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.

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.

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.

The Mesothelial Cells in CAPD Effluent and Their Relation to Peritonitis Incidence

1991 ◽  
Vol 11 (1) ◽  
pp. 22-26 ◽  
Author(s):  
Michiel G.H. Betjes ◽  
Harry J. Bos ◽  
Raymond T. Krediet ◽  
Lambertus Arisz
Keyword(s):  
Dwell Time ◽  
Total Yield ◽  
Mesothelial Cells ◽  
Total Cell ◽  
Lower Percentage ◽  
Total Cell Count ◽  
The Mean ◽  
Turn Over ◽  
Peritoneal Dialysis Effluent

The total cell count and cell differentiation of the overnight peritoneal dialysis effluent (PDE) was analysed in 34 long-term CAPD patients. The mean percentage and yield of mesothelial cells were 3.1% and 0.17 × 106 per PDE. There was a significant lower percentage and yield of mesothelial cells in the PDE of patients with a peritonitis incidence (PI) of more than 2 episodes a year. Independent of dwell time, a positive correlation between the total yield of leucocytes and the yield of mesothelial cells was found. No relation between the amount of phospholipids in the PDE and the yield of mesothelial cells could be shown. Mesothelial cells in the PDE are probably reflecting the turn-over rate of a reactive mesothelium. Whether a low turn-over rate of the mesothelium is causing or is caused by a high PI needs further investigation.

Effect of whole seed tubers, cut seed and within row spacing on potato (cv. Sebago) tuber yield

1990 ◽  
Vol 30 (3) ◽  
pp. 427 ◽  
Author(s):  
PC Strange ◽  
KW Blackmore
Keyword(s):  
Seed Potato ◽  
Tuber Yield ◽  
Total Yield ◽  
Row Spacing ◽  
Multiplication Rate ◽  
Potato Tubers ◽  
The Mean ◽  
Whole Seed ◽  
Cut Seed ◽  
Effect On Yield

Whole seed potato tubers in the size ranges 35-100 g, 101-150 g and 35-150 g were compared with cut seed and a mixed run grade of both whole 35-100 g tubers and cut seed, at within row spacings of 25 and 33.3 cm in rows 81.3 cm wide, at Healesville, Ballarat and Warragul districts in 1986-87 and 1987-88. Whole 35-250 g tubers and 40 cm within row spacing were also included in experiments at Healesville during the 2 seasons. The mean total tuber yield from planting whole 35-150 g tubers (47.9 t/ha) was significantly higher than from planting Run grade seed [44.9 t/ha, 1.s.d. (P=0.05)=2.0]. Yields of 35-100 g and 101-150 g tubers were also significantly higher with plantings of whole seed compared with Cut or Run seed. The mean yield of tubers >250 g was significantly higher from planting Run grade seed (12.0 t/ha) than whole 35-150 g tubers [9.7 t/ha, 1.s.d. (P=0.05)=1.8]. Increasing the within row spacing from 25 to 33.3 or 40 cm significantly increased the yield of tubers >250 g and significantly reduced the yield of 101-150 g tubers. The effect on yield of 35-100 g, 151-250 g tubers and total tuber yield was variable. The mean multiplication rate (total yield/seed planting rate) from plantings of 101-150 g whole seed was significantly lower than from plantings of Cut and Run seed but was increased significantly with plantings of whole 35-100 g seed. Increasing the within row spacing significantly increased the multiplication rate and values from 1 environment were 17.2 at 25 cm, 22.2 at 33.3 cm and 24.6 at 40 cm [l.s.d. (P=0.05)=1.5]. The mean number of tubers per plant was significantly higher from plantings of whole seed (8.0-9.1) than from Cut or Run grade seed [6.8-7.1, 1.s.d. (P=0.05)=0.4] and was increased significantly by increasing the within row spacings from 25 to 33.3 or 40 cm.

scholarly journals Assessment of Greenhouse and Laboratory Screening Methods for Evaluating Potato Foliage for Resistance to Late Blight

Plant Disease ◽  
1997 ◽  
Vol 81 (10) ◽  
pp. 1206-1213 ◽  
Author(s):  
Anne E. Dorrance ◽  
Debra Ann Inglis
Keyword(s):  
Late Blight ◽  
Partial Resistance ◽  
Late Blight Resistance ◽  
Screening Methods ◽  
Stem Cuttings ◽  
Age Classes ◽  
Laboratory Screening ◽  
Potato Foliage ◽  
Lesion Growth ◽  
Leaf Disks

Greenhouse and laboratory screening methods for assessing potato foliage for resistance to late blight were compared using 15 cultivars and advanced breeding selections with known field response to late blight. Screening methods included greenhouse inoculation of plants in several age classes, and laboratory assays of detached leaflets, leaf disks, and stem cuttings. Greenhouse inoculation of plants 7 to 11 weeks after planting, near the time of flowering, corresponded best to results obtained in field evaluations, but there were significant differences in disease severity between separate greenhouse tests. This is consistent with variation in late blight severity on a year-to-year basis when cultivars are compared in the field. The greenhouse inoculation method allowed for testing of several components of partial resistance, such as infection efficiency and lesion growth rate, which may exist for each cultivar. Laboratory assays proved less reliable than greenhouse assays for overall ratings of partial resistance, but could be useful for measuring specific components of resistance. Screening evaluations for late blight resistance should include standard cultivars with known reaction to Phytophthora infestans to reference the disease potential within the screening evaluation.

scholarly journals Breeding for Anthracnose Disease Resistance in Chili: Progress and Prospects

2018 ◽  
Vol 19 (10) ◽  
pp. 3122 ◽  
Author(s):  
Raihana Ridzuan ◽  
Mohd Rafii ◽  
Siti Ismail ◽  
Martini Mohammad Yusoff ◽  
Gous Miah ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Current Knowledge ◽  
Selection Process ◽  
Phenotypic Selection ◽  
Segregation Ratio ◽  
Screening Methods ◽  
Breeding Programs ◽  
Anthracnose Disease ◽  
Yield Production ◽  
Resistant Varieties

Chili anthracnose is one of the most devastating fungal diseases affecting the quality and yield production of chili. The aim of this review is to summarize the current knowledge concerning the chili anthracnose disease, as well as to explore the use of marker-assisted breeding programs aimed at improving anthracnose disease resistance in this species. This disease is caused by the Colletotrichum species complex, and there have been ongoing screening methods of chili pepper genotypes with resistance to anthracnose in the field, as well as in laboratories. Conventional breeding involves phenotypic selection in the field, and it is more time-consuming compared to molecular breeding. The use of marker-assisted selection (MAS) on the basis of inheritance, the segregation ratio of resistance to susceptibility, and the gene-controlling resistance may contribute to the development of an improved chili variety and speed up the selection process, while also reducing genetic drag in the segregating population. More importantly, by using molecular markers, the linkage groups are determined dominantly and co-dominantly, meaning that the implementation of a reliable method to produce resistant varieties is crucial in future breeding programs. This updated information will offer a supportive direction for chili breeders to develop an anthracnose-resistant chili variety.

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.

Cyclic Dominance and Optimal Escapement of Adams River Sockeye Salmon (Oncorhynchus nerka)

1990 ◽  
Vol 47 (4) ◽  
pp. 838-849 ◽  
Author(s):  
D. W. Welch ◽  
D. J. Noakes
Keyword(s):  
Sockeye Salmon ◽  
Net Present Value ◽  
Oncorhynchus Nerka ◽  
Total Yield ◽  
Confidence Regions ◽  
Parameter Estimates ◽  
Magnitude Comparison ◽  
Ricker Model ◽  
Stock Recruitment ◽  
Potential Benefits

We examined escapement policies for a stock-recruitment model with negative between-year interactions. Regardless of the degree of interaction present, the optimal policy is to always equalize escapement. Parameter estimates obtained for the Adams River sockeye salmon (Oncorhynchus nerka) indicate that between-year interactions may occur, but confidence regions include the null hypothesis of no interaction at all (the Ricker model). We conclude that the extreme amplitude of the current recruitment cycle in this stock frustrates statistical identification of interaction. It seems unlikely that between-year interactions will be measurable until the off year runs increase by at least two to three orders of magnitude. Comparison of total yields for the Adams River sockeye shows that an equal escapement policy could increase yields by at least 35% over that obtained by the current cyclic escapement pattern. This is equivalent to obtaining an additional $27 million in total yield per annum from the Adams River stock alone and, assuming a discount rate of 4%, translates into an increase in net present value of $675 million. If between-year interactions do not exist, the potential benefits of moving to an equal escapement policy are even larger, on the order of $3 to $4 billion.

scholarly journals Preferensi Wereng Batang Cokelat terhadap Varietas Padi dan Ketahanan Varietas Padi terhadap Virus Kerdil Hampa

2016 ◽  
Vol 35 (1) ◽  
pp. 1
Author(s):  
Suprihanto Suprihanto ◽  
Susamto Somowiyarjo ◽  
Sedyo Hartono ◽  
Y. Andi Trisyono
Keyword(s):  
Control Method ◽  
Brown Planthopper ◽  
Preference Test ◽  
Susceptible Variety ◽  
Disease Index ◽  
Lower Percentage ◽  
Resistant Varieties ◽  
Check Variety ◽  
Moderately Resistant ◽  
Rice Ragged Stunt Virus

<p>Rice ragged stunt virus (RRSV) is transmitted by brown planthopper in the persistent manner. This disease in recent years has become a serious problem in Indonesia and some other countries, such as China, Vietnam, Philippines, and Thailand. Disease control is usually conducted by the vector control using insecticides, so often causes an environmental pollution. An alternative control method is using the environmentally friendly of resistant varieties. The purpose of this study was to determine the level of preference of brown planthopper (BPH) to some varieties and rice germplasms, the resistance of several varieties against rice ragged stunt virus (RRSV) disease and its effectiveness as an inoculum source of virus (RRSV). A total of 15 varieties of rice were used in preference test of BPH and resistance test to RRSV. The test for resistance varieties to RRSV was conducted by transmission of 2nd instar of BPH for 3 days of acquisition feeding period, 10 days incubation period and 24 hours inoculation period with population density of 3 BPH/plant. Disease index was calculated and used to determine the level of plant resistance. Varieties that showed resistant, moderately resistant and susceptible responses were selected and were used as a source of inoculum to be transmitted on to TN1 variety susceptible check variety to know the effectiveness of varieties as source of virus inoculum. The results showed that of the 15 varieties tested, Situ Bagendit, Utri Merah, Mentik Wangi, Mahsuri, and Inpari 1 each was less favored by BPH to settle and to multiply. Mentik Wangi, Tetep, Utri Merah, and Swarnalata each showed resistant response to RRSV. Transmission test to susceptible variety (TN1) showed that the variety of Situ Bagendit, Inpari 13, Mentik Wangi, and Tetep each has a fairly low effectiveness as a source of inoculum as indicated by the lower percentage of infection and disease index on the transmited test plants.</p>

scholarly journals Bed Mulch Treatment Affects Strawberry Fruit Bronzing and Yield Performance

HortScience ◽  
2005 ◽  
Vol 40 (1) ◽  
pp. 72-75 ◽  
Author(s):  
Kirk D. Larson ◽  
Steven T. Koike ◽  
Frank G. Zalom
Keyword(s):  
Plant Growth ◽  
Vegetative Growth ◽  
Total Yield ◽  
Fruit Size ◽  
Growth Yield ◽  
High Irradiance ◽  
Lower Percentage ◽  
Strawberry Fruit ◽  
Yield Performance ◽  
Ambient Temperatures

Strawberry plants (`Commander') were grown with different polyethylene bed mulches in the 1999-2000 and 2000-2001 production seasons to determine the effect of mulch on plant growth, yield performance and incidence of Type III strawberry fruit bronzing (T3B), a fruit disorder of unknown origin. In 1999-2000, T3B incidence ranged from 1.8% to 3.7% of total yield, and use of clear, full-bed (CFB) mulch resulted in significantly less T3B incidence than either clear center-strip mulch (CS), or yellow-on-black full-bed mulch. Plant canopy vegetative growth and shoot to root dry mass ratios were greatest for CFB compared to other mulch treatments, but there was no effect of mulch treatment on yield or fruit size. Winter temperatures in 2000-2001 were colder than in 1999-2000, with reduced vegetative growth and increased T3B incidence in spring for all mulch treatments. Use of CFB mulch resulted in greater vegetative growth, greater yield, increased fruit size and reduced T3B incidence compared to CS or green full-bed mulch, but there was no difference among mulch treatments for number of T3B fruit per plot for any single fruit harvest interval. In 2000-2001, the onset of severe T3B symptoms on 7 May was preceded by a brief period of ambient temperatures >31 °C. For all treatments, peak T3B incidence occurred from late May to mid-June, a period characterized by high ambient temperatures and high irradiance conditions. Results indicate that temperature and radiation are significant factors in the development of T3B, and that increased plant vegetative growth in winter results in greater yields and a lower percentage of T3B-affected fruit, particularly in years with cold winters. Managing strawberry plantations to optimize plant growth and development in winter appears to be an effective strategy for reducing the severity of this disorder.

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