366 



FUNDAMENTALS OF FRUIT PRODUCTION 



Table 69. — Number of Heatings Necessary to Protect Utah Orchards 

 {After West and Edlefsen'^°'') 



peaches and 89 for the apples would make a considerable item in the 

 cost of production. In addition, the later blooming fruit is not only- 

 likely to encounter fewer frosts but such as it does encounter are likely 

 to be less severe. Finally, it should be recalled that the later stages of a 

 blossom's development are the most tender; for this reason also a given 

 frost is likely to damage the early variety more. This double effect is 

 well shown in Table 70. 



Table 70. — Percentage op Peach Blossoms Killed by Temperature of 28°F. 

 (After Garcia''^) 



Varieties 



Fruits just 

 setting 



Freshly opened 

 flowers 



Buds about to 

 open 



Elberta 



Crothers 



Salway 



Texas King .... 

 Hynes' Surprise 

 Alexander 



This table shows that for blossoms just setting fruit there was not 

 enough difference to indicate any varietal superiority in hardiness. How- 

 ever, Elberta, Crothers and Salway blossoms were all at the most ad- 

 vanced stage which is very tender. The three other varieties had a 

 considerable number of blossoms less advanced at the time of the freeze 

 so that, despite a rather large percentage of killing, the fruit of these 

 varieties had to be thinned, while the first three varieties bore very little, 

 Elberta in fact bearing none at all. 



Table 71is based on the Mikesell data,"^ with additions. Though computed 

 rather arbitrarily it shows in a general way the relative susceptibility to frost 



