6 BULLETIN 1134, U. S. DEPARTMENT OF AGRICULTURE. 



Bolls were gathered in the fall from all 50 of the Acala (upland) 

 plants and from each of the 50 plants, opposite to these, in Pima 

 rows 1, 2, 3, 4, 6, 8, 10. 15, and 20, on the west and rows 1', 2', 3', 4', 

 6', 8', 10', 15', and 20' on the east of the upland. Each lot of seed 

 was thoroughly mixed, and a representative sample was planted in 



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20 



/S 



/O S 432/ O /'2'3'*' &' 0' SO' 



/S' 



20' 



Fig, 1. — Planting plan of an experiment to determine the extent of vicinism resulting 

 when plants of the Acala variety of upland cotton were located in the midst of a field 

 of the Pima variety of Egyptian cotton. The middle section of the central row 

 (row O), indicated by the dotted portion of the line, contained the upland plants, the 

 remainder of this row and the rest of the field having been planted to Pima. Hori- 

 zontal lines inclose the portions of the Pima rows from which seed was harvested for 

 determination of the percentage of vicinists. 



1921 in order to determine the percentages of vicinists. No thinning 

 was done, all seeds which germinated having been allowed to de- 

 velop. The results are stated in Table 2, in which the populations 

 grown from each pair of Pima rows having the same cardinal num- 

 ber and its prime, both east and west of the Acala section, are com- 

 bined as one array. 



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