308 



POMOLOGY 



Table LXXXVII 



effect of cross-pollination on the set of fruit 



(after alderman) 



Rome Beauty, not crossed . 



Rome Beauty, crossed 



York Imperial, not crossed 

 York Imperial, crossed . . . . 



Wagener, not crossed 



Wagener, crossed 



Here it will be seen that the set of fruit was materially 

 increased by crossing. The percentage of set was increased 

 with the Rome three and a half times, with the York four- 

 teen, and with the Wagener seven times. In addition, the 

 weight of the Rome was increased nearly 28 per cent and the 

 York 42.7 per cent over the size of the self-pollinated fruits. 



275. The pear. — Since many varieties of pears are self- 

 sterile and probably because of the influence of the work of 

 Waite,^ considerable attention has been given to a study of 

 this fruit. Bailey ^ says "Many of the varieties of pears are 

 infertile with themselves: they need the pollen of other va- 

 rieties to cause them to set fruit freely. Probably any va- 

 riety will fertilize any other variety in case the two bloom 

 simultaneously." Waite showed that out of thirty-six va- 

 rieties tested, twenty-two were self-sterile, but called partic- 

 ular attention to the sterility of the Kieffer. 



Fletcher ^ has shown that "unsatisfactory results may be 

 expected from planting either Bartlett or Kieffer in large 

 blocks, so that cross-pollination by insects is not general. 



' Loc. cit. 



2 Standard Cycl. Hort. V: 2506. 



3 Va. Agr. Exp. Sta. Ann. Rept. 1909-10. pp. 213-224. 



