804 



Journal of Agricultural Research 



Vol. XX, No. ix 



Table V. — Rate of sweetcorn ripening during the month of August, calculated from 



Baltimore temperatures 



Stevens and Higgins state that the corn-picking season in Maryland 

 has a much higher average temperature than the corresponding season 

 in Maine, the difference being sufficient to cause considerably greater 

 deterioration in picked corn during a given period. 1 They also derived 

 the exponential and physiological indices corresponding to the daily 

 normal temperatures for the corn-canning seasons of both localities. 

 The means of these two sets of indices were both greater for Baltimore, 

 Md., than for Portland, Me.; but they were unable to decide which 

 method furnishes the best criteria of the relative rates of deterioration of 

 picked corn in the two localities. The data presented in this paper and 

 in a previous paper by Appleman and Arthur 2 lend support to the 

 exponential indices as a good measure of the relative climatic tem- 

 perature efficiency for the deterioration of picked corn in different 

 localities. 



The quality of canned corn may be influenced not only by the tem- 

 perature at which the corn is handled but also by the effect of tempera- 

 ture on the rate of ripening. A slow rate of ripening gives a greater 

 range in the number of days that the corn may be picked in good con- 

 dition. Corn that ripens in very warm seasons, for example in the 

 month of August in Maryland, requires very close attention lest the best 

 stage for picking be allowed to pass. The data presented in this paper 

 should furnish a more rational basis for picking green sweetcorn. 



SUMMARY 



Sweetcorn is considered ripe when the growth of the kernels ceases 

 and the chemical changes in the corn have nearly attained equilibrium 

 positions. The maturing of corn consists essentially in the loss of water. 



The chief changes in percentage composition of corn during ripening 

 consists in the depletion of sugars and the increase of starch. 



In the very early stages of ripening the reducing sugars predominate; 

 therefore the stage of highest total sugar content does not necessarily 

 coincide with the stage of greatest sweetness. 



1 Stevens, Neil E., and Higgins, C H. op. cit. 



2 Appleman, Charles O., and Arthur, John M. op. cit. 



