68 Maine Agricultural Experiment Station. 1920. 



Self Fertility and Self Sterility in the Varieties of the Apple. 



— Concluded. 





Number 



sslfed 



Number fruit 



Number fruit n:>t 



Variety 







matured 



matured 



Winssap 2 



300 







300 



Winssap 13 



550 





2 



548 



White PiDpin 4 



100 





26 



74 



Whltnsv s Crab 4 



100 





4 



96 



Yeliow Transparent 2 



363 





2C 



343 



Yellow Transparent* 



25 





2 



23 



York ImDeria!* 



100 









York Imperial 3 



134 





1? 



133 



Even a cursory examination of this table will show that 

 the degree of self fertility in the apple is quite generally insig- 

 nificant. Within this group of one hundred and nineteen varie- 

 ties only 42 or less than half are known to have self-fertilized 

 and set fruit. Of these 42 varieties only 15 set fruit in any 

 numbers, the rest had only one or two fruit which matured rep- 

 resenting something less than five per cent of the total number 

 of crosses made. 



Table 2 shows one of the best commercial varieties, the 

 Baldwin to be self fertile in Maine and elsewhere. Of the other 

 leading commercial varieties Rhode Island Greening, Golden 

 Russett, Tolman Sweet, Twenty Ounce, Mcintosh and Graven- 

 stein proved to be self sterile in all tests. The varieties North- 

 ern Spy, Esopus Spitzenburg, Ben Davis, Fameuse and Olden- 

 burg proved very slightly fertile. Of the other commercial 

 varieties which proved somewhat more fertile might be men- 

 tioned the Jonathan, Early Harvest and Yellow Transparent. 



Considerable difference is evidenced by the record of the 

 set of fruit of a variety within the different states. The Bald- 

 win sets a very limited number of fruit in Vermont whereas in 

 Maine and Oregon its set of fruit was more numerous. The 

 Ben Davis in Maine and Vermont set no fruit whereas in 

 Arkansas and Oregon it set a limited number of apples. The 

 Red Astrachan proved self sterile in Maine and Vermont 

 but with a test made in Maryland set fruit on self fertilization. 

 These results make it seem probable that the environmental 

 conditions of the different states affect the self fertility of these 

 differently. Caution is consequently necessary in applying the 

 results of one state to that of another. 



