1^1^] Goodspeed: Germinaiion of Tobacco Seed 243 



1906 to 1912 seed in the case of 78/05 and 1905 to 1912 seed in the 

 ease of 110/05. is approximately 70 per cent, whereas the seed of 

 H 18 and H 20, five years old, germinated 89.5 per cent and 96.5 per 

 cent respectively. The five-year-old seed of 78/05 germinated 71.5 

 per cent in the 1913 test and 95 per cent in the 1914 test, while the 

 five-year-old seed of 110/05 germinated only 79.5 per cent. Compari- 

 sons between the germination of the seed of other N. Tahacum varieties 

 and that of the F^ seed of hybrids made between them are, some of 

 them, more significant (tables III. IV, and V). It is certainly re- 

 markable that the six-year-old seed of 68/07. 22/07, H 5 (22/07 X 

 68/07). and H 15 (68/07 X 22/07) should show almost exactly the 

 same duration of germination and that, for all four, the day upon 

 which maximum germination took place should be the same. Too 

 much emphasis cannot be laid upon the duration of germination in 

 this case, since the 1913 test of the 1909 22/07 seed showed this to be 

 eleven days as contrasted w4th three days for the 1914 test of this 

 same seed. Attention must, however, be called to the fact that the 

 important portion of the 1913 germination of the 1909 22/07 seed took 

 place within five days (cf. Goodspeed, I.e., p. 211), while the remain- 

 der of the seed that germinated after these five days accounts approxi- 

 mateh' for the difference between the total amounts of germination 

 of the five-year-old seed and the six-year-old seed of 22/07. Con- 

 trasted with the similarities in the duration of germination and the 

 day upon which germination took place in the greatest amount, we 

 have a distinct difference between the reciprocal hybrids, H 5 and 

 H 15, as to the total amounts of germination — i.e., 92 per cent for 

 H 5 and only 70 per cent for H 15. The seed produced by F^ of the 

 cross 78/05 X 72/05 and its reciprocal can. likewise, be distinguished 

 by differing amounts of total germination. Thus while the six-year- 

 old seed of the parents, 78/05 and 72/05, germinated 95 per cent and 

 93.5 per cent respectively, the 1909 seed of F^ H 7 (72/05 X 78/05) 

 germinated 77 per cent and corresponding seed of its reciprocal (F^ 

 H 8) germinated 97.5 per cent. It is also important to note that the 

 germination of 1909 72/05 is characterized by two maxima of germi- 

 nation — the sixth and the ninth day of the test — and that Fi 11 7. 

 also, shows maxima of germination — the seventh and the tenth day of 

 the test. As noted above, 72/05 is the female parent of the hybrid 

 H 7. Similarly, comparing the germination of 1909 F^ II 8 and 1909 

 78/05, the correspondence between the two is striking in that they 

 both have but one day of maximum germination, and thus that the 



