North American Fruit Explorers mailing list at ibiblio

[William McNam <billmcnam@yahoo.com>]

This suggests the possibility of introducing more winter hardiness into ficus 
carica 


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Interspecific hybridization of fig (Ficus carica L.) and Ficus erecta Thunb., 
a source of Ceratocystis canker resistance 
H. Yakushiji, T. Morita, S. Jikumaru, H. Ikegami, A. Azuma and Y. Koshita
Abstract 
Ceratocystis canker, which is caused by the fungus Ceratocystis fimbriata 
Ellis et Halsted, is one of the most severe diseases of the common fig (Ficus 
carica L.). In contrast, the wild fig species F. erecta Thunb. is resistant 
to this fungus. 
We performed interspecific hybridization between the common fig (seed parent) 
and F. erecta (pollen parent) through artificial pollination. Even though 
hybrid seeds showed high germination rates, the seedling survival rates were 
low. All of the seedlings contained the expected simple sequence repeat (SSR) 
alleles from both common fig and F. erecta at each of the three loci tested, 
thus confirming the parent–offspring relationships of the interspecific 
hybrids. The leaf morphological characters of hybrid seedlings were 
intermediate between those of the parents. Cuttings of cultivars of common 
fig, F. erecta, and hybrid seedlings were inoculated with C. fimbriata by 
direct wounding of the shoot. All of the common fig cultivars tested withered 
and died within 10 weeks. Leaves and shoots of the hybrids and F. erecta were 
healthy 100 days after inoculation. Our results suggest that 
interspecific hybridization between the common fig and the wild species F. 
erecta is a breakthrough in the breeding of a new fig rootstock source with 
resistance to Ceratocystis canker.

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