scholarly journals Potencial produtivo de linhagens de amendoim do grupo ereto precoce com e sem controle de doenças foliares

Bragantia ◽  
2001 ◽  
Vol 60 (2) ◽  
pp. 101-110 ◽  
Author(s):  
IGNÁCIO JOSÉ DE GODOY ◽  
SÉRGIO ALMEIDA DE MORAES ◽  
ANDREA ROCHA ALMEIDA DE MORAES ◽  
FRANCISCO SEIITI KASAI ◽  
ANTONIO LÚCIO MELLO MARTINS ◽  
...  
Keyword(s):  
Arachis Hypogaea ◽  
Cercospora Arachidicola ◽  
Cercosporidium Personatum ◽  
Arachis Hypogaea L

Avaliaram-se o potencial produtivo, o rendimento de grãos após descascamento e a massa de grãos de onze linhagens de amendoim (Arachis hypogaea L.) do programa de melhoramento do Instituto Agronômico e da cultivar IAC-Tatu-ST, com e sem controle de doenças foliares. O material genético classifica-se no grupo ereto precoce (A. hypogaea subsp. fastigiata, Waldron). Seis experimentos foram desenvolvidos na época das águas, no Núcleo de Agronomia da Alta Mogiana e na Estação Experimental de Agronomia de Pindorama, em 1994/95, 1995/96 e 1996/97, em esquema com duas parcelas subdivididas, em blocos ao acaso com quatro repetições, em que as parcelas principais consistiram em tratamentos com e sem o controle químico das doenças. As parcelas tratadas foram pulverizadas periodicamente com 3,0 L.ha-1 do fungicida chlorothalonil para controle da mancha-castanha e da mancha-preta (Cercospora arachidicola e Cercosporidium personatum) e da verrugose (Sphaceloma arachidis). A ausência de controle químico resultou em significativas reduções, até de 60%, na produção de todos os genótipos. Com as doenças controladas, as linhagens IAC 5, IAC 21, IAC 22 e IAC 81-12 apresentaram maior potencial produtivo, atingindo 5.000 kg.ha-1 em dois dos experimentos. As linhagens IAC 81-7 e IAC 88-1 apresentaram os melhores desempenhos relativos entre as médias de ambientes com e sem controle químico. As doenças causaram reduções até de 14% no peso médio dos grãos, sobretudo nas linhagens IAC 5, IAC 21 e IAC 22, cujos grãos são de maior tamanho médio. Não foram observadas diferenças significativas em rendimento de grãos entre os tratamentos, na maioria dos ambientes; essa característica mostrou, também, ser pouco influenciada pela presença das doenças.

Control of Early and Late Leafspot on Two Peanut Cultivars1

1983 ◽  
Vol 10 (1) ◽  
pp. 17-21 ◽  
Author(s):  
F. M. Shokes ◽  
D. W. Gorbet ◽  
L. F. Jackson
Keyword(s):  
Disease Control ◽  
Arachis Hypogaea ◽  
Cercospora Arachidicola ◽  
Cercosporidium Personatum ◽  
Pod Yield ◽  
Arachis Hypogaea L ◽  
T1 And T2 ◽  
Disease Pressure

Abstract The effectiveness of four fungicides for control of Cercospora arachidicola Hori (CA) and Cercosporidium personatum (Berk and Curt.) Deighton (CP) on Arachis hypogaea L. ‘Florunner’ and ‘Early Bunch’ was evaluated in 1978 and 1979. Chlorothalonil (3.5 liters/ha) + flowable sulfur on a 10-day schedule (T1) gave the best control of both leafspots. Chlorothalonil alone (2.3 liters/ha) on a 14-day schedule (T2) provided better disease control and higher pod yields than three other fungicide treatments on both cultivars in 1979. With reduced disease pressure in 1980, triphenytin hydroxide + flowable sulfur and mancozeb + flowable sulfur were almost as effective as T1 and T2 in maintaining high pod yield on Florunner. Yields were significantly less both years on Early Bunch for all treatments other than T1 and T2. The incidence of CA leafspot was low both years and CP was the predominant leafspot pathogen. Significantly higher numbers of CP lesions were observed on Early Bunch than on Florunner at 70 and 90 days after planting (DAP) in 1979 and at 110 DAP in 1980. Numbers of CA lesions on the two cultivars were not significantly different. Average pod yields across fungicide treatments of the two cultivars were not significantly different in 1979 or 1980. Differences in disease levels and pod yields were greater among fungicide treatments than between cultivars.

Tank Mix Combinations of Propiconazole and Chlorothalonil for Control of Leaf Spot Diseases of Peanut

1995 ◽  
Vol 22 (2) ◽  
pp. 101-105 ◽  
Author(s):  
A. K. Culbreath ◽  
T. B. Brenneman ◽  
K. L. Reynolds ◽  
J. M. Hammond ◽  
G. B. Padgett
Keyword(s):  
Arachis Hypogaea ◽  
Leaf Spot ◽  
Field Experiments ◽  
Quadratic Functions ◽  
Cercospora Arachidicola ◽  
Spot Intensity ◽  
Linear Quadratic ◽  
Cercosporidium Personatum ◽  
Arachis Hypogaea L ◽  
Non Linear

Abstract Field experiments were conducted in one location in 1993 and two locations in 1994 to determine the effects of propiconazole and chlorothalonil tank mix combinations on severity of early (Cercospora arachidicola) and late (Cercosporidium personatum) leaf spot diseases of peanut (Arachis hypogaea L.). In all tests, 10 treatments consisted of 0 and 63 g a.i./ha of propiconazole and 0, 0.315, 0.63, 0.945, and 1.26 kg a.i./ha of chlorothalonil arranged factorially. In 1993, final leaf spot intensity ratings decreased according to nonlinear quadratic functions of chlorothalonil concentrations applied with and without propiconazole. No improvement in leaf spot control was evident with the addition of more than 0.945 kg a.i./ha of chlorothalonil with 63 g a.i./ha of propiconazole. In 1994, conditions were more conducive for leaf spot development. At the Plains location, final leaf spot intensity ratings decreased according to non-linear quadratic functions of chlorothalonil concentrations alone. Leaf spot intensity ratings decreased linearly with increasing rates of chlorothalonil when applied with 63 g a.i./ha of propiconazole. At Tifton, final leaf spot intensity ratings decreased linearly with increasing rates of chlorothalonil with or without propiconazole. Leaf spot intensity ratings were lower on plants treated with tank mixes of chlorothalonil and propiconazole compared to those treated with chlorothalonil alone. Pod yields increased linearly or according to quadratic functions of rates of chlorothalonil with or without propiconazole in both years and all locations. Across all rates of chlorothalonil, yields were higher from plants treated with propiconazole than those treated with the respective rates of chlorothalonil alone.

Applications of Mixtures of Copper Fungicides and Chlorothalonil for Management of Peanut Leaf Spot Diseases

2001 ◽  
Vol 2 (1) ◽  
pp. 1 ◽  
Author(s):  
A. K. Culbreath ◽  
T. B. Brenneman ◽  
R. C. Kemerait
Keyword(s):  
Arachis Hypogaea ◽  
Leaf Spot ◽  
Field Experiments ◽  
Cercospora Arachidicola ◽  
Copper Oxychloride ◽  
Copper Hydroxide ◽  
Cercosporidium Personatum ◽  
Late Leaf Spot ◽  
Copper Fungicides

Management of early leaf spot (Cercospora arachidicola) and late leaf spot (Cercosporidium personatum) of peanut (Arachis hypogaea) in the southeastern U.S. is dependent upon multiple applications of foliar fungicides. Field experiments were conducted from 1997 to 2000 to compare the efficacy of mixtures of copper hydroxide or copper oxychloride and reduced rates of chlorothalonil with that of full rates of chlorothalonil alone or chlorothalonil + propiconazole. In all tests, rates per ha of 0.70 kg of chlorothalonil + 0.70 kg of copper oxychloride or higher provided leaf spot control that was similar (P > 0.05) to that achieved with standard rates of chlorothalonil (0.84 kg/ha) + propiconazole (0.063 kg/ha). Application of chlorothalonil at 0.56 kg/ha + copper oxychloride at 0.56 kg/ha controlled leaf spot as well as (P > 0.05) chlorothalonil alone at 1.26 kg/ha in five of six tests in which that treatment was evaluated. In three of four tests in 1998 and 1999, application of chlorothalonil at 0.63 kg/ha + copper hydroxide at 0.63 kg/ha controlled leaf spot as well as chlorothalonil alone at 1.26 kg/ha. In both tests in 2000, application of chlorothalonil at 0.84 kg/ha + copper hydroxide at 0.63 kg/ha controlled leaf spot as well as chlorothalonil alone at 1.26 kg/ha. There were no consistent yield differences among the chlorothalonil, chlorothalonil + propiconazole, or chlorothalonil + copper treatments. Accepted for publication 8 November 2001. Published 16 November 2001.

scholarly journals Selection Indices for Simultaneous Selection for Pod Yield and Leafspot Resistance in Peanut (Arachis hypogaea L.)1

1987 ◽  
Vol 14 (1) ◽  
pp. 51-54 ◽  
Author(s):  
R. N. Iroume ◽  
D. A. Knauft
Keyword(s):  
Arachis Hypogaea ◽  
Breeding Value ◽  
Direct Selection ◽  
Index Selection ◽  
Cercospora Arachidicola ◽  
Pod Yield ◽  
Arachis Hypogaea L ◽  
Yield Gain ◽  
Selection For ◽  
Disease Pressure

Abstract The objective of this study was to investigate the possibility of index selection for pod yield and leafspot resistance, causal organisms Cercospora arachidicola Hori and Cercosporidium personatum (Berk. and Curt.) Deighton, in peanut (Arachis hypogaea L.). Eleven crosses were evaluated in the S1 and S2 generations under natural disease pressure for pod yield and disease reaction. Leafspot severity was measured by leaf necrotic area and defoliation. Variances for each trait and covariances between traits were estimated by progeny analysis. Economic weights assigned to the different characters were derived as the ratio of the pod yield for a genotype to the theoretical pod yield gain from leafspot resistance. Indices were constructed and their efficiency both as predictor of the breeding value and relative to individual selection for either trait was evaluated. Index selection for increased pod yield and reduced leafspot susceptibility was between 87% and 100% as efficient as direct selection for either trait. Combining several leafspot severity readings with pod yield did not improve the efficiency of the index. Fourteen to 17% of the breeding value of the population was accounted for by the traits combined in various indices. This indicated that there is potential for improvement of these indices.

scholarly journals Evaluation of Improved Valencia Peanut Varieties for Production in Haiti

2020 ◽  
Vol 47 (1) ◽  
pp. 1-8
Author(s):  
A.M. Fulmer ◽  
T.B. Brenneman ◽  
R.C. Kemerait ◽  
R. Macajoux ◽  
D.A. Carroll ◽  
...  
Keyword(s):  
Arachis Hypogaea ◽  
Leaf Spot ◽  
Yield Potential ◽  
Average Increase ◽  
Cercosporidium Personatum ◽  
Central Plateau ◽  
Late Leaf Spot ◽  
Puccinia Arachidis ◽  
Arachis Hypogaea L ◽  
Plot Design

ABSTRACT Late leaf spot (Cercosporidium personatum) and peanut rust (Puccinia arachidis) are the most important diseases of peanut (Arachis hypogaea L.) in Haiti. Traditional Haitian peanut varieties are not only susceptible to these diseases but are also typically grown without benefit of a fungicide program. Five trials were conducted from 2015 to 2017 to evaluate the performance of six Valencia varieties in Quartier-Morin, Haiti (with an additional trial in 2017 at the Central Plateau) with respect to yield, resistance to rust and leaf spot diseases, and response to a fungicide program. A split-plot design with four or six replications was used in these studies. In each, “variety” was the whole plot and presence or absence of a fungicide program was the subplot. Valencia market types 309 Red, 309 Tan, M2, M3, SGV0801 and a local landrace were compared with and without Muscle ADV (tebuconazole + chlorothalonil, Sipcam) (2.3 L/ha) applied at 45, 60 and 75 days after planting (DAP). Final disease ratings (late leaf spot and peanut rust) were assessed approximately 94 DAP and plots were harvested the day following. In all trials, 309 Tan variety had the least amount of leaf spot and rust, but resulted in the lowest yield in four out of five trials, averaging 1727 kg/ha across fungicide treatments. M3, M2 and 309 Red were generally the numerically highest-yielding varieties, averaging 2906, 2864 and 2541 kg/ha across fungicide treatments, respectively, but were not statistically higher than the local Haitian Valencia, averaging 2374 kg/ha. Three fungicide applications during the season significantly increased yields in most trials for all varieties except 309 Tan. The highest and lowest average increase in yield from fungicide was for 309 Red (1126 kg/ha) and 309 Tan (103 kg/ha), respectively. The results from this study conducted over 2 years and 4 seasons document that while resistance to late leaf spot and rust is available in Valencia varieties, yield potential is not directly associated with that resistance. Also, use of fungicide improves yield potential in more susceptible varieties.

Geographical Distribution of Genetic Diversity in Arachis hypogaea

2001 ◽  
Vol 28 (2) ◽  
pp. 80-84 ◽  
Author(s):  
C. C. Holbrook ◽  
T. G. Isleib
Keyword(s):  
Disease Resistance ◽  
Arachis Hypogaea ◽  
Leaf Spot ◽  
Germplasm Collection ◽  
Cercospora Arachidicola ◽  
Root Knot Nematode ◽  
Sources Of Resistance ◽  
Arachis Hypogaea L ◽  
Race 1 ◽  
The U.S

Abstract The U.S. maintains a large (> 8000 accessions) and genetically diverse collection of peanut (Arachis hypogaea L.) germplasm. It is costly to screen all accessions within this collection for traits that could be useful in cultivar development. The objective of this research was to identify countries of origin that are rich sources of resistance to important peanut diseases. This would allow peanut breeders to focus their efforts on smaller subsets of the germplasm collection. Accessions in the peanut core collection were evaluated for resistance to late (Cercosporidium personatum Berk. & M. A. Curtis) and early (Cercospora arachidicola Hori) leaf spot, tomato spotted wilt Tospovirus (TSWV), the peanut root-knot nematode [Meloidogyne arenaria (Neal) Chitwood race 1], and Cylindrocladium black rot (CBR)[Cylindrocladium crotalarie (Loos) Bell & Sobers]. These data then were examined to determine if genes for resistance clustered geographically. Several geographical areas that appear to be rich sources for disease-resistant genes were identified. China had a relatively large number of accessions with resistance to the peanut root-knot nematode. Peru appeared to be a rich source of material with resistance to CBR. Resistance to late leaf spot was more frequent than expected in accessions from Bolivia and Ecuador. Bolivia was also a valuable source of resistance to early leaf spot. Early leaf spot resistance also was more prevalent than expected in accessions from India, Nigeria, and Sudan. India, Israel, and Sudan were valuable origins for material with resistance to TSWV. Accessions with multiple disease resistance were most common in India, Mozambique, and Senegal. This information should enable plant breeders to utilize more efficiently the genes for disease resistance that are available in the U.S. germplasm collection.

Management of Leaf Spot Diseases of Peanut With Prothioconazole Applied Alone or in Combination With Tebuconazole or Trifloxystrobin

2008 ◽  
Vol 35 (2) ◽  
pp. 149-158 ◽  
Author(s):  
A. K. Culbreath ◽  
R. C. Kemerait ◽  
T. B. Brenneman
Keyword(s):  
Arachis Hypogaea ◽  
Leaf Spot ◽  
Field Experiments ◽  
Yield Response ◽  
Cercospora Arachidicola ◽  
Cercosporidium Personatum ◽  
Late Leaf Spot ◽  
Similar Series

Abstract Field experiments were conducted in Tifton and Plains, GA in 2001–2007 to determine the efficacy of prothioconazole on early leaf spot (Cercospora arachidicola) and late leaf spot (Cercosporidium personatum) of peanut (Arachis hypogaea). In five of six experiments, application of one or both rates (0.18 and 0.20 kg ai/ha) of prothioconazole in sprays 3–6 (chlorothalonil at 1.26 kg ai/ha in sprays 1, 2, and 7) provided leaf spot control superior to tebuconazole (0.23 kg ai/ha) in a similar regime, and superior to chlorothalonil at 1.26 kg ai/ha applied full season (seven times) in four of six experiments. In a similar series of six experiments, application of 0.085 kg ai/ha of prothioconazole + 0.17 kg ai/ha of tebuconazole provided better leaf spot control than tebuconazole (0.23 kg ai/ha) applied in regimes similar to those described above. Leaf spot control with prothioconazole + tebuconazole was similar to chlorothalonil applied at 1.26 kg ai/ha full season in five of eight experiments, but was less effective in the remaining three experiments. Fungicide effects on yield were inconsistent, but in all experiments, yield response with either rate of prothioconazole was similar to or greater than that obtained with 0.23 kg ai/ha tebuconazole on the same schedule. In a third series of four experiments, full-season (seven sprays) application of mixtures of prothioconazole at 0.063 kg ai/ha with trifloxystrobin at 0.063 kg ai/ha gave similar or better leaf spot control than chlorothalonil full season.

Evaluation of Detached Leaf Culture for Screening Peanuts for Leafspot Resistance1

1980 ◽  
Vol 7 (2) ◽  
pp. 98-100 ◽  
Author(s):  
D. J. Foster ◽  
J. C. Wynne ◽  
M. K. Beute
Keyword(s):  
Arachis Hypogaea ◽  
Leaf Spot ◽  
Leaf Age ◽  
Field Tests ◽  
Cercospora Arachidicola ◽  
Simple Method ◽  
Detached Leaf ◽  
Arachis Hypogaea L ◽  
The Relationship ◽  
Resistant Genotypes

Abstract A detached leaf culturing technique has been proposed as a rapid and simple method for screening peanut (Arachis hypogaea L.) genotypes for leafspot resistance. This study was conducted to (a) determine the effect of both leaf age and outdoor plant weathering on infection with Cercospora arachidicola Hori as measured by the detached leaf technique, (b) evaluate the resistance to early leafspot of several peanut genotypes in the field and in the greenhouse using the detached leaf technique, and (c) determine the relationship between leafspot resistance measured in the field and the greenhouse. The age of the leaf had a significant effect on leafspot resistance when evaluated using the detached leaf technique. Younger leaves averaged 11.4 lesions per leaflet compared to 5.6 lesions per leaflet for older leaves. The number of lesions per leaflet was similar for weathered and greenhouse-grown plants. PI 270806, PI 109839, Kanyoma, and PI 259679, four Virginia (ssp. hypogaea var. hypogaea) types, were the most resistant genotypes evaluated in these tests. The number of lesions per leaflet caused by early leaf-spot for the 16 genotypes measured by the detached leaf technique was significantly correlated (r = 0.85) with the same trait measured in the field. PI 109839 had the fewest number of lesions per leaflet in both greenhouse and field tests.

scholarly journals Effects of Postemergence Herbicides on Cercospora arachidicola Hori and Early Leaf Spot of Peanut1

1999 ◽  
Vol 26 (1) ◽  
pp. 4-8 ◽  
Author(s):  
J. A. Baysinger ◽  
H. A. Melouk ◽  
D. S. Murray
Keyword(s):  
Arachis Hypogaea ◽  
Leaf Spot ◽  
Untreated Control ◽  
Conidial Germination ◽  
Leaf Spot Disease ◽  
Common Disease ◽  
Cercospora Arachidicola ◽  
Spot Disease ◽  
Arachis Hypogaea L ◽  
Postemergence Herbicides

Abstract Early leaf spot is a common disease of peanut caused by the fungus Cercospora arachidicola Hori. Experiments were conducted to evaluate the effect of postemergence herbicides on the conidial germination of C. arachidicola and on the incidence of early leaf spot disease in peanut (Arachis hypogaea L.) in a greenhouse. Conidial germination was enhanced (≥ 100%) at concentrations of 1, 100, and 1000 mg/L of 2,4-DB compared with the untreated control. Lactofen reduced conidial germination by 42% compared with the control at concentrations as low as 100 mg/L and completely inhibited germination at concentrations ≥ 5000 mg/L. A concentration of 10,000 mg/L acifluorfen and 2,4-DB completely inhibited conidial germination. Acifluorfen, acifluorfen plus 2,4-DB, and lactofen decreased the sporulation of early leaf spot lesions. Lactofen reduced leaf spot incidence 12% and decreased sporulation of lesions 22% compared with the control. None of the herbicides increased the incidence of early leaf spot on peanut plants or the number of early leaf spot lesions per leaflet when compared with plants that received no herbicide.

Resistance to Late Leafspot Peanut of Progenies Selected for Resistance to Early Leafspot1

1985 ◽  
Vol 12 (1) ◽  
pp. 17-22 ◽  
Author(s):  
Stephen B. Walls ◽  
J. C. Wynne ◽  
M. K. Beute
Keyword(s):  
Latent Period ◽  
Arachis Hypogaea ◽  
Field Data ◽  
Rank Correlation ◽  
Cercospora Arachidicola ◽  
Lesion Area ◽  
Components Of Resistance ◽  
Arachis Hypogaea L ◽  
Susceptible Control ◽  
Field Plots

Abstract Fifty-six F7 peanut (Arachis hypogaea L.) lines previously selected for resistance to early leafspot (Cercospora arachidicola Hori) were evaluated in the field and greenhouse for resistance to late leafspot [Cercosporidium personatum (Berk. & Curt.) Deighton]. After growing in field plots for 12 weeks, differences for numbers of lesions per 15 leaves were found among the lines and between these lines and NC 3033, the susceptible control. Eleven lines with the fewest numbers of lesions and their parents were screened in the greenhouse for components of resistance. These lines had lesions that were significantly smaller, produced lesions with longer latent periods, and produced fewer conidia than NC 3033. Latent periods ranged from 23 to 26 days for the selections compared to 20 days for NC 3033. GP-NC 343 and NC 5 were the most resistant parents with latent periods of 24 days each. A rank correlation of greenhouse and field data revealed that the rank of an entry in the greenhouse for latent period, lesion area and amount of sporulation was correlated with the rank of the entry in the field. Thus, these variables could be used as measurements of resistance to predict the performance of a line in the field for this population. Lines with resistance to late leafspot can be selected from a population of lines with this parentage which have been selected for resistance to early leafspot.

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