บทคัดย่องานวิจัย

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Detection of asymptomatic fungal infections of soybean seeds by ultrasound analysis.

Walcott, R. R.; McGee, D. C.; Misra, M. K.;

Plant Disease Year: 1998 Vol: 82 Issue: 5 Pages: 584-589 Ref: 15 ref.

1998

บทคัดย่อ

Detection of asymptomatic fungal infections of soybean seeds by ultrasound analysis.

Different levels of asymptomatic, seedborne infection by storage fungi (Aspergillus and Penicillium spp.) or Phomopsis seed decay (PSD) (caused by Phomopsis longicolla, Diaporthe phaseolorum var. sojae and D. phaseolorum var. caulivora) were induced in sub-lots of separate soyabean seed lots. Seeds or pods were incubated for different times at 25 deg C and at a RH of >95%. Seeds were then air-dried to a constant moisture content in the laboratory, and each sub-lot was tested for incidence of infection, germination, and moisture content. Individual seeds in each sub-lot were dropped 10 cm onto a transducer in an ultrasound analyser. The average peak value of the ultrasound signals for each sub-lot, which indicates the weight of seeds, decreased linearly as the incidence of seed infection by storage fungi or PSD increased. The slope and width of the signal, which indicates seed softness, increased as seed infection increased for both groups of fungi, although coefficients of determination were low

er. Germination values, which decreased as seed infection for both pathogens increased, showed similar but inverse relationships to ultrasound parameters. Peak values of ultrasound signals decreased, and slope and width increased, as seed moisture content increased for sub-lots of soyabeans at 3 levels of PSD infection. It is concluded that ultrasound technology has the potential to identify soyabean seeds with asymptomatic infections of seedborne pathogens.