4 CIKCULAR NO. 121, BUREAU OF PLANT INDUSTRY. 



The most essential step in connection with a long-staple cotton 

 industry is the establishment and maintenance of clean and select 

 seed of the variety. Deterioration of a variety from failure to select 

 the seed or through carelessness in keeping it free from mixture with 

 seed of other varieties can not be overcome by cultural or other 

 methods. The cotton industry of the Imperial Valley will be best 

 served if proper means are taken during the season of 1913 to insure 

 a supply of select, pure Durango seed for planting in 1914. 



CLEAN SEED FOR PLANTING IN 1914. 

 MIXED SEED SHOULD BE DISCARDED. 



The great promise of the Durango variety has led the cotton 

 growers to plant this year all available seed, though it is known that 

 a large proportion of it is mixed or impure and can be used only for 

 a single season. 



At least three-fourths (or about 4,500 acres) of the Durango cotton 

 acreage in the Imperial Valley m 1913 will be planted to seed which 

 was grown in the valley in 1912. Unfortimately, this seed has been 

 mixed and cross-pollinated with short-staple cotton. The seed 

 planted in 1912 was grown in the valley in 1911 on clean land which 

 had been in alfalfa the preceding season, so that no mixture occurred 

 in the field. A small amount of mixture (possibly 2 to 4 per cent) 

 occurred in the ginning of the Durango seed in 1911. The mixing 

 probably took place in the screw conveyor which carries the seed 

 from the gin stands to the wagon. 



The most serious mixture occurred in the fields in 1912. A large 

 part of the Durango cotton was planted on land which had been in 

 short-staple cotton in 1911, and the volunteering of the previous 

 season's variety caused an actual mixture of short-staple plants in 

 the Durango fields amounting to cS to 20 per cent. This has resulted 

 not only in an actual seed mixture in the crop produced in 1912, but 

 also, and what is even more serious, in the hybridization of the Durango 

 with short-staple cotton. Either sort of mixture, if allowed to 

 persist, would prove disastrous to the new long-staple industry. 

 Seed mixture alone in stocks of valley seed might be successfully 

 overcome, but the cross-pollination of the Durango by short-staple 

 varieties is a mixture practically impossible to eradicate. While 

 some of the valley Durango seed to be planted in 1913 contains not 

 more than 5 per cent of short-staple seed, the hybridization which 

 has taken place makes it essential for the eventual good of cotton 

 growing in the Imperial Valley that all mixed seed be sent to the oil 

 mill or some other seed-destroying agency this fall, so that no stock 

 of mixed Durango seed can be planted in 1914. 



ICir. 121 J 



