430 Report of the Department of Horticulture of the 



frustrated on the start, as the Dwarf Aristocrat was planted too 

 late to be used for the fertilization of the Livingston Stone and 

 the Hedrick blossoms. Pollen of the standards, however, was 

 secured for the fertilization of the Dwarf Aristocrat blossoms. 

 This one-sided cross was probably just as satisfactory as if recip- 

 rocal crosses had been made; for, first, the chances are that no 

 differences in the reciprocal crosses would have been found ; and, 

 second, the use of the dwarfs as female parents gave a check on 

 the crossing. Since the standard condition is always dominant to 

 the dwarf condition, the occurrence of a dwarf in the Fi genera- 

 tion, under these circumstances, would indicate that the cross had 

 not been made. No similar test could have been applied to the 

 reciprocal cross, since standard condition might in this case have 

 arisen either from continuance of the pure standard line or from 

 dominance of the standard condition in the cross. 



The self-fertilizing of varieties in the experiment was per- 

 formed by covering the flower clusters with paper bags while the 

 blossoms were in the bud stage, and later, when the pollen was 

 ready for shedding, jarring every other day until the blooming 

 was completed. 



The crossing of the varieties was more difficult than the self- 

 fertilizing and required more care. For the prevention of acci- 

 dental crossing, the flower clusters were covered while in bud. 

 One or two days before the pollen had matured, the stamens were 

 removed with the aid of a pair of forceps or some other instru- 

 ment; and two or three days later or whenever the pistils were 

 receptive, the stigmas were covered with the pollen of the desired 

 parent. Premature pollination always gave a very poor setting 

 of fruit.* As the blossoms in clusters mature at different times, 

 it was necessary to perform the emasculating and pollinating every 

 two or three days until the work was completed. In crossing it 

 should be remembered that the length of time for blossoms to 

 mature depends upon the temperature and that better results are 

 obtained when the pollen sheds freely, that is, on the bright, warm, 

 sunny days. 



•This fact is substantiated by Hartley, (See Bibliography 15.) 



