Incidence of Sclerotinia sclerotiorum and the physical and physiological quality of soybean seeds based on processing stages

Abstract

Soybean (Glycine max L. Merrill) is infected by a large number of fungal pathogens, among them white mold agent [Sclerotinia sclerotiorum (Lib) de Bary]. The objective of this study was to verify the effect of the seed-processing stages on the physical and physiological qualities and on the incidence of S. sclerotiorum in soybean seeds. In this study, seeds from eight cultivars coming from production fields naturally infested in the counties of the State of Goiás, Brazil, from two harvests (2009/2010 and 2010/2011), were used. Samples were collected in the processing stages: hopper, pre-cleaning, discard one (from pre-cleaning), cleaning, sieve classifiers, spiral, gravity table, and discard two (after cleaning until processing ending). The following parameters were evaluated: seed- moisture content, physical purity, germination and tetrazolium. Additional tests and the detection of S. sclerotiorum in paper roll and the neon method were performed. The processing of soybean seeds improves the physical and physiological quality of the seed lots, in addition to eliminating sclerotia. The stages of pre-cleaning and cleaning significantly reduce sclerotia in seed lot. The amount of sclerotia in the sample is not necessarily correlated with the incidence of S. sclerotiorum in mycelial form.

Partial resistance of soybean lines to asian rust and white mold

“…In studies carried out in the field by Garcia, Juliatti (2012) and Juliatti et al (2013), the genotype Emgopa 316 was also considered resistant to the disease when compared to other genotypes. In a study conducted in the crop season 2010/ 2011 using cultivar NA 7255 RR, Teles et al (2013) observed a higher incidence of sclerotia in seed samples. The same author reported that the amount of sclerotia in the sample was not necessarily correlated with the incidence of S. sclerotiorum in the mycelial form in soybean seeds.…”

Inoculação de Sclerotinia sclerotiorum em sementes de oleaginosas: transmissão e seus efeitos sobre a emergência de plantas

“…O bom desempenho de uma cultura depende da qualidade das suas sementes, pois elas contêm todo o potencial genético que a planta pode expressar (MENEZES et al, 2011 No Brasil, tem-se verificado a preocupação com relação à infecção das sementes por micélio de S. sclerotiorum (HENNEBERG et al, 2012;BOTELHO et al, 2013;TELES et al, 2013), todavia, a taxa de transmissão do patógeno, para muitos de seus hospedeiros, ainda não foi quantificada, tampouco, tem-se relacionado a infecção fúngica com o vigor de sementes e desenvolvimento de plantas. Diante do contexto, o trabalho propôs-se a verificar a transmissibilidade de S. sclerotiorum a partir de sementes de canola, cártamo, crambe, girassol, nabo forrageiro e níger, inoculadas artificialmente, às suas plântulas, assim como avaliar a sua relação e implicação sobre a emergência de plântulas.…”