Incidência de fungos e quantificação de danos em sementes de genótipos de arroz

Malavolta, Vanda Maria Angeli; Soligo, Elaine de Arruda; Dias, Débora Daiana; Azzini, Luiz Ernesto; Bastos, Cândido Ricardo

doi:10.1590/s0100-54052007000300012

Cited by 15 publications

(23 citation statements)

References 1 publication

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“…A infecção de panículas das cultivares IAC 101 e IAC 103 com B. oryzae em condições de campo, no Estado de São Paulo, causou a diminuição em peso e número de grãos, emergência de plântulas e o peso de 100 panículas (10,11).…”

Section: Introductionunclassified

Influência da adubação nitrogenada, época de plantio e aerosporos sobre a severidade da mancha de grãos em arroz de terras altas

et al. 2011

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A mancha de grãos (MG) ocupa o segundo lugar em importância econômica entre as doença s do a rroz. Foi estuda da a influ ência de níveis de adubação nitrogenada, época de plantio e concentração de esporos no ar sobre a severidade da doença no campo. A severidade de MG, na cultivar BRS Bonança, foi avaliada em duas épocas de plantio (30 /11/2006 e 2 1/12 /200 6) e cinco doses de a duba ção nitrogenada (0 , 3 0 , 6 0 , 1 2 0 e 2 4 0 k g de N.ha -1 ) u tiliza ndo o delinea mento experimental de blocos ao acaso em esquema de parcelas subdivididas com três repetições. O efeito de dose de N sobre a severidade de MG nã o foi significa tivo. A correla çã o entre a severida de de MG e espiguetas vazias foi positiva e significativa. A população de fungos no ar (aerosporos) foi quantificada utilizando armadilhas volumétricas, Silva-Lobo, V.L.; Lacerda, M.G.; Filippi, M.C.; Silva, G.B; Prabhu, A.S. Influência da adubação nitrogenada, época de plantio e aerosporos sobre a severidade da mancha de grãos em arroz de terras altas.Summa Phytopathologica, v.37, n.3, p.110-115, 2011. Palavras-chave adicionais:Oryza sativa, armadilha volumétrica, doenças de final de ciclo, epidemiologia.Rotorod Sampler, desde a emissão até o amadurecimento das panículas. A mancha de grãos aumentou linearmente com tempo (r = 0,98; P < 0 ,0 1 ), o mesmo nã o ocorreu com o a u mento tota l de fu ngos qu e variou de 0,23 a 2,97 esporos/litro de ar/minuto. Os fungos presentes no ar em ordem decrescente de concentração foram Nigrospora sp., Pyricularia oryzae, Pithomyces sp., Alternaria sp., Cercospora sp., Fusarium sp., Curvularia sp. e Bipolaris sp. Estes fungos e Phoma sp. entre outros ta mbém fora m detectados no teste de sa nida de de sementes. A correlação entre a quantidade de esporos de P. oryzae e outros fungos foi linear e positiva (r = 0,80, P < 0,01). O número de esporos au mentou com o a umento da u mida de relativa e diminu iu com o aumento da temperatura máxima de maneira exponencial.As principais doenças de final de ciclo em arroz de terras altas incluem a brusone nas panículas [Pyricularia oryzae (Cavara) ] e a mancha de grãos associada a mais de um patógeno fúngico. (4,11,18,20). Keywords:Oryza sativa, volumetric spore trap, diseases of final growth stages, epidemiology. ABSTRACTGra in discolora tion (GD) is ra nk ed second a mong the most economically important rice diseases. The influence of nitrogen levels, planting date and air spora concentration on the disease severity was studied in the field. GD severity in the rice cultivar BRS Bonança was assessed on two planting dates (3 0/11/2006 and 21/12/2006), using five nitrogen levels (0 , 3 0 , 6 0 , 1 2 0 a nd 2 4 0 k g of N.ha -1 ) and a randomized split plot block design with three replicates. The effect of N level on GD severity was not significant. The correlation between GD severity a nd empty spikelets was positive a nd significa nt. T he fungu s popu la tion in the air (a ir spora ) wa s qu a ntified u sing the volu metric tra p Rotorod Sa mpler from pa nicle emergence to Silva...

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Section: Introductionunclassified

Influência da adubação nitrogenada, época de plantio e aerosporos sobre a severidade da mancha de grãos em arroz de terras altas

et al. 2011

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“…Such differences may be related to a combination of factors related to agronomic and environmental differences. In rice seeds grown in central Brazil, a two-year survey reported B. oryzae at incidence levels averaging 13.6% in the first year and only 1.6% in the second year across 22 rice varieties, suggesting a strong interannual variation (Malavolta et al, 2007).…”

Section: Discussionmentioning

confidence: 99%

“…Sporadic surveys have been conducted to identify Bipolaris associated with rice seeds produced in Brazil (Franco et al, 2001;Farias et al, 2007;Farias et al, 2011) but few attempted to identify Bipolaris at the species level (Malavolta et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Regional and varietal differences in prevalence and incidence levels of Bipolaris species in Brazilian rice seedlots

Meneses¹,

Farias²,

Caniela³

et al. 2014

Trop. plant pathol.

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A total of 722 rice seed lots were collected at six production regions of Rio Grande do Sul state during three consecutive seasons (2009/10 to 2011/12). For each seed lot, 200 seeds were assessed for the presence of Bipolaris spp. using a standard seed health blotter test. Results showed that B. oryzae and B. cynodontis were found in 62.5% and 10.4% of the seed lots, respectively. Overall mean incidence of B. oryzae and B. cynodontis were 0.5% and 0.06%, respectively. For the two most sampled varieties (75% of the seed lots), IRGA 424 and Puitá INTA CL, mean incidence levels were highest and lowest, respectively. Among regions, infection risk was highest in the southeastern and lowest in the western regions of the state, especially the Fronteira Oeste. The prevalence and the incidence levels of Bipolaris oryzae reported in this study were lower than previous reports in the same region -eighty percent of the seed lots showed incidence levels below the recommended 5% inoculum threshold. In conclusion, rice seeds produced by IRGA-certified growers showed an overall good health quality with regards to B. oryzae infection, which is the main Bipolaris species associated with rice seeds in southern Brazil.

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“…Malavolta et al (2007) reported that the severity of grain spots was negatively correlated with panicle weight and the number of filled grains, and positively with the number of void grains and percentage of sterility, thus affecting the main components of rice yield.…”

Section: Methodsmentioning

confidence: 99%

Variability of physical properties of soil and rice grown under cover crops in crop-livestock integrated system

et al. 2017

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AbstrAct:The production systems of upland rice culture in Mato Grosso are not consolidated yet while the effects of soil physical properties and their correlation with rice yield in crop-livestock integrated systems are not defined as well. Therefore, this study determined the spatial variability of physical properties of soil and rice cultivated in no-tillage system under different cover crops, using principal components analysis and geostatistics. The experiment was conducted in Santa Carmen, northern Mato Grosso. A regular grid with 100 sample points distributed in an area of 26,400 m² was installed. . The highest yields were observed in consortium with cowpea and brachiaria and were associated with lower incidence of grain spots, despite higher soil density and penetration resistance. The consortium with brachiaria, crotalaria, and sudangrass had lower yields, which was associated with higher incidence of grain spots, despite higher soil macroporosity and total porosity.

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Incidência de fungos e quantificação de danos em sementes de genótipos de arroz

Cited by 15 publications

References 1 publication

Influência da adubação nitrogenada, época de plantio e aerosporos sobre a severidade da mancha de grãos em arroz de terras altas

Influência da adubação nitrogenada, época de plantio e aerosporos sobre a severidade da mancha de grãos em arroz de terras altas

Regional and varietal differences in prevalence and incidence levels of Bipolaris species in Brazilian rice seedlots

Variability of physical properties of soil and rice grown under cover crops in crop-livestock integrated system

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