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A histological examination of “white knot” disorder in tubers of the cultivar Atlantic


A histological examination of a disorder known as “white knot” or “starch spot” was carried out on affected tubers of the potato cultivar Atlantic. Results revealed that the hard white lump located just below the periderm in affected tubers was comprised of cells containing a high number of starch granules, 2–4 times larger than those found in unaffected areas of the tuber. In the province of Ontario, “white knot” appears to be more prevalent in seasons when specific gravity is high.


Se llevó a cabo un examen histológico del desorden conocido como “nó-dulo bianco” o “mancha amilácea” sobre tubérculos afectados del cultivar de papa Atlantic. Los resultados revelaron que los terrones duros y blancos localizados inmediatamente debajo de la peridermis de los tubérculos afectados comprendían células conteniendo un gran número de gránulos de almidón, dos a cuatro veces el tamaño de aquellos encontrados en zonas no afectadas del tubérculo. En la provincia de Ontario, parece ser que el “nódulo bianco” prevalece más en las temporadas en que la gravedad específica es alta.

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Keenan, M.K., Baker, K.W., Coffin, R. et al. A histological examination of “white knot” disorder in tubers of the cultivar Atlantic. American Potato Journal 66, 489–493 (1989).

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  • Specific Gravity
  • AMERICAN Potato Journal
  • Starch Granule
  • Potato Cultivar
  • High Specific Gravity