638 



Journal of Agricultural Research 



Vol. XII. No. 10 



BAGGING TESTS 



The final test for the fertility of pollen is its behavior when used in 

 pollination. The simplest method of testing pollen fertility is to bag 

 the flowers before they open. This method has been used very exten- 

 sively by several investigators in self-sterility studies of the pear, apple, 

 cherry, peach, and grape and has been found to be efficient under favor- 

 able conditions. Observations by growers upon large blocks of any of 

 the hermaphroditic varieties of strawberries agree that strawberries are 

 all self-fertile, physiologically, wherever normal pollen is produced, so 

 that the question of self -sterility does not enter into the problem. 



Bagging tests were made on 106 varieties and 40 unnamed seedlings 

 produced at the Minnesota Fruit Breeding Station. The detailed results 

 and summary of these tests are given in Table X, and show (i) that in 

 the hermaphroditic varieties studied no physiological self -sterility exists; 

 (2) that wherever morphologically normal pollen is present fertilization 

 takes place; and (3) that the extent of fertilization is dependent upon 

 the percentage of normal pollen produced. 



Table X. — Degree of setting of the fruits of various positions on the inflorescence on g8 

 hermaphroditic varieties and jg seedlings of strawberries when bagged 



Variety. 



Primary. 



Secondary. 



Tertiary. 



Quaternary. 



Total. 



Abington 



Abundance 



Amanda 



Arizona 



Arojna 



Barryittore 



Bederwood 



Bradley 



Brandywine 



Brown Beauty. . . . 



Charles I 



Chesapeake 



Clara 



Climax 



Clyde 



Cooper 



Commonwealth 



Corsican 



Darlington 



Dorman 



Duncan 



Early Jersey Giant 



Early Ozark 



Ekey 



Enhance 



Ewell Early 



Excelsior 



First Quality 



Candy 



Gill 



Glen Mary 



Gold Dollar 



Good Luck 



Goree 



Grand Marie 



Hanbeck Beauty . . 

 Haverland "■ 



a Not certainly true to name. 



