Killing of Plant Tissue by Low Temperature 269 



ling, have been found hardy under the same conditiofis. Champion 

 is also above the average in hardiness under fully dormant conditions, 

 so far as observations in Missouri indicate. 



Of the more tender varieties when fully dormant Hedrick lists, 

 from the opinion of New York and Michigan growers, Crawford's 

 Early, Crawford's Late, Chairs Choice, Reeves' Favorite, and 

 Elberta. 



In Missouri these varieties are among the most tender on such 

 years under Missouri conditions, with other peaches of the same 

 type as Golden Gate running even more tender, and Oldmixon Free 

 and Cling and the Heath Cling group, and Fitzgerald and Early 

 Bernard, being slightly more hardy. 



Rest Period of Peach Fruit Buds. During some of the seasons 

 mentioned above, especially that of 1905-06, a large percentage of 

 the buds were killed at a high temperature because they had been 

 previously started into growth by warm weather. By referring 

 to the temperature chart it will be seen that on many years in Co- 

 lumbia, and on a large majority of years at Koshkonong in the extreme 

 southern part of Missouri, the temperature for December, January 

 and February will average as high as for those three months in Co- 

 lumbia in 1905-06. 



During the writer's observations there has very seldom been 

 a year when buds in the peach section of southern Missouri have 

 not been started sufficiently by February 1 to be killed by a tem- 

 perature considerably higher than would be required to kill buds 

 in northern Missouri, or certainly in Michigan, New York or New 

 England on the same date. 



VARIETIES WITH THE LONGEST REST PERIODS. 



Any one who has had experience with a large number of varieties 

 of peaches in a climate like that of southern Missouri has observed 

 that there is a wide difference between the amount of starting by Feb- 

 ruary 1 on different varieties. Thus it will be seen by referring to 

 Table 39 that a smaller percentage of buds were killed on February 

 5, 1906, by a temperature of -3 F., following a warm period, on Gen- 

 eral Lee, Chinese (ling and Sneed of the Chinese C^Iing group, and 

 the Green Twig varieties such as Snow and Ortiz, and on Lewis and 

 Early Michigan of the Hills Chili group, than were killed on varieties 

 like Crawford's Early, Elberta, Fitzgerald and the Heath Cling 

 varieties. 



