272 Missouri Agr. Exp. Sta. Research Bulletin No. 8 



It will be seen that especially the Chinese Cling group of peaches 

 and the green twig varieties have a long rest period and can not be 

 readily pushed into growth by warm periods earlier than about 

 January 20th, while such varieties as Crawford's Early, Foster and 

 all of the Heath Cling varieties could be much more readily pushed 

 into growth in the early season. Fitzgerald and Early Bernard are 

 not included in these experiments, but experience with them proves 

 that they have as short a rest period as Crawford's Early, and are 

 equally tender under Missouri conditions. Elberta, a Chinese 

 Cling seedling, the other parent of which is thought to be Crawford 's 

 Early, has a short rest period like Crawford's Early, while Carman 

 resembles the Chinese Cling in bud habits. Since the publication 

 of Bulletin No. 74, there has been opportunity to observe the pushing 

 during late February on Carman as compared with Elberta in south- 

 ern Missouri, and uniformly the Elberta pushes much more rapidly 

 during January and February, and even March, than Carman, and 

 on nearly every year it blooms earlier, though in North Missouri 

 where peaches bloom later and the effect of the rest period will thus 

 be entirely eliminated before blooming time, Carman and Elberta 

 are likely to bloom together. 



EFFECT OF VIGOR OF THE TREES ON THE REST PERIOD. 



It was found as published in Bulletin No. 74, Missouri Experi- 

 ment Station that prolonging the growth of peach trees in the fall 

 will prolong the rest period so that the fruit buds are not so liable 

 to be killed by cold periods following warm periods. This prolong- 

 ing the growth in the fall was generally accomplished by pruning the 

 trees severely, in this case two years before those tests were made. 

 This caused them to grow more vigorously throughout the summer 

 and to continue growth later and to hold their leaves late in autumn. 

 While the more vigorous growth continued through the second sum- 

 mer after the pruning, the additional vigor over the unpruned trees 

 was not so great. 



To test the effect of this additional vigor on the rest period, 

 twigs gathered on various dates from November 23 to January 13 

 were forced from two to three weeks in the greenhouse. Following 

 is a summary of the table published in Missouri Experiment Sta- 

 tion Bulletin No. 74, giving the result of these tests made during 

 the season of 1906-07. The vigorous, pruned trees are termed "cut 

 back" trees. 



