1918.] FIELD CEOPS. 533 



tion of certain crosses between types of cotton differing in the number of bract 

 teetli are reported. 



Frequency polygons of sucli difCereut forms as Sea Island, St. Croix Native, 

 Upland, and Cauto implied differences in gametic composition in respect to the 

 character of bract teeth. The Fi generation of two crosses, involving types dif- 

 fering in the number of bract teeth, showed complete dominance of the larger 

 number of teeth, while the Fi generation from a third cross exhibited an in- 

 tensification of the character, having a larger number of teeth than either 

 parent. Since certain types are known to have bracts entirely free from teeth, 

 it is deemed possible to secure at least six homozygous types differing con- 

 stantly in the number of teeth, and consequently at least three factors may be 

 concerned in determining the tooth character of a type possessing the highest 

 number. 



Inheritance of oil in cotton, E. P. Humbert (Science, n. ser., 45 (1917), No. 

 1165, p. 411). — Ether extractions of the seed from seven mother plants are re- 

 ported, giving the oil percentages. This is followed by an analysis of the seed of 

 their progeny plants for three progeny years, to show the possibility of produc- 

 ing divergent strains or biotypes from a " variety " of cotton, the one having a 

 relatively high oil content and the other a relatively low oil content. 



The three " high " parents showed an average of 19.51 per cent oil and their 9 

 progeny an average of 20.72 per cent. The four " low " parents had an average 

 of 16.89 per cent oil and their 12 progeny an average of 18.2 per cent. The 

 maximum differences between the parent plants and between the progeny plants 

 were 4.06 and 4.94 per cent of oil, respectively. Seasonal variations raising the 

 oil content of all progeny plants are noted. 



Cotton varieties in Georgia. — Variation of the oil content of cottonseed 

 and resistance to disease, L. E. Rast {Bui. Ga. State Col. Agr., No. 121 (1917), 

 pp. 36, figs. 12; ahs. in Science, n. ser., 45 (1911), No. 1169, pp. 507, 508).— A 

 number of variety tests in different parts of the State are reported, with special 

 reference to early maturity and disease resistance. Toole appeared best adapted 

 to conditions in the southern portion of the State, while College No. 1, Trice, 

 Cook, Hooper, Sunbeam, Cleveland Big Boll, Texas Bur, Culpepper, Caldwell, 

 Meadow, Brown No. 2, Williams, and Lankford are deemed best for northern 

 conditions from the standpoint of earliness. In testing varieties for resistance 

 to anthracnose it was observed that the disease affected both small and prac- 

 tically mature plants, although the greatest injury occurred to the bolls just 

 before they opened. 



Three years' observations of the oil content of the seed of different varieties 

 has led to the conclusion that marked differences exist between varieties in this 

 respect, these differences remaining fairly constant, and being transmitted from 

 generation to generation. The varieties showing the highest oil content when 

 grown on the college farm for a 3-year period were Rexall, Hite, Willet Perfec- 

 tion, Cook, and Willet Ideal, with 23.3, 22.55, 22.38, 21.94, and 21.78 per' cent, 

 respectively. Lankford and Caldwell, with oil contents of 18.88 and 19.93 per 

 cent, respectively, were lowest. Marked variations were also found to exist in 

 the oil content of seed from different plants of the same variety. 



History, development, and botanical relationship of Egyptian cottons, 

 G. C. Dudgeon (]\lin. Agr. Egypt, Agr. Prod. No. 3a (1916), pp. VIII+77, pis. 

 12). — An extended historical and botanical study of Egyptian cottons is pre- 

 sented, with tables showing the areas, yields, and average prices for cotton from 

 1820 to 1916, and the distribution of varieties from 1905 to 1916 by area and 

 percentage of total area. A bibliography of 71 titles is appended, comprising the 

 literature cited. 



Results of fertilizing experiments with cotton at the Clemson. CoUeg'e sta- 

 tion, T. E. Keitt (South Carolina Sta. Bui. 191 (1917), pp. 3-11). — In a con- 



