FIELD CROPS. 37 



small patch aud the experimenter's variety test. Tliis arises from the fact that 

 the variety is too frequently judged either on the basis of a single year's per- 

 formance and before local adjustment could possibly have taken place, or with- 

 out the selection necessary to remove the divergent individuals and restore 

 the former uniform excellence. Local adjustment applied in such instances 

 shows marked improvement in quantity and quality of fiber as well as in 

 uniformity of plants during the first few years after introduction into a new 

 locality. 



Correlated characters have been observed to change in accordance with their 

 usual laws during local adjustment in at least two instances. At Yuma, Ariz., 

 in 1908. upland cottons showed a general tendency to small round bolls and an 

 equally general tendency to shortening of the lint, which usually accompanied 

 this character. At Del Rio, Tex., in 1908, several selections showed increased 

 luxuriance of vegetation accompanied by inferior lint as compared with the 

 crop of 1907. 



The utilization of local adjustment in the introduction of new varieties is 

 essentially a matter of selection to restore the variety's uniform excellence and 

 is completed when that end is attained. The usual precautions are to be ob- 

 served with reference to a mixture of pollen by insects or of seed at the gin 

 in order to maintain the purity of the variety. 



The wide introduction of a few varieties of known excellence is recommended 

 to displace the present multiplicity. This will bring about uniformity in the 

 crop and simplify the problems of grading, marketing, and manufacturing. 



A study of diversity in Egyptian cotton, O. F. Cook, A. McLachlan, and 

 R. M. Meade (U. S. Dept. Agr., Bur. Plant Indus. Bui. 156, pp. 60, pis. 6).— This 

 bulletin points out the relationship of Egyptian cotton to American varieties, 

 discusses the nature of diversities aroused by new conditions, calls attention to 

 the diversity of recognized Egyptian varieties, and discusses the relation be 

 tween diversity and external conditions and the occurrence of diversity in 

 Egyptian-Upland hybrids. In this connection the frequencj' of cross-fertiliza- 

 tion, the distinctive characters of hybrids, the principal characters for dis- 

 tinguishing hybrids, and the correlations of characters in such plants are also 

 considered. A synopsis of the principal types of hybrids is given. 



It is stated that the Egyptian and Upland cottons belong to the same general 

 series of American types and are capable of showing similarly wide ranges 

 of diversity, especially when grown under new conditions. Egyptian varieties 

 grown at Yuma from imported seed show many forms of diversity and in 

 plantings of Arizona-grown Egyptian seed this diversity appears to have in- 

 creased even after all individuals distinguishable as hybrids have been ex- 

 cluded. The authors believe that the difficulty of acclimatizing Egyptian cot- 

 ton is increased by the fact that the varieties have been distinguished by their 

 lint characters alone with little or no reference to the vegetative features. It is 

 stated that selection for long lint has not reduced the diversity of forms and that 

 the crossing of these varied forms with each other tends to prolong the condi- 

 tion of diversity. It is recommended that for the purpose of securing prompt 

 acclimatization, selection should have reference to the normal behavior of the 

 plants rather than to new characters, or to especial excellence in particular 

 characters. 



It was found that incomplete acclimatization renders the plants unusually 

 susceptible to differences of external conditions and this is explained by the 

 facts that fertility and early bearing depend upon the habits of branching 

 which the individual plants may adopt and that these habits are readily in- 

 fluenced by environment. The appearance in the Egyptian fields of numerous 

 hybrids between the Egyptian varieties and the Upland varieties is the source 



