540 



Quality in Potatoes. 



[dec, 



cause the cellular structure to be broken down, and a degree of 

 mealiness is the result. 



The structural character of the tubers is influenced by 

 the conditions of the soil and climate in which the potatoes 

 grow. As a result of these investigations, it is believed that the 

 quality of mealiness in a potato when boiled, and to a con- 

 siderable extent the flavour, is influenced in the main by the 

 following considerations: (1) the daily range of soil and atmos- 

 pheric temperature during the growing period ; (2) the degree 

 of ripeness of the tuber when the plant dies ; and (3) the 

 physical condition and type of the soil. 



In 1903 it was ascertained by careful examination that tubers 

 growing at different depths varied in cooking quality, and that 

 the structural characteristics varied with the depth. In 1904 

 potatoes were planted on experimental plots at depths of two, 

 four, and six inches. The temperature and moisture of the soil 

 at the different depths were recorded, and at shallow depths the 

 variations in both were found to be considerable. The differ- 

 ence between the mean temperature at different depths over 

 twenty-four hours was small, but it was observed that a curve 

 of the temperature at intervals of two hours showed that the 

 temperature at two inches runs considerably higher and lower 

 than at the other depths. This wide variation of the hourly 

 temperatures and comparatively uniform temperatures for the 

 twenty-four hours between the different depths points to the 

 conclusion that the quality of the tuber is not so much affected 

 by the sum total of the temperature units, within reasonable 

 limits, as it is by the hourly variations of temperature during 

 the growing season. 



In the same way the percentage of moisture was found to 

 vary more at the depth of two inches, and, as might be ex- 

 pected, was much lower than in the deeper layers, the averages 

 for the season being 13*27 at two inches, 15*12 at four inches, 

 15*91 at six inches, and 15*69 at eight inches. 



What are precisely the best conditions will form the subject 

 of further investigations, but the results obtained up to the 

 present point admit of the following suggestions being made : — 



1. Tubers grow out upon a short stem or stalk from the 

 plant stem at regular nodes above the planted tuber. It is 



