FERTILIZATION IN PIMA COTTON. 7 



Table 2. — Vicinists yielded in 1921 by seed from plants of Acala cotton located 

 in the midst of a field of Pima cotton and by seed from those portions of suc- 

 cessive Pima rows which were opposite to and on both sides of the section of 

 Acala cotton, at Sacaton, Ariz., in 1920. 



Variety from which 

 seed was obtained. 



Plants. 



Fi hybrids. 



Variety from which 

 seed was obtained. 



Plants. 



Fi hybrids. 



Num- 

 ber. 



Per cent. 



Num- 

 ber. 



Per cent. 



Acala (upland), 1 row 0. . 



Pima (Egyptian): 



Rowsl and 1' 



Rows 2 and 2' 



Rows 3 and 3' 



Rows 4 and 4' 



/ 671 

 \ (714) 



635 

 615 



685 

 609 



93 

 (136) 



9 

 2 



4 

 



13.9±0.9 

 (19.1) 



1.4± .3 

 .3 



.6 

 .0 



Pima (Egyptian)— Con. 



Rows 6 and 6' 



Rows8and 8' 



Rows 10 and 10'... 

 Rows 15 and 15 ' . . . 

 Rows 20 and 20'. .. 



579 



456 

 >600 

 *600 

 »600 



1 

 

 

 



o 



0.2 



















1 Through an oversight, the seed from the Acala plants was planted in a plat in which upland cotton 

 had been grown in 1920. There were numerous volunteer plants, many of them first-generation upland X 

 Egyptian hybrids which could not be distinguished from the hybrids belonging to this experiment unless 

 they occurred outside the rows and hills of the 1921 planting. Consequently, it was deemed best to count 

 as vicinists belonging to this experiment only Fi plants which grew in hills with plants of Acala, exclud- 

 ing such Fi plants as occurred singly in a hill, even though their alignment and spacing distance con- 

 formed to that of the 1921 experiment. The figures obtained by including such plants are, however, given 

 in parentheses. It is probable that the first percentage given in the table is lower and the second higher 

 than the true percentage of vicinists yielded in this experiment. 



* Estimated. 



The percentage of vicinists yielded by the section of Acala plants 

 was at least ten times greater than that yielded by the Pima plants 

 which grew on either side of them (rows 1 and 1'). A considerably 

 higher percentage in the former case would be expected (1) because 

 the Acala was surrounded on all sides by Pima and (2) because dur- 

 ing the latter part of the season the Pima plants were flowering more 

 profusely than the Acala. But these factors alone do not seem ade- 

 quate to explain the much greater proportion of vicinism in the case 

 of the upland. It will be noted that no vicinism was detected in the 

 Pima cotton situated farther awav from the Acala than rows 6 

 and 6'. 



A 7-row plat of Pima cotton was grown at Sacaton in 1920 ad- 

 jacent to a 7-row plat of Durango (upland). Each row of each 

 variety was harvested separately. Each resulting lot of seed was 

 thoroughly mixed, and a portion of each lot was planted in 1921 in 

 order to determine the percentages of vicinists. No thinning was 

 done, all plants which germinated having been allowed to develop. 

 The results are stated in Table 3. 



Table 3. — Vicinists yielded in 1921 by plantings of seed from successive rows 

 in adjacent plats of Pima and Durango cottons grown at Sacaton, Ariz., in 

 1920. 



[No. 1 designates the adjacent row of each of the two varieties and No. 7 the row of each variety which 



was most remote.] 





Plantings of seed from Pima 

 (Egyptian) rows. 



Plantings of seed from 

 Durango (upland) rows. 



Row. 



Plants. 



Fi hybrids. 



Plant* 



Fi hybrids. 





Number. 



Per cent. 



Number. 



Per cent. 



No.l 



270 

 386 

 346 

 252 

 365 

 355 

 361 



9 

 8 

 10 

 4 

 2 

 3 

 5 



3.3±0.7 

 2.1± .4 

 2.9± .6 

 1.6± .5 

 .5± .2 

 .8± .3 

 1.4± .4 



255 

 313 

 288 

 313 

 233 

 286 

 288 



6 



10 

 2 

 2 

 7 

 2 

 4 



2.4±0.6 



3.2± .7 

 • 7± .3 

 .6± .2 



3.0± .8 

 .7± .3 



1.4± .5 



No. 2 



No. 3 



No. 4 



No. 5 



No. 6 



No. 7 





Total 



2,335 



41 



1.8± .2 



1,976 



33 



1.7± .2 





