398 POLLINATION AND FRUIT SETTING 



(6) Pears, Many Varieties of Pears Set Better Crops if 

 Pollinated with Other Varieties. In the Eastern sections of the 

 United States, experiments and field observations indicate that 

 the following varieties are either entirely self-unfruitful, or 

 they are self-unfruitful to such a degree that satisfactory crops 

 will not be produced unless they are pollinated with other 

 varieties : 



Anjou Columbia Mount Vernon 



Boussock Easter Beurre Sheldon 



Clairgeau Howell Superfin 



Clapp's Favorite Lawrence Winter Nelis 



Kieffer 



In addition to the above varieties, the following varieties 

 will set much better crops if cross-pollinated, although fair 

 crops are occasionally produced with their own pollen: 



Bartlett Gorham 



Buerre Bosc Phelps 



Cayuga Souvenir du Congress 



Ewart 



The following varieties set fair crops with their own pollen 

 but no doubt would be benefited by cross-pollination: 



Buffum Manning 

 Duchess d'Angouleme Seckel 

 Flemish Beauty Tyson 

 LeConte 



So far as is known, practically all varieties of pears which 

 bloom at the same time will cross successfully with each other. 



(c) Plums, By far the largest percentage of Japanese 

 plums {Prunus salicina) studied in this country are self- 

 unfruitful and thus should not be planted in solid blocks. The 

 following varieties are included in this list: 



Abundance El Dorado Ogon 



Apex Engre Prize 



Burbank Formosa Satsuma 



Chabot Gaviota Sultan 



Combination Kelsey Upright 



Duarte Kerr Wickson 



Mam 



