Articles
KERNEL BREAKDOWN APPEARS WHEN HYBRID CASTANEA CULTIVARS ARE POLLINIZED BY CASTANEA MOLLISSIMA
Article number
1019_14
Pages
91 – 97
Language
English
Abstract
Chestnut rots are caused by various fungal species which infect the nuts during the growing season and may be indirectly involved with insect infestation of chestnuts.
Michigan-grown chestnuts appeared to have an internal decay or kernel rot problem.
Chestnuts from the Castanea sativa × C. crenata hybrid cultivar Colossal, widely planted throughout Michigan, have been the most susceptible while chestnuts from C. mollissima trees do not appear to be affected.
Thirty-to-forty percent of the chestnuts showed decay at harvest in some orchards growing Colossal trees while others showed very little or none.
A fungus or other infectious agent has not been isolated or observed microscopically despite many attempts over several years to culture or observe a causal agent.
We tested the hypothesis that the decay, which has been termed internal kernel breakdown (IKB), is a physiological problem promoted by particular pollen sources.
Female flowers from Colossal trees planted in three isolated plots in mid-Michigan were exposed to four pollen sources: Nevada (C. sativa × C. crenata); Precoce Migoule (C. sativa × C. crenata); Okei (C. crenata × C. pumila var. pumila); and Benton Harbor (C. mollissima), and a no-pollen control.
After the chestnuts were harvested, the kernels were observed for IKB symptoms.
No symptoms were found in chestnuts when Nevada or Precoce Migoule were the pollen sources; however, approximately thirty-five percent of trees pollinized by Benton Harbor showed IKB symptoms.
Only one percent of the chestnuts pollinized with Okei pollen showed IKB. Re-evaluating the Michigan chestnut orchards, we found that orchards without IKB-afflicted Colossal chestnuts had few or no C. mollissima pollen sources, and those orchards with Colossal chestnuts showing IKB were primarily utilizing pollen from C. mollissima seedlings or cultivars.
Michigan-grown chestnuts appeared to have an internal decay or kernel rot problem.
Chestnuts from the Castanea sativa × C. crenata hybrid cultivar Colossal, widely planted throughout Michigan, have been the most susceptible while chestnuts from C. mollissima trees do not appear to be affected.
Thirty-to-forty percent of the chestnuts showed decay at harvest in some orchards growing Colossal trees while others showed very little or none.
A fungus or other infectious agent has not been isolated or observed microscopically despite many attempts over several years to culture or observe a causal agent.
We tested the hypothesis that the decay, which has been termed internal kernel breakdown (IKB), is a physiological problem promoted by particular pollen sources.
Female flowers from Colossal trees planted in three isolated plots in mid-Michigan were exposed to four pollen sources: Nevada (C. sativa × C. crenata); Precoce Migoule (C. sativa × C. crenata); Okei (C. crenata × C. pumila var. pumila); and Benton Harbor (C. mollissima), and a no-pollen control.
After the chestnuts were harvested, the kernels were observed for IKB symptoms.
No symptoms were found in chestnuts when Nevada or Precoce Migoule were the pollen sources; however, approximately thirty-five percent of trees pollinized by Benton Harbor showed IKB symptoms.
Only one percent of the chestnuts pollinized with Okei pollen showed IKB. Re-evaluating the Michigan chestnut orchards, we found that orchards without IKB-afflicted Colossal chestnuts had few or no C. mollissima pollen sources, and those orchards with Colossal chestnuts showing IKB were primarily utilizing pollen from C. mollissima seedlings or cultivars.
Publication
Authors
D.W. Fulbright, S. Stadt, C. Medina-Mora, M. Mandujano, I.R. Donis-González, U. Serdar
Keywords
chestnut rot, chestnut quality, internal kernel breakdown, IKB, pollen
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