Detlefsen and Ruth : Chestnut Hybrids 



311 



NUTS FROM THE SECOND GENERATION TREES 



Figure 12. These nuts show further variations in the second generation. The 

 three on the left are acorn-shaped, being from trees that produced but a single nut in 

 a burr. The two on the right are nearly the same size, but they are flat on one side and 

 the amount of tomentum is very much less on one than on the other. See text, p. 314. 



plant improvement. Born in 1839, he 

 was 60 years old when he made his 

 first successful chestnut species cross. 

 He was 70 years old when he planted 

 a large orchard of over 150 F^ trees. 

 He died in 1914 without seeing the 

 final results of the second generation 

 of his interesting cross. In choosing 

 the Japanese and the American sweet 

 for hybridization, Mr. Endicott prob- 

 ably had in mind the combination of 

 certain very desirable characters from 

 each parent. He had a large number 

 of American sweet chestnuts growing 

 on his land, but he wished to im- 

 prove them, for he recognized their 

 shortcomings as well as their desir- 

 able qualities. The Japanese type has 

 the advantages of a large nut lying 

 free in a relatively smaller burr, is 

 rather resistant to weevils, blooms 

 and matures early, and has a nut with 

 more attractive color and less to- 

 mentum ; while the American type 

 has three small nuts very tight in 

 the burr, is susceptible to weevils, 

 blooms and matures later, and has 

 nuts of poor color and heavy tomen- 

 tum. The American sweet, however, 

 has nuts of fine quality with a thin 

 skin, grows vigorously and produces 

 a large tree, whereas the Japanese 

 has poorer quality (at least in many 

 cases), a thick skin, and produces a 

 low bushy tree of delicate growth. A 

 combination of the desirable features 

 from these two sources naturally rec- 

 ommended itself to Mr. Endicott and 

 therefore he attempted to make the 

 cross. 



He seemed to have some difficulty 



in the routine technique, for the Jap- 

 anese and the American sweet differed 

 in time of blooming. Eventually he 

 produced five hybrid seeds from which 

 he raised three trees, naming them 

 the Blair, the Boone, and the Riehl. 

 As we might expect, the three trees 

 of the first generation were not all 

 exactly alike, for 'thfe. parents (at least 

 the Japanese) were more or less 

 heterozygous. xA.s' a matter of fact, it 

 is surprising that the three trees were 

 as nearly similar "as we found them. 

 Like the American sweet, the Blair 

 and Boone produced three nuts to the 

 burr, while the Riehl produced a 

 single perfect nut with an aborted 

 nut on each side like the Japanese 

 parent. All three first generation hy- 

 brids produced nuts free in the burr 

 like the Japanese parent. All of these 

 trees showed tremendous vigor (Fig. 

 7.) The largest, the Riehl, had a 

 spread of forty-five feet when twenty 

 years old. The Blair and Riehl be- 

 gan to bear at four and five years, 

 respectively, while the Boone bore 

 its first nuts at seventeen months. 

 When we compare this with the Jap- 

 anese and the American parents, which 

 begin to bear at about six and twelve^ 

 years, respectively, we gain some idea 

 of the precocity which accompanied 

 the hybrid condition. Van Fleet* re- 

 ports similar vigor in crossing Asiatic 

 and European chestnuts with the chin- 

 quapin and the American sweet — the 

 Japanese hybrids being again the 

 most precocious. These hybrids were 

 likewise heavy bearers, the Boone 

 producing as much as six bushels in 



