POLLINATION AND STERILITY 



309 



Anjou, Lawrence, Duchess, and Kieffer are satisfactoiy va- 

 rieties for planting with Bartlett so far as pollination is con- 

 cerned. Some years Kieffer does not blossom simultaneously 

 with Bartlett, but usually the blossoms overlap sufficiently. 

 Le Conte, Garber, Lawrence, Bartlett, Duchess, Anjou, and 

 Clairgeau are satisfactoiy varieties for planting with Kief- 

 fer, so far as pollination is concerned. Some seasons the 

 latter five varieties do not blossom simultaneously with 

 Kieffer, but usually the blossoming seasons overlap suffi- 

 ciently." 



He obtained the following results under Virginia condi- 

 tions: 



Table LXXXVIII 



In Califoniia the Bartlett is grown very extensively and, 

 in spite of the advice given to the growers to inter-plant 

 with other varieties, there are large blocks planted alone. 

 As a result of this situation, some experiments were con- 

 ducted during 1916-18 by Tufts ^ to determine the status 

 of the sterility (barrenness) of this variety in California and 

 to detennine the best poUinizers, if such are necessary. 



It was found that the Bartlett is to a limited degree self- 

 sterile under valley conditions, but entirely so in the foot- 

 * Tufts, H. P. Calif. Agr. Exp. Sta. BuU. 307. 1919. 



