scholarly journals IDENTIFICATION OF STABLE RESISTANCE TO PHYTOPHTHORA INFESTANS IN POTATO GENOTYPES EVALUATED IN FIELD EXPERIMENTS IN PERU

2007 ◽  
Vol 43 (3) ◽  
pp. 353-363 ◽  
Author(s):  
E. G. WULFF ◽  
W. PÉREZ ◽  
R. J. NELSON ◽  
M. BONIERBALE ◽  
J. A. LANDEO ◽  
...  
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Principal Components ◽  
Field Experiments ◽  
Quantitative Resistance ◽  
Year Effect ◽  
Progress Curve ◽  
Ammi Analysis ◽  
Stability Of Resistance ◽  
Moderately Resistant

In this study, genotype by environment (G × E) interactions and phenotypic stability of resistance to Phytophthora infestans, the cause of late blight, were analysed in Peru for 13 potato genotypes, using additive main effects and multiplicative interaction (AMMI) analysis and Huehn's non-parametric test. The potato genotypes were tested in seven experiments over two years in the vicinity of Comas, Peru, an area used by the International Potato Center to screen for resistance to late blight. Results of the two analyses generally correlated and indicated that quantitative resistance to P. infestans was stable under field conditions for all the genotypes tested. The first two principal components (PCA1 and PCA2) of the AMMI analysis explained 54% of the G × E interaction sum of squares. A biplot of the two principal components demonstrated a strong year effect in the G × E interaction. By plotting yearly means of the relative area under the disease progress curve (rAUDPC), genotypes could be assigned to one of three resistance categories, resistant, moderately resistant or susceptible, but the need for a more readily applicable and truly quantitative scale for resistance was noted. Based on these studies, standards can be selected for use in screening in the area where they were tested. After further testing in other locations, a standard set drawn from these genotypes could be identified and a quantitative scale developed for evaluation of resistance under short day conditions.

scholarly journals Evaluation of potato (Solanum tuberosum L.) genotypes for resistance to late blight at Sinana Southeastern Ethiopia

2016 ◽  
Vol 6 (1) ◽  
pp. 21-25 ◽  
Author(s):  
Getachew Asefa ◽  
Wassu Mohammed ◽  
Tesfaye Abebe
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Agricultural Research ◽  
Solanum Tuberosum L ◽  
Block Design ◽  
Severity Index ◽  
High Yield ◽  
Mean Values ◽  
Progress Curve ◽  
Moderately Resistant

Late blight caused by Phytophthora infestans (Mont.) de Bary, is one of the most significant constraints to potato production in Bale high lands and other regions of Ethiopia. Hence, this requires to develop high yielding and late blight resistant varieties. Therefore, this study was conducted to determine host resistance of potato against Phytophthora infestans in order to develop late blight resistant/tolerant genotypes. The experiment was laid out in randomized complete block design with three replications at Sinana Agricultural Research Center during 2014 main cropping season. The genotypes showed highly significant (P<0.01) differences for all the characters studied. Genotypes exhibited wide ranges of mean values for all characters. The highest total tuber yield (46.1 t ha-1) was obtained from the advanced clone, CIP-392640.524 followed by Belete (41 t ha-1). Late blight appeared early on farmer's cultivar Kellacho (48 days after planting) and late on advanced clones CIP- 399062.102(74 days after planting). Percent severity index (PSI) and area under disease progress curve (AUDPC) ranged from 33.91 to 91.67% and 105 to 2370, respectively. Eleven newly introduced clones and the released variety "Belete" recorded PSI 33 to 39.7% and AUDPC 105 to 264.1. Hence, these genotypes can be categorized as moderately resistant. The study revealed the presence of considerable variability in tested genotypes for economically important traits and the higher chance of selecting genotypes with high yield and moderately resistant to late blight. However, it appears that further evaluation of genotypes across seasons and locations to identify genotypes that could be released as varieties seem to be quite pertinent.Int. J. Agril. Res. Innov. & Tech. 6 (1): 21-25, June, 2016

scholarly journals Potential use of fresh mulch to curb potato late blight epidemics in Brazil

2020 ◽  
Vol 46 (3) ◽  
pp. 191-197
Author(s):  
Nilceu Ricetti Xavier de Nazareno ◽  
Maria Renate Finckh ◽  
Lutécia Beatriz dos Santos Canalli ◽  
Inês Fumiko Ubukata Yada ◽  
Jackson Kawakami
Keyword(s):  
Late Blight ◽  
Field Experiments ◽  
Integrated Management ◽  
Thick Layer ◽  
Elephant Grass ◽  
Plant Type ◽  
Progress Curve ◽  
Promising Practice ◽  
Fall Experiment ◽  
Potential Use

ABSTRACT Field experiments were conducted during spring 2014 and fall and spring 2015 to determine the effect of fresh mulch on the development of Phytophthora infestans epidemics, in Lapa Municipality, Parana State, southern Brazil. The used cultivars were ‘Agata’, susceptible, and ‘BRS Ana’, moderately susceptible. The main treatment consisted in manually applying a 10cm-thick layer of fresh mulch when potato sprouts were emerging. Fresh mulch was prepared with plants available at that time of the year. For the spring experiments, fresh mulch was a mixture of oats, rye grass and wild radish (60 t/ha) and for the fall experiment, semi-ripe elephant grass (90 t/ha). Plots consisted of six 10m-long rows, spaced at 0.8m, containing 28 plants per row. Experimental design was in completely randomized blocks with four replicates. Natural inoculum was adopted. Percentage of leaf area was weekly estimated until the end of the plant cycle and the area under the disease progress curve (AUDPC) was calculated. Application of fresh mulch significantly reduced AUDPC by 32.1%, 12.4% and 23.1%, compared to control in all seasons, for ‘BRS Ana’ and by 26.1%, 2.8% and 12.0% for ‘Agata’. Application of fresh mulch showed to be a promising practice for the integrated management of late blight and for the protection of yields, especially in periods more favorable to the development of the disease. More detailed studies should be conducted on the plant type and amount of fresh mulch to be used, as well as on the possibility of reducing concentrations or increasing intervals between fungicide sprays.

scholarly journals Classifying the Relative Host Reaction in Potato Cultivars and Breeding Lines to the US-8 Strain of Phytophthora infestans in Minnesota

Plant Disease ◽  
2003 ◽  
Vol 87 (8) ◽  
pp. 983-990 ◽  
Author(s):  
J. C. Jenkins ◽  
R. K. Jones
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Rank Correlation ◽  
The United States ◽  
Spearman Rank Correlation ◽  
Breeding Lines ◽  
Spearman Rank ◽  
Progress Curve ◽  
Tuber Blight ◽  
The Us

A total of 32 commercial cultivars grown in the United States and 15 potato breeding lines and non-U.S. cultivars were evaluated at Rosemount, MN for their reaction to the US-8 strain of Phytophthora infestans. Commercial red-, russet-, and white-skinned cultivars tested in the commercial cultivar trial (COMC) in 1996 and 1997 were susceptible (S) to moderately susceptible (MS) to this organism, except for Elba, which ranked as moderately resistant (MR). Yellow-fleshed cvs. Hertha, Santé, and Agria were screened in the late blight nursery (LB1) in 1997 and 1998 and classified as S to MS while Island Sunshine, Brador, and Aziza were classified as MR. The Scottish breeding line G6582-3 and U.S. breeding lines A90586-11, AWN86514-2, AWN85624-5, B0692-4, B0718-3, and B0767-2 were classified as resistant (R). Comparison among entries was based on the area under the disease progress curve (AUDPC). Spearman rank correlation for AUDPC in the 1996 and 1997 COMC trials at 14 to 18 days after inoculation (r = 0.65, P < 0.01) was greater than any other interval tested. The Spearman rank correlation for AUDPC in the 1997 and 1998 LB1 trials at 14 to 18 days after inoculation was r = 0.87, P < 0.01 and increased only slightly in successive assessment dates, suggesting that, in Minnesota, effective evaluation of the foliar infection of late blight can occur at 18 days after inoculation or later. The average tuber blight incidence for the COMC trials at harvest was 10.0% in 1996 and 9.7% in 1997. The average tuber blight incidence for the LB1 trials at harvest was 4.3% in 1997 and 14.6% in 1998. Pearson correlations between tuber blight incidence and foliar disease for the COMC trials was very low; however, for the LBl trials, it was significant in both 1997 (r = 0.53, P < 0.01) and 1998 (r = 0.53, P < 0.01). Asymptomatic tubers harvested from the COMC trials developed additional tuber blight when stored 28 days at ambient temperatures and still more when stored for another 5 months at 5°C. Surviving tubers of nine entries were planted in field trials during 1997 and 1998 to determine if plants that develop from tubers exposed to P. infestans could manifest late blight in the subsequent season. Late blight failed to develop throughout the trials in either year.

scholarly journals Sprinkling Irrigation Enhances Production of Oospores of Phytophthora Infestans in Field-Grown Crops of Potato

2000 ◽  
Vol 90 (10) ◽  
pp. 1105-1111 ◽  
Author(s):  
Yigal Cohen ◽  
Sonja Farkash ◽  
Alexander Baider ◽  
David S. Shaw
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Mating Type ◽  
Field Experiments ◽  
Soil Surface ◽  
Field Trials ◽  
Detached Leaves ◽  
Oospore Formation ◽  
Potato Crops ◽  
Host Tissues

Two field experiments were conducted to study the effect of overhead sprinkling irrigation on oospore formation by the late blight fungus Phytophthora infestans in potato. Total rain (natural + sprinkling) accumulated in treatments of experiment 1 (winter 1997 to 1998) were 765, 287, and 219 mm and treatments of experiment 2 (winter 1999 to 2000) were 641, 193, and 129 mm. Sporangia from 11 isolates of P. infestans were combined in eight pairs, seven of A1 and A2 and one of A2 and A2 mating type, and were sprayed on field-grown potato crops (42 plants per plot at 7 m2 each) and examined for their ability to form oospores in the host tissues. In experiment 1, oospores were recorded in a total of 132 of 1,680 leaflets (7.9%), 24 of 105 stems, and 2 of 90 tubers. In experiment 2, oospores were recorded in 40 of 519 leaflets (7.7%), but not in any of the 90 stems or the 45 tubers examined. Both the proportion of leaflets containing oospores and the number of oospores per leaflet increased with time after inoculation and were dependent on the rain regime, the position of leaves on the plant, and the isolate pair combination. In both field trials, increasing the rainfall significantly enhanced oospore production in leaves. Leaf samples collected from the soil surface had significantly more oospores than those collected from the midcanopy. Two pairs in experiment 1 were more fertile than the others, whereas the pair used in experiment 2 was the least fertile. The total number of oospores per leaflet usually ranged from 10 to 100 in experiment 1, but only from 2 to 10 in experiment 2. Maximal oospore counts in the field were 200 and 50 in experiments 1 and 2, respectively, but ranged from ≈2,000 to 12,000 oospores per leaflet in detached leaves in the laboratory. We concluded that P. infestans can produce oospores in the foliage of field-grown potato crops, especially when kept wet by regular overhead sprinkling irrigation, but production was far below that in the laboratory.

scholarly journals Protection of Susceptible Potato Cultivars Against Late Blight in Mixtures Increases with Decreasing Disease Pressure

2006 ◽  
Vol 96 (7) ◽  
pp. 777-783 ◽  
Author(s):  
F. Pilet ◽  
G. Chacón ◽  
G. A. Forbes ◽  
D. Andrivon
Keyword(s):  
Late Blight ◽  
Potato Cultivar ◽  
Progress Curve ◽  
Late Blight Disease ◽  
Natural Pressure ◽  
Blight Disease ◽  
Disease Pressure ◽  
Moderately Resistant ◽  
The Impact ◽  
Cultivar Mixtures

Cultivar mixtures can reduce potato late blight severity on susceptible cultivars. While alternating rows of susceptible and resistant cultivars would be more acceptable than random mixtures for commercial use, they increase the genotype unit area, which is an unfavorable factor for mixture efficiency, and have been minimally efficient when disease pressure is high. The effects of disease pressure on the performance of alternating rows of cultivars possessing various types and levels of resistance were investigated in 2000 and 2001 near Quito, Ecuador, where natural pressure of late blight is high. The experiments included the highly susceptible cvs. Cecilia in 2000 and LBr37 in 2001, as well as C114 (moderately resistant) and PAN (highly resistant), planted as pure stands and as the three possible two-way combinations. Different disease pressures were obtained with three spraying schedules of a contact fungicide: nontreated, one spray every second week, and one spray weekly. The area under the disease progress curve (AUDPC) on the susceptible cultivar was 0 to 20% less in mixed than in pure plots when no fungicide was applied, 13 to 26% less with a biweekly application of fungicide, and 32 to 53% less with a weekly application. These values are comparable to those obtained in previous experiments in smaller plots with designs maximizing the distance between susceptible plants. No significant differences in mixture performance were observed according to the resistant cultivar included. Effects on yield were minimal, because of the impact of factors other than late blight. Disease pressure therefore appears as a major factor conditioning the efficiency of potato cultivar mixtures against late blight.

scholarly journals Efficacy of fungicide mixtures for the management of Phytophthora infestans (US-1) on potato

2010 ◽  
Vol 90 (1) ◽  
pp. 19-29 ◽  
Author(s):  
F.N. Muchiri ◽  
R.D. Narla ◽  
O.M. Olanya ◽  
R.O. Nyankanga ◽  
E.S. Ariga
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Tuber Yield ◽  
Severe Disease ◽  
Resistance Management ◽  
Foliar Blight ◽  
Progress Curve ◽  
Fungicide Mixtures ◽  
Spray Regimes ◽  
Disease Pressure

Fungicide application strategies (timing, frequency, rates and mixtures) are important for the control and resistance management of potato late blight caused by Phytophthora infestans. The efficacy of fungicide mixtures consisting of fenamidone + mancozeb and propamocarb HCL + mancozeb at various rates and in spray regimes containing metalaxyl and mancozeb was evaluated for late blight control (US-1) at four locations in Kenya. Propamocarb HCL + mancozeb significantly (P < 0.05) reduced foliar blight compared with mancozeb and the untreated control under moderate to severe disease pressure. Disease severity was significantly lower following application of propamocarb HCL + mancozeb at a rate of 4L ha-1 than at rates of 2L and 3L ha-1 in 1999 and 2000, but it was not significantly lower following applications at a rate of 3L ha-1 in 2000 and 2001. There were no significant differences in mean final late blight score among the three rates of 0.9, 1.0 and 1.1 kg ha-1 of fenamidone + mancozeb. All fungicide mixtures and application sequences significantly reduced the area under the disease progress curve and final late blight scores as compared with the unprotected control. Total and marketable tuber yield significantly (P < 0.05) increased in all fungicide-treated plots.

scholarly journals Identification of Interspecific Potato Hybrids with Combined Resistance to Late Blight (Phytophthora Infestans) and Nematode (Globodera Rostochiensis)

2020 ◽  
Vol 74 (3) ◽  
pp. 188-195
Author(s):  
Nadezhda Zoteyeva ◽  
Guna Sprūde ◽  
Natalia Klimenko ◽  
Ieva Mežaka
Keyword(s):  
Molecular Markers ◽  
Late Blight ◽  
Phytophthora Infestans ◽  
Late Blight Resistance ◽  
Globodera Rostochiensis ◽  
Cyst Nematode ◽  
Potato Yields ◽  
Highly Correlated ◽  
Interspecific Potato Hybrids ◽  
Moderately Resistant

AbstractLate blight (agent Phytophthora infestans) and potato cyst nematode (PCN) caused by Globodera rostochiensis are economically important pathogens, which may significantly reduce potato yields. In this study interspecific potato hybrids were used as a source of resistance for combined resistance to economically important potato pathogens: late blight and cyst nematode. The aim of our study was to identify hybrid progenies with combined resistance to both pathogens and to verify the applicability of several molecular markers associated with resistance to G. rostochiensis pathotype Ro1 to identify resistant plants. Ninety-two clones of eleven original interspecific potato hybrids obtained in crosses with the cultivated S. tuberosum group tuberosum, S. tuberosum group Andigena, S. tuberosum group Phureja and wild S. guerreroense, S. microdontum, S. kurtzianum, S. neoantipoviczii and S. tarijense potato species were screened in bioassays and by molecular markers. PCN resistant or moderately resistant clones were found among the progenies of nine hybrids. Results were highly correlated with resistance status detected by molecular markers linked to the H1 (marker 57R) and Gro1-4 (marker Gro1) genes. Marker CP113 (linked to the H1 gene) was not polymorphic and failed to detect resistance status. Combination of foliar late blight resistance and resistance to PCN was identified in hybrids obtained in crosses with plants of species S. microdontum, S. tarijense and S. phureja and in the hybrid between S. guerreroense and Black’s P. infestans race differential carrying gene R-5.

scholarly journals CANOPY REFLECTANCE MEASUREMENTS USED TO ESTIMATE LATE BLIGHT (PHYTOPHTHORA INFESTANS) INFLUENCE ON POTATO YIELD CANOPY REFLECTANCE MEASUREMENTS USED TO ESTIMATE LATE BLIGHT (PHYTOPHTHORA INFESTANS) INFLUENCE ON POTATO YIELD

2020 ◽  
Vol 13 ◽  
pp. 21-27
Author(s):  
Manuela Hermeziu
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Field Experiments ◽  
Block Design ◽  
Potato Yield ◽  
Planting Density ◽  
Canopy Reflectance ◽  
Reflectance Measurements

"The present study was conducted to investigate potato late blight (Phytophtora infestans) influence on leaf chlorophyll level using datasets extracted from multispectral data captured at the canopy level. Field experiments were carried out to the National Institute of Research and Development for Potato and Sugar Beet Brasov, Romania in 2014-2016 period. It was used a complete randomized block design with four replicates, two planting distances between plants on row (25 and 30cm) and different fungicides, control technologies. Normalized Difference Vegetation Index (NDVI) was introduced to achieve a spectral vegetation index that can separate the vegetation from the uncovered ground. It is defined as the ratio between the infrared bands-red differences and sum them. Due to the different growth conditions, the effects of resulting variants from combinations of factors -varieties-planting density-late blight control technology-on the tubers yield have manifested with different intensity. In two of three years, the average NDVI value of plants grown at a density of 53.3 thousands hill/ha was significantly lower than the values determined at a density of 44.4 thousands hill/ha (NDVI 0.817 compared to 0.859 in 2014 and 0.905 compared to 0.895 in 2015). The correlation between the average values of NDVI yields and tubers were positive."

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