RESULTS OF COTTON EXPERIMENTS IN 1911. 17 



The large size of the i)lants increases the labor of picking, and much 

 of the crop is lost by the breaking down of the branches between the 

 rows. These are the most serious difhculties in the development of an 

 Egyptian cotton industry in the irrigated districts of Arizona and 

 southern California. 



When the Egyptian cotton is grown under conditions that do not 

 induce luxuriant growth the behavior is much like that of Uplan<l 

 -cotton. The plants arc low and spreading, with open foliage, and 

 the bolls develop about as rapidly as those of Upland cotton. Tliis 

 Uphmdlike behavior has been observed when the Egyptian cotton 

 was grown in cool climates, as in the vicinity of Wasliington, D. 0., 

 and near Los Angeles, Cal. This is also the normal behavior of the 

 plant in the lower part of the Nile Valley, where most of the Egyp- 

 tian cotton is raised. The temperatures are kept low by the north 

 winds that regularly blow in from the Mediterranean. 



Early planting has been advised in California as a means of restrict- 

 ing the development of the vegetative branches, because fewer 

 branches are produced during the cooler weather of early spring. 

 But the advantage that may be gained in tliis way is easily lost, for 

 a sudden access of warm weather is likely to throw the plants into 

 luxuriant gTOwth and induce the development of vegetative branches 

 from all of the lower joints of the stalk. 



Apart from the influence of cold weather in keeping the plants 

 from becoming too luxuriant, experiments have shown that there 

 are two other factors, moisture and exposure to sunlight, that govern 

 the development of vegetative branches. Plants that grow from the 

 outset in dr}^ soil, even though standing alone and fully exposed to 

 high temperatures and to full sunlight, often fail to develop any 

 vegetative branches, but begin to produce fruiting branches only a 

 few inches from the ground. Wlien cotton is grown under irrigation 

 it is possible to restrict the production of vegetative branches by 

 withholding water in the early part of the season until the fruiting 

 stage is reached. 



The development of vegetative branches is also restricted when 

 the plants stand close together so as to shade the lower joints of the 

 main stalk, which produce most of the vegetative branches. If the 

 plants are tliiimed too early, so that the lower joints are exposed 

 before there is enough foliage to keep them shaded, vegetative 

 branches are likely to be put forth at each joint and even from the 

 axils of the cotyledons or seed leaves. But if the plants are allowed 

 to stand closer together or are thinned gradually they may not pro- 

 duce any vegetative branches. 



There are ob^aous limitations, of course, in the use of dryness and 

 shading to prevent the development of vegetative branches. If the 



[Cir. 96] 



