BUKEAU OF PLANT INDUSTRY. 163 



•erected at a cost of about $20,000,000 by a company that has invested 

 a similar amount of capital in the production of Pima cotton. 



Cotton possibilities of California. — The results of the season of 

 1919 confirm the indications of previous j^ears that the Pima va- 

 riety of Egyptian cotton can be grown in the San Joaquin Valley 

 even to greater advantage than in the more southern valleys. In 

 spite of the earliest killing frost in many years, which occurred 

 on October 27, 1919, yields of a bale per acre were secured from 

 good fields. The behavior of the plant is more regular and normal 

 than in the hotter valleys, with larger numbers of bolls matured 

 earlier in the arowing season on the lower fruiting branches. It 

 is estimated that the San Joaquin Valley contains at least 1,000,000 

 acres of land from which normal crops of Pima cotton might be 

 expected. Outside of the range of Pima cotton, good results may 

 still be secured from some of the Upland varieties, and especially 

 from Durango, Acala, and Lone Star, so that estimates of 2,000,000 

 or even 3,000,000 acres of cotton land in California are not con- 

 sidered excessive. Communities that limit themselves to a single 

 superior varietj^ so that pure stocks of seed can be maintained, will 

 have a further advantage in being able to supply seed for Texas 

 or other States of the eastern cotton belt, especially in seasons when 

 seed of planting quality is scarce, as in the spring of 1920. 



Ttuo Idnds of cottan branches. — A beneficial control of the growth 

 of cotton is made possible because the plant produces two distinct 

 kinds of branches. The branches that develop from the lower joints 

 of the main stalk have only vegetative functions and are entirely 

 different from the fruiting branches, where the flowers and bolls 

 are produced. That the two kinds of branches are distinct and 

 that the vegetative branches need to be suppressed in the interest 

 of early fruiting are fundamental facts in relation to many prob- 

 lems of breeding varieties of cotton and improving cultural meth- 

 ods. To make possible a full application of the results of scientific 

 discovery in the handling of this important crop, the distinct struc- 

 tures and functions of the two kinds of branches need to be recog- 

 nized by teachers, experiment-station workers, farm advisers, and 

 writers of textbooks, as well as by practical farmers. 



Control of branching in cotton. — For controlling growth and sup- 

 pressing vegetative branches, improved methods of thinning and 

 spacing have been devised and are now being applied. Instead of 

 " chopping out " the very young cotton as soon as the seed leaves 

 have opened, tliinning is deferred until the plants are 5 or 6 inches 

 high, or until the first fruiting branches begin to develop, with the 

 small " forms," or " squares," that inclose the floral buds. And 

 instead of the wide spacing formerly considered advisable, earlier 

 and larger crops are being secured from plants 4 to 10 inches apart 

 in the rows. The closer spacings are needed where there is more 

 danger of rank growth and excess of vegetative branching. Spacing 

 to tlie width of the hoe is becoming a popular standard, especially 

 if the precaution of not thinning too early is observed. In open, 

 scattei'ing stands, with the plants averaging 3 or 4 inches apart in 

 the rows, the labor of thinning may be saved, since no advantage 

 may be secured. 



Open lanes between cotton rows. — The S3'stem of controlling the 

 growth and branching of the young plants was first worked out in 



