A routine test for the relative susceptibility of potato genotypes with resistance to Meloidogyne chitwoodi

Nematology ◽  
2016 ◽  
Vol 18 (9) ◽  
pp. 1079-1094 ◽  
Author(s):  
Misghina G. Teklu ◽  
Corrie H. Schomaker ◽  
Thomas H. Been ◽  
Leendert P.G. Molendijk
Keyword(s):  
Logistic Model ◽  
Multiplication Rate ◽  
Experimental Conditions ◽  
Meloidogyne Chitwoodi ◽  
Second Stage ◽  
Final Population ◽  
Pot Size ◽  
Optimal Protocol ◽  
Dry Soil ◽  
Resistant Genotypes

The population dynamics of Meloidogyne chitwoodi on eight potato genotypes was compared to the susceptible cv. Desiree in four glasshouse experiments. The initial nematode densities consisted of log series 2x, with . Seinhorst’s logistic model was fitted to the final population densities to estimate the parameters maximum multiplication rate (a), maximum population density (M) and the ratios RSa, RSM and . Average RSa and RSM of the seven resistant genotypes were smaller than 0.29%. The ratios on six resistant genotypes and cv. Desiree were the same, 1.3, indicating independence of RS. One genotype stood out with , whereby RSa < RSM. Both RS and were unaffected by pot size or experimental conditions. Screening protocols at second-stage juveniles (g dry soil)−1 in 2 or 3 kg pots were evaluated for distinctiveness between the two genotype groups. Based on the results, an optimal protocol for a routine resistance test is proposed.

Estimation of partial resistance in potato genotypes against Meloidogyne chitwoodi

Nematology ◽  
2011 ◽  
Vol 13 (4) ◽  
pp. 477-489 ◽  
Author(s):  
Thomas Been ◽  
Corrie Schomaker ◽  
Patrick Norshie
Keyword(s):  
Partial Resistance ◽  
Damage Threshold ◽  
Internal Quality ◽  
Yield Reduction ◽  
Initial Population ◽  
Multiplication Rate ◽  
Population Densities ◽  
Meloidogyne Chitwoodi ◽  
Industrial Processing ◽  
Final Population

AbstractThree new potato genotypes, designated AR 04-4107, AR 04-4096 and AR 04-4098, with resistance towards Meloidogyne chitwoodi, and the susceptible cv. Désirée were grown at a range of population densities of M. chitwoodi in a climate-controlled glasshouse in order to establish the presence and degree of partial resistance. Tuber parts of about 12 g were planted at densities (Pi) of 0, 0.5, 1, 2, 4, 8, 16, 32, 64, 128 and 256 second-stage juveniles (J2) (g dry soil)−1. The plants were allowed to grow for a period of 105 days. Tomato cv. Moneymaker was included and inoculated at Pi = 2 J2 (g soil)−1 to verify the quality of the inoculum by measuring the multiplication rate. Plant height was measured weekly over 11 weeks. At harvest, fresh shoot, root and tuber weights, and number of tubers were measured to express yield. Final population densities (Pf) were calculated as the total number of nematodes found in soil and roots. Tubers were scored for visible symptoms and a root-knot index was calculated. The relation between pre-plant population densities (Pi) and nematode densities at harvest (Pf) was fitted using R. The multiplication rate a of M. chitwoodi on AR 04-4107, AR 04-4096, AR 04-4098 and cv. Désirée was 0.55, 0.27, 0.91 and 32, respectively. Partial resistance rsa of AR 04-4107, AR 04-4096 and AR 04-4098 was 1.7%, 0.8% and 2.8%, respectively. Partial resistance expressed as rsM was 0.2%, 0.2% and 0.1%, respectively. It can be concluded that AR 04-4107, AR 04-4096 and AR 04-4098 are strongly partially resistant to M. chitwoodi. Also, the population dynamics curves run almost parallel between both the tested genotypes and the reference cultivar, indicating that a simple and cheap partial resistance test is feasible. When tuber yields were fitted to the Seinhorst model for yield reduction, cv. Désirée showed a minimum yield (m) of 0.86, while all three resistant genotypes suffered no yields losses at all (m = 1), which indicates that the observed resistance was associated with tolerance. As a result of the remarkably high partial resistance, quality damage was low compared with cv. Désirée. The root-knot index, which takes into account internal quality damage of the potato tuber, was below 10 for all genotypes with partial resistance, the lower damage threshold used for industrial processing of consumption potatoes. Visible symptoms on the tuber skin were absent up to densities of 32 J2 (g soil)−1 for genotypes AR 04-4098 and AR 04-4096 and 2 J2 (g soil)−1 for AR 04-4107, and significantly reduced at higher densities when compared with the susceptible cv. Désirée. However, when tuber peels were investigated, egg masses were detected in tubers at almost all initial population densities.

Relative susceptibilities of five fodder radish varieties (Raphanus sativus var. Oleiformis) to Meloidogyne chitwoodi

Nematology ◽  
2014 ◽  
Vol 16 (5) ◽  
pp. 577-590 ◽  
Author(s):  
Misghina G. Teklu ◽  
Corrie H. Schomaker ◽  
Thomas H. Been
Keyword(s):  
Partial Resistance ◽  
Total Yield ◽  
Lower Percentage ◽  
Parameter Estimates ◽  
Screening Methods ◽  
Multiplication Rate ◽  
Meloidogyne Chitwoodi ◽  
Resistant Varieties ◽  
Dry Soil ◽  
Fodder Radish

The fodder radish varieties Anaconda, Contra, Defender, Doublet and Terranova, known to have some partial resistance, were compared to the standard variety, Radical, to estimate their relative susceptibility (RS) for both population dynamic parameters of Meloidogyne chitwoodi and to evaluate dependency. This approach must eventually lead to new screening methods for partial resistance tests. Plants were grown under controlled glasshouse conditions. Twelve densities of nematodes in five replications were used. Five plants per 7 l pot were allowed to grow for a period of 11 weeks until their early flowering stage. Few seedlings of all the varieties at and 64 J2 (g dry soil)−1, and all seedlings exposed to the highest density, J2 (g dry soil)−1, died within a week after germination. Replanted seedlings developed into normal plants. Total yield, expressed as total fresh weight, was not affected by M. chitwoodi. A lower percentage of plants with galls was observed on partially resistant varieties as compared with Radical. For Radical, a maximum multiplication rate (a) of 0.38 and a maximum population density (M) of 6.43 J2 (g dry soil)−1 were estimated. Radical proved to be a bad host for M. chitwoodi with all final populations lower than the . The parameter estimates of (M) for Anaconda, Contra, Defender, Doublet and Terranova were 0.011, 0.006, 0.027, 0.020 and 0.009 J2 (g dry soil)−1, respectively. With Radical taken to be 100% susceptible, this resulted in values of 0.17, 0.10, 0.42, 0.32 and 0.14% of these varieties, respectively, reducing high population levels of M. chitwoodi by more than 98%. There was no correlation between the and the values, indicating that scoring the number of galled plants will not provide a suitable measure for partial resistance.

Damage thresholds and population dynamics of Meloidogyne chitwoodi on carrot (Daucus carota) at different seed densities

Nematology ◽  
2015 ◽  
Vol 17 (5) ◽  
pp. 501-514 ◽  
Author(s):  
William K. Heve ◽  
Thomas H. Been ◽  
Corrie H. Schomaker ◽  
Misghina G. Teklu
Keyword(s):  
Population Dynamics ◽  
Daucus Carota ◽  
Yield Loss ◽  
Dynamic Models ◽  
Quality Data ◽  
Seed Density ◽  
Population Densities ◽  
Meloidogyne Chitwoodi ◽  
Final Population ◽  
Dry Soil

Yield loss of carrot (Daucus carota) cv. Nerac caused by Meloidogyne chitwoodi and population dynamics of this nematode were studied using a range of 13 nematode densities at three seed densities (2, 4, 18 seeds pot−1) in a climate-controlled glasshouse. Yield and quality data were fitted to Seinhorst’s yield models. Final population densities were fitted to the population dynamic models for sedentary and free-living nematodes. The tolerance limits for yield loss were 0.34, 0.62 and 0.50, while that of quality were 0.012, 0.142 and 0.813 second-stage juveniles (J2) (g dry soil)−1 at increasing seed densities, respectively. The minimum yield (m), increased with seed density: 0.25, 0.30 and 0.50; the minimum quality yield was 0.10, 0.08 and 0.15 J2 (g dry soil)−1 at increasing seed densities, respectively. Both maximum multiplication rates and maximum population densities increased with increasing seed density but were generally low. Carrot cv. Nerac can be considered a bad host for M. chitwoodi.

The effect of storage time and temperature on the population dynamics and vitality of Meloidogyne chitwoodi in potato tubers

Nematology ◽  
2018 ◽  
Vol 20 (4) ◽  
pp. 373-385
Author(s):  
Misghina G. Teklu ◽  
Corrie H. Schomaker ◽  
Thomas H. Been
Keyword(s):  
Storage Time ◽  
Storage Temperature ◽  
Hatching Rate ◽  
Multiplication Rate ◽  
Potato Tubers ◽  
Population Densities ◽  
Meloidogyne Chitwoodi ◽  
Second Stage ◽  
Time Required ◽  
Storage Temperatures

Summary The population densities of Meloidogyne chitwoodi in potato tubers stored at 4, 8 and 12°C after 0, 60, 120, 180 and 240 days of storage were assessed. Compared to day 0, storage temperatures of 4 and 8°C reduced population densities to 9 and 35%, respectively, after 240 days of storage, while nematode numbers in tubers stored at 12°C increased 2.5 times. The maximum hatching rate of nematodes from tubers stored at 8 and 12°C increased linearly with storage time. At 4°C it remained constant. The time required for the hatching process to reach the maximum number of second-stage juveniles (J2) decreased with increasing storage temperature. Recovered juveniles of M. chitwoodi from tubers after 180 and 240 days of storage at all three temperatures were still infective and able to multiply on ‘Desiree’ with estimates of the maximum multiplication rate (a) and the maximum population density (M) of 63.6 and 70.8 J2 (g dry soil)−1, respectively.

scholarly journals Seed treatment for management of Meloidogyne javanica in soybean

2017 ◽  
Vol 38 (5) ◽  
pp. 2995 ◽  
Author(s):  
Adriely Alves de Almeida ◽  
Vinicius Hicaro Frederico Abe ◽  
Ricardo Marcelo Gonçalves ◽  
Maria Isabel Balbi-Peña ◽  
Débora Cristina Santiago
Keyword(s):  
Seed Treatment ◽  
Meloidogyne Javanica ◽  
Vitro Assay ◽  
Juvenile Mortality ◽  
Second Stage ◽  
Final Population ◽  
Randomized Design ◽  
Completely Randomized Design ◽  
Soybean Plants

The objective of this study was to evaluate the efficacy of the active ingredient abamectin, either in isolation or in combination with fungicides and insecticides formulated for the industrial seed treatment, on the population of Meloidogyne javanica, tested under greenhouse and in vitro conditions. In both tests, the combination of the following treatments was assessed: abamectin; thiamethoxam; fludioxonil + metalaxyl-M + thiabendazole. Water was used as control for the in vitro assay, whereas under greenhouse conditions, controls were inoculated and not inoculated with M. javanica. The tests were conducted in a completely randomized design with six (in vitro) and ten (greenhouse) replicates. For in vitro studies the effect on hatching, motility, and mortality of juveniles of M. javanica was evaluated. Under greenhouse conditions, the soybean ‘BRS 133’ seeds were treated, and at 15, 30, and 60 days after inoculation (DAI) with M. javanica, plant measurements were recorded. The penetration of second stage juveniles (J2) was also evaluated at 15 DAI. At 30 DAI, galls, egg masses, nematodes/g of root, and final population were evaluated. At 60 DAI, the final population of nematodes in the roots was quantified. The treatments containing abamectin were the most effective in diminishing the hatching of juveniles. All treatments had an effect on nematode motility when compared to the control, and in the treatment containing only abamectin, total juvenile mortality was observed. In greenhouse conditions, at 15 DAI, the treated soybean plants had the highest root mass and shoot length, differing statistically from the inoculated control. All treatments reduced the number of nematodes per gram of root, differing from the control. At 30 DAI, treatment efficiency was observed in reducing the final population of M. javanica, particularly the treatments using abamectin, and abamectin + thiamethoxam + fludioxonil + metalaxyl-M + thiabendazole. However, at 60 DAI, the effect of the treatments on the population of M. javanica did not persist.

Dispersion of TiO2 Nanotubes in a Chitosan Matrix

MRS Advances ◽  
2018 ◽  
Vol 3 (63) ◽  
pp. 3805-3810
Author(s):  
B. Núñez Mendoza ◽  
S.R. Vasquez-García ◽  
N. Flores-Ramírez ◽  
J. L. Rico ◽  
L. Zamora Peredo ◽  
...  
Keyword(s):  
Electrochemical Anodization ◽  
Infrared Spectrometry ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Second Stage ◽  
Chitosan Matrix ◽  
Third Stage ◽  
Membrane Type ◽  
Titanium Foils

ABSTRACTThis work presents the synthesis and characterization of TiO2 nanotubes (NTT) with chitosan (CS). In a first stage, electrochemical anodization of titanium foils was used to generate NTT in a membrane-type arrangement. From these experiments, suitable experimental conditions were selected. In a second stage, the synthesized NTT were detached from the titanium foils by sonication. In the third stage, the detached NTT were dispersed in an acid solution containing CS in various concentrations. Finally, the nanotubes-chitosan (NTT/CS) samples were characterized by Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), and Fourier Transform Infrared Spectrometry (FTIR). Our results showed that the NTT presented very regular tube morphology with -OH and Ti-O- functional groups on the surface. The interaction of NTT and chitosan was enhanced by increasing the time of contact during the synthesis of the titanium composites.

Tuber and root resistance of potato genotypes against Meloidogyne chitwoodi in the presence of Avena strigosa, related to tuber quality

Nematology ◽  
2017 ◽  
Vol 19 (3) ◽  
pp. 281-291 ◽  
Author(s):  
Misghina G. Teklu ◽  
Corrie H. Schomaker ◽  
Thomas H. Been ◽  
Leendert P.G. Molendijk
Keyword(s):  
Tuber Quality ◽  
Initial Population ◽  
Hatching Rate ◽  
Root Weight ◽  
Meloidogyne Chitwoodi ◽  
Tuber Resistance ◽  
Avena Strigosa ◽  
Final Population ◽  
Root Resistance

Relative tuber infestation and quality of two Meloidogyne chitwoodi resistant potato genotypes, AR04-4096 and 2011M1, were compared in glasshouse experiments at initial population density () = 16 second-stage juveniles (g dry soil)−1 in the presence and absence of the bristle oat, Avena strigosa. When A. strigosa was added, ( final population) on both AR04-4096 and 2011M1 increased 130×, increased 1.9 and 3.7×, respectively, while × fresh root weight (FRW)−1 was the same. Nematode hatch from peel of AR04-4096, without A. strigosa, was delayed by 3 weeks but relative hatching rate was increased. Although the RStuber (RS = Relative Susceptibility) of both AR04-4096 and 2011M1 were lower than 1%, in the presence of A. strigosa tuber quality of 2011M1 dropped below the marketable level, while that of AR04-4096 was hardly affected. We conclude that: i) is influenced by root mass; ii) root quality influences nematode hatch; iii) tuber quality is not an estimator for tuber resistance, and the reverse; iv) root resistance is equal to tuber resistance.

scholarly journals Culture medium for mint micropropagation in vitro

2020 ◽  
Author(s):  
N.A. Yegorova ◽  
◽  
M.S. Zagorskaya ◽  
O.V. Yakimova ◽  
◽  
...  
Keyword(s):  
In Vitro Propagation ◽  
Culture Medium ◽  
Medium Composition ◽  
Multiplication Rate ◽  
Ms Medium ◽  
Second Stage ◽  
Clonal Micropropagation ◽  
Propagation Technique

The influence of the culture medium composition on the development of explants at the second stage of clonal micropropagation of mint (Mentha canadensis L. K59(4n)) was studied in order to improve the in vitro propagation technique. It was shown that the maximum multiplication rate (11.5) was provided by MS medium supplemented with BAP (1.0 mg/L), IAA (0.5 mg/L) and 2% sucrose.

scholarly journals Reproduction of Meloidogyne enterolobii in rootstocks and cucumber hybrids

2013 ◽  
Vol 31 (4) ◽  
pp. 618-621 ◽  
Author(s):  
Silvia Renata S Wilcken ◽  
Juliana MO Rosa ◽  
Juliana N Westerich ◽  
Maria José de M Garcia ◽  
Antonio Ismael Inácio Cardoso
Keyword(s):  
Experimental Design ◽  
Initial Population ◽  
Second Stage ◽  
Final Population ◽  
Meloidogyne Enterolobii ◽  
Reproduction Factor

This study aimed to determine the resistance of six rootstocks for cucumber (squash 'Menina Brasileira', pumpkin 'Exposição', 'Shelper', 'Tetsukabuto Takaiama', 'B8-A Tetsukabuto' and 'Excite Ikki') and four Japanese cucumber hybrids ('Yoshinari', 'Kouki', 'Taisho' and 'Tsuyataro') to Meloidogyne enterolobii. The experiment was conducted in greenhouse; each plot consisted of one plant per pot containing 2 liters of autoclaved soil. The experimental design was completely randomized, with five replicates per treatment. Two days after transplanting the seedlings, each plant was inoculated with 5,000 eggs and second-stage juveniles (initial population = Pi) of M. enterolobii. Tomato 'Rutgers' was used as indicative of inoculum viability. Sixty days after inoculated, each plant was evaluated for total number of nematodes in the roots (final population = Pf) and reproduction factor (FR=Pf/Pi). All rootstocks and cucumber hybrids allowed M. enterolobii multiplication, but FR values were lower in 'Shelper', 'Excite Ikki KY' and 'Menina Brasileira' rootstocks. In a second experiment, the low FR in these three rootstocks was confirmed, but with higher values in 'Menina Brasileira'. So, these rootstocks can be recommended to M. enterolobii infested areas, but with low populations, because they don't permit great multiplication of the patogen. It is concluded that 'Shelper' and 'Excite Ikki KY' rootstocks had the lowest FR and can be classified as moderate resistant to this nematode.

Rubberised fabric for fuel soft storage tanks*

2018 ◽  
Vol 45 (7) ◽  
pp. 322-324
Author(s):  
Yu.N. Rybakov ◽  
A.V. Dedov ◽  
D.S. Plokhoi ◽  
D.V. Kolotilin
Keyword(s):  
Diffusion Processes ◽  
Motor Fuel ◽  
Residual Monomer ◽  
Experimental Conditions ◽  
Second Stage ◽  
Before And After ◽  
Nitrile Rubbers ◽  
Two Stages ◽  
Kinetics Of

The kinetics of extraction of dibutyl sebacinate by different grades of motor fuel from rubberised fabric based on a blend of nitrile rubbers SKN-26M and SKN-40M was investigated. The kinetics was determined according to the GOST 9.030-74 standard from the change in weight of the specimen after holding in fuel at 50°C and drying. The change in quality of the fuel after contact with the fabric was recorded from the change in the content of existent gum in fuel according to GOST 1567-97 (ISO 6246-95) and its acidity according to GOST 5985-79 before and after contact with the rubberised fabric. It was shown that the process of extraction proceeds in two stages, the time of the first of which under experimental conditions is not dependent on the type of fuel. The rate of the first stage is much higher than the rate of the second stage. The relation of rates and proportion of extracted fuel at the first and second stages depends on the type of fuel. It can be asserted that the surplus amount of extracted substances is made up of impurities, which include residual monomer or its derivatives and substances used in the synthesis of the rubber. The mechanism of extraction with extractant counterflow into the vulcanisate and its dependence on the grade of petrol is proposed, based on allowance for the diffusion processes in the system.

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