1919] FIELD CROPS. 527 



Arizona-Egyptian, together with notes on the production of long staple cotton 

 in California, Brazil, and Peru. 



'Brief in behalf of the Louisiana Farmers' Association, G. E. Cum Kit 

 (Shreveport, La.: La. Fanners' Assoc, 1918, pp. 13). — The total cost of pro- 

 duction of cotton in Louisiana in 1918 for a 40-acre unit, Including land rent, 

 mule rent, feed, man labor, fertilizer, seed, etc., is estimated at $2,0G7 and 

 the net cost of production at 32 cts. per pound. 



A study of hybrids in Egyptian cotton, T. H. Kkaknky and \V. G. Wk.u.s 

 (Amer. Nat., 52 (1918), No. 622-628, pp. 1,91-506. figs. 3).— Investigations began 

 in 1914 at Sacaton, Ariz., dealing with the conditions under which mutants 

 occur in Egyptian cotton, are described. Simple and back-crossed hybrids 

 have been made between Pima and Gila (E. S. R., 31, p. 525), and three genera- 

 tions of the hybrid progenies, and of progenies from selfed seed of the parent 

 stocks, have been grown. 



No evidence of the appearance of new characters has been observed in any 

 of the progenies, but since mutants in Egyptian cotton are comparatively rare, 

 it is deemed desirable to examine much larger populations before drawing 

 definite conclusions. It is stated that the principal interest attaching to the 

 data thus far obtained has to do with the behavior of hybrids between 

 varieties belonging to the same general type as compared with that of hybrids 

 between different species of Go&syptam, which have hitherto been the chief 

 subject of genetic studies with cotton. 



" The varieties used in this investigation are distinguished chiefly by size 

 and shape characters, although a few of the characters in which they differ 

 significantly have been found to behave as allelomorphs in hybrids between 

 less nearly related forms of Gossypiuni. The Pima X Gila hybrids, however, 

 showed no evidence of segregation in definite ratios in respect to any of the 

 characters measured. There was little or no evidence of dominance in the 

 Fi, and the F a distributions were practically without exception unimodal. The 

 means of the simple hybrid were in most cases intermediate between those of 

 the parents. The result of twice back-crossing the simple hybrid upon either 

 parent was to obliterate the expression of the characters of the other parent. 



" It could not be demonstrated that genetic correlation or coherence of char- 

 acters occurs in these hybrids. Apparently all characters which are not cor- 

 related physically or physiologically are transmitted independently. The second 

 and third generations of the hybrids, as compared with the parents after two 

 and three generations of selfing, were not more variable than Gila, and were 

 only a little more variable than Pima. This fact is of practical importance in 

 cotton breeding, since it points to the possibility of obtaining relatively stable 

 and uniform recombinations of the desirable characters of varieties belonging 

 to the same general type, although breeders have found this to be well nigh 

 impossible in wider crosses such as those of Egyptian (or Sea Island) with 

 upland cotton." 



Notes on fiber produced from some of the most useful indigenous and 

 exotic plants in the Cape Province, J. Lkighton (So. African Jour, get., Ik 

 (1918), No. 10. pp. 448, kkk)- — The author presents brief notes on the relative 

 values of the fibers produced by the more important indigenous and exotic 

 plants in the region. 



Investigations on hops (Humulus lupulus). — XI, Can different clones be 

 characterized by the number of marginal teeth in the leaves? J. Schmidt 

 (Compt. Rend. Lab. Carlsberg, U (1918). No. 2. pp. 23, figs. 8).— This is a fm- 

 ther contribution to the author's investigations With hops (E. S. R., 89, p. 234 ». 

 and comprises a study of differences observed in the number of marginal teeth 



