results of cotton experiments in 1911. 13 



importance of breeding varieties with distinctive 



characters: 



Since tho value of a superior variety depends very largely upon the 

 preservation of uniformity after it has been introduced into cultiva- 

 tion, means of maintaining uniformity must be taken into account in 

 breeding. Varieties with distinctive peculiarities, especially in the 

 vegetative ])arts of the ]>lants, are more valuable because it is easier 

 to detect and remove undesirable iniUvidual vaiiations that would 

 otherwise destroy tho uniformity of the stock. Prehu-encc is being 

 given to the breeding of new varieties that have readily distinguishable 

 characteristics, and the distinctive characters of existing varieties 

 are being determined in order to give a better basis for selection. 



The big-boll long-staple selection bred by IVfr. Saunders in Texas, 

 as already stated, has foliage of a slightly paler green than other varie- 

 ties of Upland cotton. Plants with darker foliage are always found 

 to depart fnmi the ty\)0, in other respects, having smaller bolls and 

 shorter and less abundant lint. The difference in color makes it easier 

 to recognize and remove from fields or breeding plats such vaiiations 

 of this pale-leaved strain. 



Seedlings of numerous varieties of Egy]:)tian and Upland cotton have 

 been compared with a view to the development of methods for detect- 

 ing undesirable variations in the early stages of growth. It has been 

 found that the Hindi variations of Egyptian cotton can be recognized 

 immediately after germination by differences of the cotyledons or 

 seed leaves. Those of the Hindi cotton are larger and smoother, are 

 marked with red along the vems, and have a reddish callus at the base. 



Differences in the forms of the first series of true leaves also permit 

 some of the varieties to be (Hstinguished in the early stages of growth. 

 Egyi^tian varieties usually have five or six simple leaves at the base 

 of the stalk before the lobed leaves begin to appear. Upland varieties 

 have fewer simple leaves and some show lobed leaves from the first. 

 The involucral bracts that inch^se the flower buds afford another 

 series of characters of use in distinguishing varieties. 



JUVENILE LEAF-CURL OF COTTON. 



Malformation of the leaves is a widespread disorder of young cotton 

 seedlings. Many of the seedlings with malformed leaves also lose the 

 terminal bud. This disorder forces the development of vegetative 

 branches from the axils of the cotyledons and from other jomts at the 

 base of the stalk. Though such plants always recover, in the sense 

 that they afterwards pnxUice normal leaves, flowere, and bolls, they 

 are more or less misshapen, mature later than uninjured plants, and 

 produce a smaller crop. Retarded and irregular growth is particu- 



[Cir. 9G] 



