate the effects of the proportion of wetted soil (P) and nitrogen fertilizer (N) on potato yield, crop evapotranspiration (ETc), water use efficiency (WUE), and quality under drip irrigation with plastic mulch. In 2012, a factorial trial was conducted with two soil wetting proportions (40% and 70%) and five N rates (90, 135, 180, 225 and 270kgNha−1). In 2013, a factorial trial tested two soil wetting proportions (50% and 75%) and four N rates (90, 150, 210 and 270kgNha−1). Results showed that seasonal ETc was greater with higher P, but the difference in ETc was not significant among different N rates. Although tuber yields of different P levels were not statistically different, yields with lower P were numerically larger than with higher P. The water was used more efficiently with lower proportions of wetted soil. Potato yield, WUE, and tuber starch and vitamin C content responded quadratically to the rate of applied N. Tuber protein was positively and linearly correlated with the N rate. The results suggest that potato could be cultivated with a moderate P (40–50%) and an intermediate rate of applied N (135–150kgNha−1) under drip irrigation with mulch, achieving acceptable yields and quality while saving irrigation water and conserving N fertilizer.

Efekti stosowania nawozow kompleksowych w uprawie ziemniaka na wczesny zbior na glebie piaszczysto-gliniastej

To obtain a high tuber yield of early crop potato good conditions for plant growth must be ensured. Potato has a relatively shallow root system and requires significant nutrient inputs to maintain tuber productivity and quality. The paper presents the results of the research on the effect of complex fertilizers type NPK MgS with and without microelements from the nitrophoska (HydroComplex, Nitrophoska Blue Special and Viking 13) and the amophoska group (Polimag S), and single-nutrient fertilizers on the plant growth and tuber yield of very early potato cultivars (‘Aster’, ‘Fresco’, ‘Gloria’) on loamy sand soil. The field experiment was carried out in mideastern Poland (52°03'N, 22°33'E). Potatoes were harvested 75 days after planting (the end of June). The type of fertilizer (single-nutrient or complex fertilizer) slightly affected the growth of potato plants. With the use of complex fertilizers, the assimilation leaf area and leaf area index (LAI) were similar to the application of single-nutrient fertilizers. Of the examined complex fertilizers, Viking 13 (representing the nitrophoska group without microelements) resulted in a smaller increase of assimilation leaf area in comparison with the cultivation without mineral fertilization. The type of fertilizer exerted a greater influence on the plant growth of ‘Aster’ (Poland) than ‘Fresco’ (The Netherlands) and ‘Gloria’ (Germany). The productive effects of complex fertilizers in early crop potato culture on loamy sand soil were comparable with single-nutrient fertilizers. The highest tuber yield was achieved with the application of Nitrophoska Blue Special (from the nitrophoska group with the lowest NNH4+ concentration); the total tuber yield was higher on average by 2.94 t*ha-1 (21.0%) and the yield of marketable tuber fraction (diameter above 30 mm) by 2.55 t*ha-1 (20.4%) in comparison with the cultivation without mineral fertilization. Although the total tuber yield was a little lower, the share of large tubers (diameter above 51 mm) in the yield was recorded with the use of Polimag S (from the amophoska group and with the most Mg, S, Zn and B concentration of all complex fertilizers applied) and Viking 13 (from the nitrophoska group with Ca). The single-nutrient and complex fertilizers applied in the experiment had no effect on the dry matter, starch or Lascorbic acid content in potato tubers. Regardless of the type of fertilizer applied, the tuber yield, average weight of one tuber and the share of medium-sized tubers (diameter of 4150 mm) in the yield of ‘Aster’ were highest. The yield of marketable tuber fraction of the ‘Aster’ was higher than ‘Fresco’ and ‘Gloria’ on average by 3.03 t*ha-1 (22.0%) and 4.57 t*ha-1 (37.4%), respectively. About 25% of the ‘Gloria’ yield made up of non-marketable tubers (diameter below 30 mm). Tubers of ‘Aster’ contained more dry matter and starch than ‘Fresco’ and ‘Gloria’, however, the content of Lascorbic acid in tubers of the tested potato cultivars was similar.

Phosphorylation of transitory starch by α‐glucan, water dikinase during starch turnover affects the surface properties and morphology of starch granules

Glucan, water dikinase (GWD) is a key enzyme of starch metabolism but the physico-chemical properties of starches isolated from GWD-deficient plants and their implications for starch metabolism have so far not been described. Transgenic Arabidopsis thaliana plants with reduced or no GWD activity were used to investigate the properties of starch granules. In addition, using various in vitro assays, the action of recombinant GWD, β-amylase, isoamylase and starch synthase 1 on the surface of native starch granules was analysed. The internal structure of granules isolated from GWD mutant plants is unaffected, as thermal stability, allomorph, chain length distribution and density of starch granules were similar to wild-type. However, short glucan chain residues located at the granule surface dominate in starches of transgenic plants and impede GWD activity. A similarly reduced rate of phosphorylation by GWD was also observed in potato tuber starch fractions that differ in the proportion of accessible glucan chain residues at the granule surface. A model is proposed to explain the characteristic morphology of starch granules observed in GWD transgenic plants. The model postulates that the occupancy rate of single glucan chains at the granule surface limits accessibility to starch-related enzymes.