Mar. 1,1931 Temperature Efficiency for Ripening of Sweetcorn 805 



Calculated as percentages of dry weight, the changes in fat, crude 

 fiber, and total nitrogen occur during the very early stages of ripening. 

 For the remainder of the ripening period these percentages remain 

 fairly constant. 



The rate of starch synthesis in the kernels seems to be the controlling 

 factor for several supplementary processes. The rate at which the ratio 

 of total sugar to starch decreases is a good measure of the ripening rate 

 and was employed for that purpose. 



Temperature is the controlling factor for the rate of ripening in sweet- 

 corn. Several temperature indices were employed to evaluate climatic 

 temperature efficiency for the ripening processes. The exponential 

 indices were found to furnish the best criteria of the temperature effi- 

 ciency for sweetcorn ripening. 



A late crop of corn required 15 days for the same period of ripening 

 that required only 6 days for an early crop, a time ratio of 2.5. The 

 averages of the daily exponential indices for the two seasons were prac- 

 tically in the same ratio. Therefore, the rate of ripening in sweetcorn, 

 within a wide range of temperature, appears to adhere rather strictly 

 to the Van't Hoff-Arrhenius principle. 



The rate of ripening being inversely proportional to the exponential 

 indices, a basis was furnished for an approximate prediction of the 

 number of days required in different localities and at different seasons 

 in the same locality for corn to pass from the beginning of kernel forma- 

 tion to the best edible stage, as well as the maximum number of days 

 that the corn may be expected to remain in this condition. 



