scholarly journals Effect of rootstock on muskmelon cultivar reaction to vine decline disease and yield under arid conditions

2016 ◽  
Vol 21 ◽  
pp. 47 ◽  
Author(s):  
Q.S. Al Mawaali ◽  
A.M. Al-Sadi ◽  
F.A. Al-Said ◽  
M.L. Deadman
Keyword(s):  
Disease Severity ◽  
Fruit Quality ◽  
Severity Index ◽  
Fruit Shape ◽  
Artificial Inoculation ◽  
Disease Severity Index ◽  
Fruit Number ◽  
Positive Effects ◽  
Decline Disease ◽  
Vine Decline

Monosporascus cannonballus, Rhizoctonia solani and Pythium aphanidermatum are the main causal agents of muskmelon vine decline disease in Oman. This study was conducted to examine the response of six cucurbit rootstocks grafted on four muskmelon scions to the causal agents and fruit quality and quantity. The response of 10 day old Palmira seedlings to artificial inoculation with R. solani pathogen alone revealed more damage to muskmelon seedling whereas P. aphanidermatum and M. cannonballus caused less damage when inoculated singly but more disease severity index when combined with R. solani. Artificial inoculation of different rootstocks produced significantly no damping-off and very low vine decline disease severity index on Mubyeongjangsoo, Titan, Tetsukabuto, Rsscih7458, Ezra and Strong Tosa rootstocks. All rootstocks produced high grafting success and low graft failure with the four selected muskmelon cultivars. Rootstocks enhanced early harvesting of grafted Tamara but had no effect on other scions. Fruit shape was almost not significantly affected by grafting except Samit grafted on Strong Tosa and Caramel grafted on Mubyeongjangsoo produced significantly different fruit shapes compared to ungrafted controls in the spring 2013 trial. Fruits from both grafted Shahd and Tamara showed no significant differences in rind brightness, redness and yellowness from the control. An various effect of rootstock was found on harvesting, fruit number and weight, chlorophyll content, and stem diameter of the scion. Rootstocks enhanced early harvesting and increased fruit number and fruit weight in grafted Tamara scions. There was no significant effect of grafting on fruit TSS. The study shows positive effects of grafting on tolerance to vine decline and on fruit quality and yield. 

scholarly journals Evaluation of the reaction of early maturing maize genotypes to common smut using artificial inoculation

2011 ◽  
pp. 71-77 ◽  
Author(s):  
Majid Zamani ◽  
Vahid Rahjoo ◽  
Maryam Parchamian
Keyword(s):  
Disease Severity ◽  
Severity Index ◽  
Variance Analysis ◽  
Artificial Inoculation ◽  
Disease Severity Index ◽  
Resistant Line ◽  
Maize Genotypes ◽  
Resistant Lines ◽  
Early Maturing ◽  
Tip Injection

In order to study of the resistance of early maize genotypes, 44 lines, and hybrids in 2008 and 30 genotypes in 2009 in RCBD were conducted at Karaj and Esfahan Stations. All of the ears were inoculated by tip injection method at suitable time. Inoculation was carried out with syringe (3ml/each ear) at silking stage. Evaluation was done on ears 3-4 weeks after inoculation. The results of variance analysis and mean comparison showed that there is a different reaction among material to disease. In this study, after harvesting of ears, the resistance of each genotype was determined based on disease severity index (0-7). Among examined lines in 2008, line no. (41) (KE 77004/1-1-1) was specified as susceptible and no. (28 and 42) (KE 77003/1-8-1) and (37A) as resistant lines. Also among hybrids, K SC 400 was identified as resistant hybrid. Also, among lines in 2009, line no. (29) (KE77004/1-1-1) was specified as susceptible and line no. (27) (KE77005/4) as resistant line respectively. Among hybrids, hybrid no. (9) (KE77006/3 ?K1263/1) evaluated as resistant hybrid.

EVALUATION OF NONIONIC SURFACTANTS FOR CONTROL OF CLUBROOT OF CABBAGE USING BAREROOT AND PLUG TRANSPLANTS OF TWO CULTIVARS

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 607b-607
Author(s):  
W. Tietjen ◽  
P.J. Nitzsche ◽  
W.P. Cowgill ◽  
M.H. Maletta ◽  
S.A. Johnston
Keyword(s):  
Brassica Oleracea ◽  
Disease Severity ◽  
Nonionic Surfactants ◽  
Plasmodiophora Brassicae ◽  
Severity Index ◽  
Effective Control ◽  
Disease Severity Index

`Market Prize' and `Bravo' cabbage (Brassica oleracea Var. capitata L.), transplanted as peat plug and bareroot plants into a field naturally infested with Plasmodiophora brassicae, Woronin, were treated immediately after planting with a liquid or a granular surfactant. APSA 80™, applied in transplant water, significantly reduced percent clubbing and disease severity index (DSI) compared to control treatments. Miller Soil Surfactant Granular™ did not significantly reduce percent clubbing or DSI. There was a significant effect of cultivar on percent clubbing and DSI. There was no significant effect of transplant type on percent clubbing or DSI. This year's study culminates five years of investigation of surfactants for clubroot control. Specific surfactants have proven to be an effective control of clubroot in cabbage. Chemical names used: nonylphenoxypolyethoxyethanol (APSA 80™); alpha-alkanoic-hydro omega-hydroxy poly (oxyethylene) (Miller Soil Surfactant Granular™).

scholarly journals Summer Heat and Low Soil Organic Matter Influence Severity of Hazelnut Cytospora Canker

2014 ◽  
Vol 104 (4) ◽  
pp. 387-395 ◽  
Author(s):  
Jay Ram Lamichhane ◽  
Alfredo Fabi ◽  
Leonardo Varvaro
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Disease Severity ◽  
Severity Index ◽  
Stress Factors ◽  
Disease Severity Index ◽  
Positive Correlation ◽  
Summer Heat ◽  
Production Areas ◽  
Cytospora Canker

Cytospora canker, caused by the fungus Cytospora corylicola, is present in hazelnut production areas worldwide. The disease is widespread throughout the main production areas of Italy. The causal agent is considered to be a secondary invader of damaged tissue that attacks mainly stressed plants. However, little is known of disease severity and stress factors that predispose plants to infection. In particular, the role of pedoclimatic factors was investigated. Direct survey indicated that disease severity varied across several study sites. Geostatistics showed a strong positive correlation between disease severity index and summer heat (r = 0.80 and 0.91 for July and August, respectively) and strong negative correlation between disease severity index and soil organic matter (r = –0.78). A moderate positive correlation between disease severity index and magnesium/potassium ratio (r = 0.58) and moderate negative correlations between disease severity index and total soil nitrogen (r = –0.53), thermal shock (r = –0.46), and rainfall (r = –0.53) were determined. No significant correlation between disease severity index and soil aluminum (r = –0.35), soil pH (r = –0.01), and plant age (r = –0.38) was found.

scholarly journals The relationship between SPAD chlorophyll and disease severity index in Ganoderma-infected oil palm seedlings

2019 ◽  
Vol 17 (3) ◽  
pp. 355-358 ◽  
Author(s):  
M.R.M. Rakib ◽  
A.H. Borhan ◽  
A.N. Jawahir
Keyword(s):  
Chlorophyll Content ◽  
Disease Severity ◽  
Oil Palm ◽  
Single Photon ◽  
Linear Trend ◽  
Severity Index ◽  
Quadratic Model ◽  
Wood Block ◽  
Disease Severity Index ◽  
The Relationship

Establishment of disease in oil palm seedlings through artificial inoculation of Ganoderma are widely used for studies of various aspects of plant pathology, including epidemiology, etiology, disease resistance, host-parasite interaction and disease control. The estimation of chlorophyll content in the infected seedlings possibly could provide a good indicator for degree of disease or infection, and changes during pathogenesis. Thus, the objective of this study was to evaluate the relationship between disease severity index (DSI) and chlorophyll content in Ganoderma infected oil palm seedlings. Three-month-old oil palm seedlings were infected with Ganoderma inoculum on rubber wood block (RWB), where 44 isolates of Ganoderma were tested. Disease severity index (DSI) and chlorophyll content using a single-photon avalanche diode (SPAD) meter were recorded at 4 weeks interval for a period of 24 weeks after inoculation (WAI). Pearson's correlation analysis and regression analysis were performed to evaluate the relationship between the variables. It was found that the relationship between DSI and SPAD chlorophyll value was inversely proportional (R = -0.92) in a linear trend (R2 = 0.85). Furthermore, the increasing trend of the DSI across the weeks were fitted in a quadratic model (R2 = 0.99). In contrast, the SPAD chlorophyll value declined in a linear trend (R2 = 0.98). The SPAD chlorophyll value could be considered as a better alternative over the DSI as the SPAD chlorophyll value was strongly related to DSI, as well as able to detect physiological changes in the infected oil palm seedlings at the early stages of pathogenesis. J Bangladesh Agril Univ 17(3): 355–358, 2019

Variation patterns within 153 flax (Linum usitatissimum L.) genebank accessions based on evaluation for resistance to fusarium wilt, anthracnose and pasmo

2008 ◽  
Vol 6 (1) ◽  
pp. 22-32 ◽  
Author(s):  
Axel Diederichsen ◽  
Tatiana A. Rozhmina ◽  
Ljudmilla P. Kudrjavceva
Keyword(s):  
Disease Severity ◽  
Fusarium Wilt ◽  
Linum Usitatissimum ◽  
Indian Subcontinent ◽  
Severity Index ◽  
Disease Severity Index ◽  
Fibre Flax ◽  
Linum Usitatissimum L ◽  
Average Resistance ◽  
Variation Patterns

Germplasm of 153 flax (Linum usitatissimum) accessions from 24 countries held at Plant Gene Resources of Canada (PGRC) was evaluated for resistance to fusarium wilt (Fusarium oxysporum), anthracnose (Colletotrichum lini) and pasmo (Septoria linicola). The screening was conducted at the All-Russian Flax Research Institute (VNIIL) at Torzhok, Russia, over 3 years for fusarium wilt and anthracnose, and over 2 years for pasmo. A disease severity index ranging from 0% (no infection) to 100% (heavy infection) was calculated based on observations after artificial inoculation with the pathogens in the greenhouse (fusarium wilt) or in field nurseries (anthracnose and pasmo). The average disease severity index for fusarium wilt was 56.6 ± 34.4% (range 0–100.0%), for anthracnose 59.8 ± 8.1% (range 43.8–83.9%) and for pasmo 74.2 ± 11.8% (range 27.3–100.0%). The variation of disease severity indices among the years and within each accession was highest for fusarium wilt. Higher than average resistance for all three diseases was found in accessions from East Asia, while germplasm from the Indian subcontinent showed considerably lower than average resistance. Germplasm from North America and South America (mostly linseed) displayed above average resistance to fusarium wilt, while European accessions (mostly fibre flax) showed lower than average resistance to this disease. The different resistance levels reflected the improvements made by plant breeding and differences in the environments under which the germplasm accessions evolved. Accessions with potential use in linseed and fibre flax breeding were identified.

scholarly journals Case Study of an Epidemiological Approach Dissecting Historical Soybean Sclerotinia Stem Rot Observations and Identifying Environmental Predictors of Epidemics and Yield Loss

2018 ◽  
Vol 108 (4) ◽  
pp. 469-478 ◽  
Author(s):  
Mamadou L. Fall ◽  
John F. Boyse ◽  
Dechun Wang ◽  
Jaime F. Willbur ◽  
Damon L. Smith ◽  
...  
Keyword(s):  
Disease Severity ◽  
Yield Loss ◽  
Historical Data ◽  
Severity Index ◽  
Stem Rot ◽  
Total Precipitation ◽  
Disease Severity Index ◽  
Sclerotinia Stem Rot ◽  
Environmental Predictors ◽  
Epidemiological Approach

Sclerotinia sclerotiorum is a significant threat to soybean production worldwide. In this study, an epidemiological approach was used to examine 11 years of historical data from a soybean management performance trial in order to advance our understanding of Sclerotinia stem rot (SSR) development and to identify environmental predictors of SSR epidemics and associated yield losses. Recursive partitioning analysis suggested that average air temperature and total precipitation in July were the most significant variables associated with disease severity. High levels of SSR disease severity index were observed when the average temperature in July was below 19.5°C and total precipitation in July was moderate, between 20 and 108.5 mm. A biphasic sigmoidal curve accurately described the relationship between SSR disease severity index (DSI) and yield, with a DSI threshold of 22, below which minimal yield loss was observed. A 10% increase in the DSI, from 22.0 to 24.2, led to an 11% decrease in yield, from 3,308.14 to 2,951.29 kg/ha. Also, a yield threshold (3,353 kg/ha) that was higher than the annual U.S. average soybean yield (3,039.7 kg/ha) was suggested as an expected yield under low or no SSR pressure in the U.S. Midwest. These thresholds can allow soybean stakeholders to assess the value of disease control and establish an SSR baseline for cost-effective management to protect yields. Because S. sclerotiorum has more than 400 plant host species, and because having quantitative information concerning crop losses is crucial for decision making, this study shows the usefulness of historical data on SSR and, hence, can serve as a model in other SSR pathosystems (canola, dry bean, potato, pea, and so on).

Inheritance of resistance to Mal de Río Cuarto (MRC) disease in Zea mays (L.)

2002 ◽  
Vol 139 (1) ◽  
pp. 47-53 ◽  
Author(s):  
M. A. DI RENZO ◽  
N. C. BONAMICO ◽  
D. D. DÍAZ ◽  
J. C. SALERNO ◽  
M. M. IBAÑEZ ◽  
...  
Keyword(s):  
Zea Mays ◽  
Plant Height ◽  
Disease Severity ◽  
Agronomic Traits ◽  
Severity Index ◽  
Point Estimate ◽  
Environment Interaction ◽  
Disease Severity Index ◽  
Evaluation Activity ◽  
Genotype Environment Interaction

No genetic estimates for resistance to Mal de Río Cuarto (MRC) disease in Zea mays (L.) are currently available in the literature. Therefore, the objectives of this investigation were (i) to estimate the variance and heritability of partial resistance to MRC disease and of other agronomic traits from maize families and (ii) to examine associations among MRC disease severity values across different environments and between MRC and other agronomic traits. These estimations, obtained in an endemic area, could contribute to the design of efficient enhancement programmes and evaluation activity for the improvement of MRC resistance. The research was conducted by testing 227 F3 derived-lines from a cross between a susceptible dent line, Mo17, and a partially resistant flint line, BLS14, for MRC disease at two Río Cuarto locations in each of 2 years. The resistance of the lines, measured with a disease severity index (DSI), was normally distributed across environments. Genotypic variances were highly significant on all scoring environments. Estimates of genotype–environment interaction were also significant, suggesting that certain genotypes have little stability over different environments. For disease severity index all estimates demonstrated moderate heritabilities ranging from 0.44 to 0.56 and were similar when based on individual environments or across environment. Confidence interval widths ranged from 34.88 to 50.30% as large as the heritability point estimate. The correlations between environments were small enough to indicate that families did not rank similarly in individual environments for MRC resistance. Disease severity index correlated significantly (P<0.01) with plant height, leaf surface, leaf border, leaf length and tassel type. Heritability estimates for plant height and tassel type were 0.48 and 0.38 respectively and for the various leaf traits heritability values were very low. On the basis of the substantial genotype–environment interaction and the little association between DSI values in the different environments, selection for an increased resistance to MRC disease would require evaluation of germplasm across multiple years and locations. Tassel type would be a useful predictor of DSI and can be used effectively to improve screening procedures.

Resistance of standing milkvetch (Astragalus adsurgens) varieties to Embellisia astragali

2012 ◽  
Vol 63 (4) ◽  
pp. 351 ◽  
Author(s):  
B. H. Yu ◽  
Z. B. Nan ◽  
Y. Z. Li ◽  
H. L. Lin
Keyword(s):  
Disease Severity ◽  
Field Experiments ◽  
Agronomic Traits ◽  
Disease Incidence ◽  
Dry Weight ◽  
Severity Index ◽  
Field Conditions ◽  
Disease Severity Index ◽  
Greenhouse Experiments ◽  
Astragalus Adsurgens

Yellow stunt and root rot caused by Embellisia astragali are major factors contributing to declining yields of standing milkvetch (Astragalus adsurgens). The resistance of ten varieties of standing milkvetch to E. astragali was evaluated under laboratory, greenhouse, and field conditions. Seed germination/emergence, shoot and root length, plant dry weight, disease incidence, mortality, and disease severity index were monitored. The results show that Shanxi and Zhongsha No. 1 varieties had the best agronomic traits and lowest levels of disease in all experiments, while the varieties Neimeng and Ningxia had the highest susceptibility to disease. Germination/emergence differed significantly (P < 0.05) between varieties after inoculation, and compared with the control, germination/emergence of inoculated treatments of nine varieties decreased on average by 1.5% in laboratory experiments and by 4.1% in greenhouse experiments at 15 days after inoculation. Inoculation reduced shoot length by an average of 24.4% and 41.5% (P < 0.05) in laboratory and greenhouse experiments, respectively, in six of ten varieties. All varieties showed significantly (P < 0.05) lower plant dry weight following inoculation, with reductions ranging from 0.3 to 0.6 mg in the laboratory and from 82.6 to 149.4 mg in the greenhouse. Resistance to the pathogen was evaluated on the basis of disease incidence, a disease severity index (DSI), and mortality; varieties showing different resistance were grouped using cluster analysis. There were significant correlations between the results of laboratory and greenhouse experiments (r = 0.79; P < 0.01) and between greenhouse and field experiments (r = 0.83; P < 0.01) across all varieties. Multiple regression analysis between laboratory/greenhouse and field experiments on DSI suggested that screening in the laboratory/greenhouse could be an alternative method of rapidly estimating DSI under field conditions.

scholarly journals Effect of grafting on resistance to vine decline disease, yield and fruit quality in muskmelon cv. Sawadi

2019 ◽  
Vol 23 (1) ◽  
pp. 2
Author(s):  
Qais Al-Mawaali ◽  
Abdullah M Al-Sadi ◽  
Fahad A Al-Said ◽  
Mohammed Shafiur Rahman ◽  
Intisar Al-Zakwani ◽  
...  
Keyword(s):  
Field Experiments ◽  
Consumer Preference ◽  
Fruit Shape ◽  
Consumer Acceptance ◽  
High Yield ◽  
Farming Community ◽  
Yield Production ◽  
Decline Disease ◽  
Vine Decline ◽  
Graft Success

A study was conducted to evaluate graft success, resistance to vine decline disease and effect of grafting on quality and yield of muskmelon. Two field experiments, conducted in Oman, showed that muskmelon cv. Sawadi grafted on six cucurbit rootstocks gave high grafting success: 97.6-99.1% (avg. 98.6%) and 92.4-96.9% (avg. 95.3%) under field conditions in fall 2012 and spring 2013 respectively. No significant differences were observed between seasons among the six treatments and a non-grafted control in consumer preference for odor and firmness, fruit shape, flesh vitamin C, micronutrient content  and TSS (sucrose %) or pH in spring 2013 (P > 0.05). The concentration of phosphorus and sodium significantly decreased in both seasons in all treatments in comparison to the control (P > 0.05). In both seasons potassium content significantly increased when Rsscih7458 and Mubyeongjangsoo rootstocks were used (P < 0.05). Strong Tosa rootstocks showed zero graft failure, high resistance to vine decline disease, high yield production and higher TSS (sucrose %) as compared to other rootstocks. Strong Tosa and Tetsukabuto rootstocks showed significantly higher consumer acceptance for rind color, flesh color and overall consumer acceptance in spring 2013 and was also less affected by seasonal changes. Results suggested that by grafting muskmelon cv. Sawadi some quality attributes may be improved in addition to the increased level of resistance to disease. However, additional trials are required to make final recommendations for the farming community.

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