PEAR GROWING IN CALIFORNIA. 233 



There is little definite information on this point, although we do 

 know that the influence of pollinizers varies inversely with the dis- 

 tance. In order to secure efficient pollination with the fewest 

 possible pollinizers, I would recommend 1 to 7 or 8 and would place 

 the pollinizers as every third tree in every third row, in such a 

 way that the spaces in the pollination rows are broken, thus : 



In substantiation of Mr. Tufts' conclusions, the writer knows of 

 one large pear orchard which has growing in it a few Winter Nelis 

 trees. The owner of the orchard has pointed out to me the load of fruit 

 on surrounding Bartletts, which is considerably heavier than in other 

 parts of the orchard. Every year it is said these Bartletts are the 

 heaviest producers in the orchard. One exceedingly interesting case of 

 increased productivity of the Bartlett through cross-pollination is found 

 in the experience of Mr. A. L. Wisker at Grass Valley. In experiment- 

 ing with many different varieties of pears, Mr. Wisker had occasion 

 to graft over a portion of a block of old trees containing only Bartletts, 

 to a miscellaneous lot of other varieties. In 1913, according to Mr. 

 Wisker 's statement, 31 of the Bartlett trees that were left in the block 

 bore 13 boxes of marketable pears. With eight other varieties in bloom 

 during the season of 1914, 26 boxes were produced. In 1915, with over 

 fifty varieties blooming, the production of these same 31 trees was 

 78 boxes of marketable pears and 30 boxes of culls, the latter because 

 of blister mite attack. As the trees are over fifteen years of age the 

 difference in the amount of fruit produced during the three successive 

 seasons could not be attributed to the increase in age, and can only be 

 accounted for by the beneficial effect of the pollen from the other varie- 

 ties which were introduced into the orchard by grafting. 



*Bulk of planting. 

 "Pollinizer. 



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