Impact of Agronomic Strategies (Seed Tuber Pre-sprouting,Cultivar Choice) to Control Late Blight (<Emphasis Type="Italic">Phytophthora infestans</Emphasis>) on Tuber Growth and Yield in Organic Potato (<Emphasis Type="Italic">Solanum tuberosum</Emphasis> L.) Crops

In order to optimize potato crop management in organic farming systems, knowledge of crop growth processes in relation to limitations and reductions by nitrogen (N) and disease is necessary. This paper examines the effect of different prevention measures (seed tuber pre-sprouting, choice of cultivars: resistance to Phytophthora infestans; earliness of tuber initiation) against disease-related constraints on yields, depending on the N-mediated growing conditions of organic potato crops. Under conditions of a relatively high N supply, accelerating the early development and tuber initiation of potato crops by seed tuber pre-sprouting (yield increase of c. 18–23%) or the selective choice of cultivars with an earlier tuber initiation (yield increase of c. 0–21%) are the most effective strategies in combating late blight. They bring forward the crop development c. 7–10 days, escaping the negative impact of the fungus on tuber growth. Under conditions of a relatively low N supply, these strategies do not affect final tuber yield. The reason for the differences of the effect depending on N supply of the crops is, that the lower the N supply, the shorter the period of time over which tuber growth takes place, independent of whether P. infestans becomes severe or not. Tuber growth of organic crops low in N has mostly ceased by the time late blight becomes potentially important for limiting yield, with the consequence that preventative measures against P. infestans are meaningless. Surprisingly, the level of cultivar haulm resistance to late blight did not affect tuber yields in years with an early and strong late blight development. Probably, the positive effect of a longer resistance to the fungus (c. 1 week) was counterbalanced by a later tuber initiation (also c. 1 week). In years with a moderate late blight incidence, less susceptible cultivars were able to produce higher tuber yields on fields with a lower N availability (c. 17–20%), probably due to higher N use efficiency and a better match of N mineralization and N uptake. Under conditions of a relatively high N supply, the tested cultivars with a higher haulm resistance to late blight were not able to improve tuber yields.     

Resistance to <Emphasis Type="Italic">Potato virus Y</Emphasis> in a Multitrait Potato Breeding Scheme without Direct Selection in Each Generation

In an experimental breeding scheme to improve late blight (Phytophthora infestans) and white potato cyst nematode (Globodera pallida) resistance of tetraploid potato over three generations of crossing and selection, 15 clones survived the final selection, and these were derived from 15 great-grandparents. There was no direct selection for resistance to Potato virus Y (PVY), but 14 out of the 15 great-grandparents were resistant to PVY and three had extreme resistance. Thirteen of the 15 descendants had PVY resistance and one extreme resistance. This was within the range expected for a random (unselected) sample from the genotypes of the great-grandparents. Hence, we found no evidence for any positive or negative association between PVY resistance and the attributes selected. The conclusion is that laborious selection is not required in every generation when many parents have PVY resistance, including some with more than one copy of a PVY resistance gene or resistance at more than one locus. However, in the future, determining the major virus resistance genes present in potential parents in each generation using diagnostic molecular markers would prevent susceptible × susceptible crosses being made and maximise the number of resistant × resistant ones.     

Maturity-Adjusted Resistance of Potato (<Emphasis Type="Italic">Solanum tuberosum</Emphasis> L.) Cultivars to Verticillium Wilt Caused by <Emphasis Type="Italic">Verticillium dahliae</Emphasis>

Verticillium wilt is a fungal disease of potato caused by two species of Verticillium, V. dahliae and V. albo atrum. The pathogen infects the vascular tissue of potato plants through roots, interfering with the transport of water and nutrition, and reducing both the yield and quality of tubers. We have evaluated the reaction of 283 potato clones (274 cultivars and nine breeding selections) to inoculation with V. dahliae under greenhouse conditions. A significant linear correlation (r = 0.4, p < 0.0001) was detected between plant maturity and partial resistance to the pathogen, with late maturing clones being generally more resistant. Maturity-adjusted resistance, that takes into consideration both plant maturity and resistance, was calculated from residuals of the linear regression between the two traits. Even after adjusting for maturity, the difference in the resistance of clones was still highly significant, indicating that a substantial part of resistance cannot be explained by the effect of maturity. The highest maturity-adjusted resistance was found in the cv. Navajo, while the most susceptible clone was the cv. Pungo. We hope that the present abundance of data about the resistance and maturity of 283 clones will help potato breeders to develop cultivars with improved resistance to V. dahliae.     

Preparation and application of an<Emphasis Type="Italic">s</Emphasis>-triazine-based novel<Emphasis Type="Italic">N</Emphasis>-halamine biocide for antimicrobial fibers

N-halamines serve as important antimicrobial agents. Development of this class of compounds has been shown to provide benefits especially from a biocidal point of view. A novels-triazine-basedN-heterocycle, dichloro-m-aminophenyl-hydantoinyl-s-triazine (DAPHT), which could be rendered antimicrobial through exposure to diluted chlorine bleach, was synthesized and characterized by¹H NMR,¹³C NMR, and FT-IR. A finishing method was used to apply theN-halamine precursor onto cotton fabric, and the optimum conditions for finishing were investigated. The DAPHT-treated cotton fabric had durable antimicrobial properties up to 50 standard washing cycles and was rechargeable under normal laundry/bleaching conditions. The antimicrobial efficacy against Gram-positive and Gram-negative bacteria was demonstrated.     

Nitrogen and Phosphorus Use Efficiency in Improved Potato (<Emphasis Type="Italic">Solanum tuberosum</Emphasis> L.) Cultivars in Southern Ethiopia

Use of nutrient efficient crop species or cultivars within species in combination with improved crop production practices offer the best option for meeting the future food requirements of growing world populations. Efficiency improvement has a key role for nutrient use and it improves both productivity of yield and minimizes risks of losses that potentially harm the environment. To improve nutrient use efficiency (NUE), one strategy is to select cultivars of crops with high NUE. Both nitrogen (N) and phosphorus (P) are among essential macronutrients commonly applied to agricultural crops to optimize yields. Evaluation of potato cultivars with high N and P efficiency is essential for sustainable production of the crop. In Ethiopia, however, little research has been done to elucidate better NUE of potato crop until recently. This study was, thus, designed to evaluate selected potato cultivars (Belete, Gudene, Jalene, Marachere and one local check) for NP use efficiency under low levels of the nutrients in Wolaita Sodo University, Ethiopia during 2014 and 2015. Factorial combination of 3 levels of each N (0, 55.5 and 111 kg N ha^?1 ) and P (0, 19.5 and 39 kg P ha^?1 ) were assigned to the main plots and the 5 cultivars to subplots of split-plot design in three replications. Efficiency indices such as agronomic efficiency, physiological efficiency and recovery efficiency were computed for combined NP nutrients. Results showed that agronomic nitrogen use efficiency, apparent phosphorus use efficiency and phosphorus use efficiencies were significantly influenced by the interaction effect of rates of NP nutrition and variety. Application of NP more than 55.5:19.5 kg ha^?1 will not beneficial due to their less or equal use and recovery efficiencies to 55.5:19.5 kg NP ha^?1. Belete was the most NP efficient variety followed by Jalene and Gudene in all efficiency indices. Therefore, Belete, Jalene and Gudene return better for NP at 55.5:19.5 kg ha^?1 for economical use of fertilizes while obtaining satisfactory yield. It can be concluded that yield response variation of the varieties was related to their differences in NP uptake and use efficiencies; and the improved potato varieties were superior to local check in using NP nutrients efficiently.     

Antioxidant in Mango (<Emphasis Type="Italic">Mangifera indica</Emphasis> L.) Pulp

This work was carried out to investigate the pulp composition of four mango cultivars (Haden, Tommy Atkins and Ubá) at the ripening stage in relation to three components with antioxidant potential (total phenolics, carotenoids and ascorbic acid). Total phenolic compound content was estimated by the Folin-Ciocalteu reagent and total carotenoid content by spectrophotometry at 450 nm. The contents of β-carotene and total vitamin C (ascorbic acid and dehydroascorbic acid) were quantified by high performance liquid chromatography. Differences were found among the four mango cultivars in all the components analyzed. The content of phenolic compounds ranged from 48.40 (Haden) to 208.70 mg/100 g (Ubá); total carotenoid from 1.91 (Haden) to 2.63 mg/100 g (Palmer); β-carotene from 661.27 (Palmer) to 2,220 μg/100 g (Ubá) and total ascorbic acid ranged from 9.79 (Tommy Atkins) to 77.71 mg/100 g (Ubá). These results corroborated previous information that mangoes are a good source of antioxidants in human diet.     

Genetic Diversity and Core Collection for Potato (<Emphasis Type="BoldItalic">Solanum tuberosum</Emphasis> L.) Cultivars from Cameroon as Revealed by SSR Markers

Twelve pairs of SSR markers were used to evaluate the genetic diversity of 138 accessions of potato cultivars from the Western Highlands region of Cameroon. The average Polymorphism information content (PIC) value (0.74) and number of alleles (7.08) indicated a high genetic diversity of the potato cultivars tested. Analysis of molecular variance revealed that most of the genetic variations are found within geographic region (≥ 91%), resulting in high gene flow (Nm > 4 individuals). Local varieties had significantly more alleles than exotic varieties. Genetic diversity estimates for accessions from low elevations were significantly lower than those from medium and high elevations. Cluster analysis showed three clusters; the model-based approach inferred two gene pools. Genotypes revealed a high level of admixture between gene pools within locations and elevations. A core collection identified in this study composed of 27 individuals representing 19.57% of the whole collection and captured 99.15% of the total alleles found.     

Predictive Markers for Cold-Induced Sweetening Resistance in Cold Stored Potatoes (<Emphasis Type="Italic">Solanum tuberosum</Emphasis> L.)

An approach has been developed to screen a large number of potato clones for cold induced sweetening (CIS) resistance in breeding programs. Two key enzymes responsible for reducing sugar accumulation during cold storage were identified. Clones with the A-II isozymes of UDP-glucose pyrophosphorylase coupled with low activity of vacuolar acid invertase enzyme had increased resistance to CIS by forming less suc, which is subsequently hydrolyzed to the undesirable reducing sugars, glc and fru. Six named cultivars and 192 genetically diverse clones from various breeding programs in USA were analyzed over two years for the two key enzymes and sugar concentration in cold stored tubers. The predictability for CIS resistance during cold storage was 94% both years. Clones classified as class A accumulated low concentration of reducing sugar glc during cold storage. It is suggested that these two predictor enzymes can be used for screening parents and selections in potato breeding program.     

Antifungal textile dyeing with<Emphasis Type="Italic">Mahonia napaulensis D.C.</Emphasis> leaves extract based on its antifungal activity

The antifungal activity of the methanolic extract ofMahonia napaulensis D.C. or Taming (local name) leaves was evaluated with four species of common pathogenic fungi e.g.Colletotrichum capsici (MTCC No. 2071),Leptosphaerulin trifoli (MTCC No. 2328),Alternaria brassicicola (MTCC No. 2102) andHelminthosporium solani (MTCC No. 2075). The present investigation also aims at developing an eco friendly natural antifungal finish from plant extract ofMahonia for textile application. The antifungal textile dyeing was also carried out with aqueous extract of stem and leaves ofMahonia and the dyed fabric was tested against fungal speciesTrichoderma for its antifungal activity in vitro.Mahonia extract showed substantial antifungal activity of 83.33% forLeptosphaerulin trifoli andAlternaria brassicicola by 80 ppm dose in 24 hours and 46% antifungal activity inMahonia dyed pieces in broth againstTrichoderma.     

Performance of Dimethomorph + Mancozeb Applied to Seed Potatoes in Early Management of Late Blight (<Emphasis Type="Italic">Phytophthora infestans</Emphasis>)

Treating seed potatoes with contact fungicides prevents infection of Phytophthora infestans from tuber to tuber during handling but does not prevent field infections in the young plant. Dimethomorph (DMM) 9% + mancozeb 60% (Acrobat MZ, BASF) can cover both aspects due to the contact and systemic action of mancozeb and DMM, respectively. Experiments were performed under greenhouse and field conditions (three seasons and two locations) with cvs Kennebec, Shepody, Spunta, Russet Burbank, and Ranger Russet. Immediately after cutting, seed pieces were treated with Acrobat MZ at doses equivalent to 2, 3, and 4 kg ha⁻¹. At any dose, Acrobat MZ protected healthy seed tubers against P. infestans infections. Acrobat MZ (4 kg ha⁻¹) also protected the foliage of all cultivars against artificial inoculation of P. infestans, assessed by the detached-leaf method. These effects were observed up to 30 days after emergence in greenhouse experiments and up to 28 days after crop emergence under field conditions in two growing seasons. In cv Spunta, significant foliage protection was observed up to 35 days after field emergence whereas in seed tubers of cv Kennebec planted in sandy soils, significant foliage protection persisted longer. Additional evidence for acropetal translocation of Acrobat MZ in field crops was also found. With this strategy, there is no need to apply contact or systemic fungicides early in the season, and spraying costs and environmental risks are also reduced.     

Detection of Glycoalkaloids and Chlorophyll in Potatoes (<Emphasis Type="Italic">Solanum tuberosum</Emphasis> L.) by Hyperspectral Imaging

The purpose of the study was to investigate the use of hyperspectral imaging (HSI) to detect and quantify chlorophyll (Chl) and total glycoalkaloid concentrations (TGA) in potatoes. To create a set of tubers with different concentrations of Chl and TGA, potatoes of four varieties were wounded or treated with red, blue, red/blue, UV-a, UV-b or UV-c light. HSI analyses were performed with a reflection based setup implemented in an industrial potato sorting machine. After hyperspectral analyses, the peel was sampled, and concentrations of Chl and total TGA were determined. Results showed that the HSI system predicted the concentrations of Chl with a relatively high degree of accuracy, and a prediction R² value of 0.92. Prediction of TGA concentrations performed to a much lesser extent, and the overall prediction R² value was only 0.21. Moderate soil covers only affected the prediction powers to a minor degree.     

Antioxidant and Antifungal Activity of <Emphasis Type="Italic">Verbena officinalis</Emphasis> L. Leaves

The scavenging activity against DPPH (1,1-diphenil-2-picrylhydrazyl) radical and the antifungal effect against chloroform, ethyl acetate and 50% methanolic extracts of Verbena officinalis leaves were investigated. The activity of different fractions of 50% methanolic extract and some isolated compounds were also investigated. The results suggest that 50% methanolic extract and caffeoyl derivatives could potentially be considered as excellent and readily available sources of natural antifungal and antioxidant compounds.     

Antioxidative and Anticancer Activity of Extracts of Cherry (<Emphasis Type="Italic">Prunus serrulata</Emphasis> var. <Emphasis Type="Italic">spontanea</Emphasis>) Blossoms

Organic solvent (methanol, ethanol, and acetone) extracts and water extracts of cherry (Prunus serrulata var. spontanea) blossoms were prepared, and antioxidant activities of the extracts were evaluated. Methanolic CBE (100 μg/ml) showed the highest total phenol content (104.30 μM), radical scavenging activity (34.2%), and reducing power (0.391). The effect of CBE on DNA damage induced by H₂O₂ in human leukocytes was evaluated by Comet assay. All CBE was a potent dose dependent inhibitor of DNA damage induced by 200 μM of H₂O₂, methanolic CBE showed the most strong inhibition activity. The methanolic CBE of 500 μg/ml showed 38.8% inhibition against growth of human colon cancer cell line HT-29. These results indicated that cherry blossoms could provide valuable bioactive materials.     

Dyeing of cotton and silk yarn with the extracted dye from the fruit hulls of mangosteen,<Emphasis Type="Italic">Garcinia mangostana</Emphasis> linn

The extracted dye from the dried fruit hulls of mangosteen was used as a natural dye for the dyeing of cotton and silk yarn. The optimal conditions for dye extraction were to extract the dried fruit hulls of mangosteen at 80°C for 1 hour with a 15 % w/v citric acid solution in a 1:4 ratio of mangosteen powder to solvent. Cotton dyeing with the extracted dye from the dried fruit hulls of mangosteen was carried out at 60°C for 60 minutes with a material to liquor ratio of 1:25. The effect on dyeing of mordant type with different mordanting methods was studied. The results showed that the dyeing of cotton using the post-mordanting method with ferrous sulfate and calcium hydroxide not only provided better depth of shade but also provided better wash fastness and light fastness than with other mordants (alum; zinc tetrafluoroborate) or without a mordant. Good fastness properties were also obtained using a post-mordanted silk with calcium hydroxide.     

Applied Biotechnology to Combat Late Blight in Potato Caused by <Emphasis Type="Italic">Phytophthora Infestans</Emphasis>

Potato is an important crop, grown worldwide. It suffers from many pests and diseases among which late blight, caused by the oomycete Phytophthora infestans, is the worst. The disease is still causing major damage in many potato production areas and control is only possible by applying fungicides frequently. The knowledge on the molecular biology and genetics of the interaction between the plant and the oomycete is developing rapidly. These are relevant fields of study, currently dominated by the discovery of many resistance genes and numerous effector proteins and the analysis of their specific mode of action. These studies may yield essential information needed for the development of durable resistance. The long-term and worldwide effort to breed for resistance so far has had little effect. A novel breeding approach may change this. It is based on cisgenic modification (CM) consisting of marker-free pyramiding of several resistance genes and their spatial and temporal deployment yielding dynamic varieties that contain potato genes only. It is envisioned that this CM approach with potato’s own genes will not only prove societally acceptable but may also result in simplifications in the legislation on use of the CM approach. Various parties in the potato research arena intend to cooperate in this novel approach in a number of developing countries where potato substantially contributes to food security. The use of resources such as land, water and energy improves when the effect of late blight is markedly reduced.     

Volatile Compounds of Dry Beans (<Emphasis Type="Italic">Phaseolus vulgaris</Emphasis> L.)

Volatile compounds of uncooked dry bean (Phaseolus vulgaris L.) cultivars representing three market classes (black, dark red kidney and pinto) grown in 2005 were isolated with headspace solid phase microextraction (HS-SPME), and analyzed with gas chromatography mass spectrometry (GC-MS). A total of 62 volatiles consisting of aromatic hydrocarbons, aldehydes, alkanes, alcohols and ketones represented on average 62, 38, 21, 12, and 9 x 10(6) total area counts, respectively. Bean cultivars differed in abundance and profile of volatiles. The combination of 18 compounds comprising a common profile explained 79% of the variance among cultivars based on principal component analysis (PCA). The SPME technique proved to be a rapid and effective method for routine evaluation of dry bean volatile profile.     

Variation in Amylase Activities in Radish (<Emphasis Type="Italic">Raphanus sativus</Emphasis>) Cultivars

The radish (Raphanus sativus) is a root vegetable of the Brassicaceae family which shows amylolytic activity in the taproot. However, there is little information about differences in these amylolytic activities among radish cultivars. We analyzed the amylase activities and starch contents of 7 kinds of radish cultivars. The Koshin cultivar showed the highest amylase activity, with a level approximately 6 times higher than that of the Sobutori cultivar, which had the lowest. Cultivars with higher amylase activities showed higher starch contents. These results suggest that there are intraspecies variations in amylolytic activities in radishes, and positive correlations between amylase activity and starch content.     

Rutin and Total Quercetin Content in Amaranth (<Emphasis Type="Italic">Amaranthus</Emphasis> spp.)

The aim of the study was to confirm the presence of rutin, one of the most common quercetin glycosides, and other quercetin derivatives in plants of genus Amaranthus, to investigate the influence of the species and variety on rutin distribution in the plant and content changes during growing season. The rutin content was determined by micellar electrokinetic capillary chromatography in individual plant parts at the beginning of the growth, at the flowering stage and at the maturity stage of five Amaranthus species. The total quercetin content was determined by micellar electrokinetic capillary chromatography too. The rutin content in amaranth ranged from 0.08 (in seeds) to 24.5 g/kg dry matter (in leaves). Comparison of the determined total quercetin content and the calculated content of quercetin released from rutin did not prove important presence of quercetin or other quercetin derivatives than rutin. Only amaranth leaves sampled at the maturity stage probably contained quercetin or quercetin derivatives. Significant differences in the rutin content were established among species and as well varieties. Amaranthus hybrid and A. cruentus were the best sources of rutin.