Chestnut Callus-Cultures: Tannin Content and Colonization by Endothia parasitica

Five clones of callus tissue cultures were obtained using scions of chestnuts that represented a gradient of blight resistance, from susceptible to resistant. These were, respectively, Castanea dentata (susceptible), C. dentata ("resistant"), an offspring of an open-pollinated Japanese X American, C. crenata, and C. mollissima. The growth rate (fresh weight) and time-course of tannin production (galloyl esters, ellagitannins, and condensed tannins) were determined in the five clones under two light regimes. Generally, the more blight-resistant the source of cultures, the more galloyl esters and ellagitannins the culture contained. Only cultures from the two most blight susceptible sources contained significant amounts of condensed tannins. The differences among the hydrolyzable tannin levels of the callus tissue cultures of the five types of chestnut appear to be an excellent index of the blight resistance. The degree of colonization of callus of each clone by a hypovirulent E. parasitica was less than that by a virulent E. parasitica. However, the degree of colonization of the callus tissues was not correlated with the blight resistance of the parent trees. Possible reasons for this variation were differences in callus morphology and in the rate of senescence of the calli, which altered tannin levels.

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Author(s): Frederick V. Hebard, P. B. Kaufman

Publication: American Chestnut Proceedings - 1978