Heartnut and Butlermil Hybrids 



The Japanese heartnut, Juglans sieboldiana, a winter hard) and a fast- 

 growing tree at Durham, somewhat resembles the native butternut. J. cinerei. 

 In the spring of 1951, Radcliffe Pike, graduate student in the Horticulture 

 Department. University of New Hampshire, pollinated a heartnut at the 

 Horticultural Farm with pollen from one of the best native butternuts in the 

 station plantings. In the fall of 1956, 8 or 10 nuts were harvested from a 

 hybrid tree then only 4 years old. Only pistillate flowers were produced by 

 this hybrid tree in the spring of 1956. Some wild butternuts grow about 75 

 yards from the spot where the hybrid tree stands in a private garden in 

 Rochester, New Hampshire. It is thus assumed that these nuts should give 

 a backcrossed progeny and it has been possible to grow two such seedlings 

 for field planting in 1957. Also in 1957, the F^ tree again bore only pistillate 

 flowers, so it has been possible to obtain more backcrossed nuts for planting. 

 The hybrid tree, sometimes called a "buartimt", is vigorous and not subject 

 to leaf troubles, though it is attacked by lace-winged insects similar to the 

 parental species. There may be possibilities for improvement of the native 

 butternut through this breeding approach. When 4- or 5-year-old trees can 

 1)6 fruited, progress can be made seemingly as fast as with the peach. Methods 

 for propagation of any new selected nut will have to be worked out. Butter- 

 nuts are propagated vegetatively with some difficulty. 



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