Van Fleet: Chestnut Breeding Experiences 



21 



A HYBRID CHINQUAPIN 



These nuts are produced by a seedling which was grown 

 from the cross between the shrubby American chin- 

 quapin and the Japanese chestnut. Three nuts are 

 usuaUy borne in each bur, and they are larger in size 

 than those produced by any of the native American 

 species. Photograph natural size. (Figure 10 ) 



The bark disease has been allowed 

 to work its will among the hybrids with 

 the result that trees having C. ameri- 

 cana in any combination have nearly 

 all disappeared. Seedlings of Paragon 

 chestnut, the best variety of the 

 European type, pollinated with our 

 native species, attained an average 

 height of twenty-five feet and were 

 bearing excellent nuts when attacked 

 in 1910, but all have succumbed. The 

 crosses of Asiatic and native, fewer in 

 number, showed greater resistance but 

 all have been seriously affected. The 

 chinquapin-European hybrids are readily 

 affected but have great recuperative 

 powers, bearing nuts the second year 

 on suckers springing from the bases of 

 diseased stems. Chinquapin-native 

 crosses, with the exception of the Rush 

 chinquapin — a probable natural hybrid 

 found wild in Pennsylvania — appear 

 very susceptible and do not as readily 

 recover. The wild chinquapin itself ap- 



pears measurably resistant, several in- 

 dividuals, including two Rush chinqua- 

 pins, thriving for years with no signs of 

 disease though constantly surrounded 

 by infection. 



The Asiatic chestnuts, and the 

 chinquapin- Asiatic hybrids, are plainly 

 highly resistant. Few have shown any 

 appearance of infection and when 

 noticeable the injury is quite local in 

 character. Second generation seedlings 

 of chinquapin-crenata crosses show no 

 disease at all though always exposed to 

 infection. 



QUALITIES OF HYBRIDS 



The material results of this breeding 

 work, other than the disease-resisting 

 features, are shown in the various 

 illustrations accompanying this article. 

 Hybrid chinquapins having varieties 

 of Castanea crenata for the pollen parent 

 form vigorous, small, much branched 

 trees, rarely shrubs, and come into 



