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



Table 49. Showing Percentage of Young Fruits From Which 



THE Calyx Tube Has Just Fallen Killed by a 



Temperature of 28 F. April 30, 1908 



It will be seen that large percentages of the fruits were killed 

 only on early varieties like Sneed and Alexander that had reached a 

 larger size. In the southern portion of Missouri where the fruit 

 was larger, more was killed than at Columbia, though the tempera- 

 ture was higher, Koshkonong reporting 32 F. Of course in the 

 lower land where most was killed, the temperature was naturally 

 lower. It is apparently certain then that under average seasonal 

 conditions, the older the fruit at the time of the freeze, the more 

 easily it kills. It is possible that this would not be true in years 

 when the bloom is pushed out very rapidly by exceptionally warm 

 weather and when continuous cool weather follows the setting of the 

 fruit. There is a rather general opinion that just when the calyx 

 tube falls, the fruit is left more susceptible to cold because it has lost 

 the insulation furnished by the calyx tube and requires time for ad- 

 justment. The fact that pistils of unopened flowers are not more 

 easily killed when the external flower parts are removed, and the fact 

 that buds of the peach were not more easily killed by freezing when 

 the scales were entirely removed, would indicate that with the slow 

 falling of the temperature that prevails under natural conditions, the 

 insulation amounts to but little. It seems certainly true, from the 

 experience of the season of 1908, that peach fruits are more tender a 

 week or more after the calyx falls than say one day after it falls. 



In examining, the fruits that were killed in the southern portion 

 of the State in that year, in very many cases no injury was found 

 to the flesh of the fruit, but the seeds were killed. Where the rate 

 of fall of temperature is not too rapid under laboratory conditions, 

 it is generally the seeds that are killed at the highest temperature. 

 In fact from a large number of observations upon the results of 



