Studies on cold injury of citrus sinensis cultivar fukuhara orange fruit 1. relationship between flesh freezing and the subsequent development of dry juice sacs
Uchida, M.
Bulletin of the Fruit Tree Research Station Series D (Kuchinotsu) (5): 59-66
1983
Accession: 006505741
Six year old potted trees were incubated in cold environment. The occurrence of dry juice sacs was estimated (R2 = 0.65) by a multiple regression equation using the lowest temperature and the freezing period of fruit. This occurrence of dry juice sacs was directly related to the extent of freezing. The degree of development of dry juice sacs was determined by the following equation: Y = -0.599 X1 + 0.0063 X2-3.43 (.sigma. = 0.48). In the equation, Y,X1, and X2 are the degrees of development of dry juice sacs, the lowest temperature (centigrade) and the continuous period (minutes) in the lowest temperature environment, respectively. When this equation was applied for estimation of dry juice sac occurrence using the temperature data observed at a fruit tree research station, the estimated values were similar to those obtained by field observations. Some modification of the temperature (such as the value of 1.degree. C higher than the lowest temperature, X1, and the continuous period below the modified lowest temperature, X2) was required for estimating values approximately equal to those observed in the field.