Killing of Plant Tissue by Low Temperatueie 



277 



can the date of blooming often be appreciably affected as far north 

 as Central Missouri. In southern Missouri, on account of the pro- 

 tection from early autumn frosts rendered by the excellent air drain- 

 age and on account of its being further south, the trees grow later in 

 autumn and for the same reasons, blooming is likely to occur from a 

 week to occasionally six or seven weeks earlier than in central Mis- 

 souri. Thus the season there between the beginning of dormancy 

 and blooming time is often short enough that the influence of the 

 rest period may be observed even at blooming time. Trees of varie- 

 ties with a long rest period or trees that grow late in autumn will 

 bloom later, as in the case of the pruned and fertilized trees mentioned 

 above. 



Relation of Thinning the Fruit to Hardiness. Another phase 

 of orchard practice with which it seems it would be possible to in- 

 fluence the rest period, is thinning the fruit. In tests reported in 

 Bulletin No. 74 of the Missouri Experiment Station where trees had 

 one-half of the fruit thinned and the other half left to bear a full crop, 

 out of five trees so treated in each case during the following winter 

 a larger percentage of buds were killed on the side that was not 

 thinned than on the side that was thinned, and where the thinning 

 was very heavy or where all of the fruit was taken off, the difference 

 was very marked. The following table gives the results: 



Table 44. Showing Effect of Thinning on Hardiness, Buds 



Started Into Growth by Warm Period 



Before End of Rest Period. 



Variety 



Treatment 



Seedling ! Fruit thinned .... 



Seedling F"ruit not thinned . 



Elberta Seedling. 

 Elberta Seedling.. 

 Oldmixon Cling... 

 Oldmixon Cling... 

 Poole's Favorite. 

 Poole's Favorite. 

 Poole's Favorite. 

 Poole's Favorite. 



Fruit thinned 

 Fruit not thinned . 



Fruit thinned 



Fruit not thinned. 

 Fruit thinned. . . . 

 Fruit not thinned . 

 Fruit thinned .... 

 Fruit not thinned 



Average (thinned) .... 

 Average (not thinned), 



