UBC Theses and Dissertations
Some studies on the incidence of blothy ripening in greenhouse tomatoes in British Columbia Matsumoto, Tsutomu
Blotchy ripening (BR) of tomatoes is an irregular ripening of tomato fruits. This world-wide disorder has been a problem of the spring crop, particularly during the later part of May, in greenhouse tomatoes in British Columbia. For the investigation of the factors which affect the occurrence of BR in B.C., the following were considered: Correlation between the hours of bright sunshine and the incidence of BR, the influence of weekly alternation of light and temperature conditions on the incidence of BR, and the association of the incidence of BR and virus diseases. Examination of weather records led to a hypothesis which was tested in growth chambers. The light regimes employed consisted of a high and a low light condition. Concurrently two temperature regimes were used, one with a high maximum-temperature and the other with a low maximum temperature. Both regimes employed the same minimum temperature. The results of the studies were as follows: The cyclic occurrence of sunny weeks and cloudy weeks was associated with the incidence of BR in the B.C. greenhouse tomatoes. The weekly alternation of the light conditions produced 37% BR fruits when the plants were subjected to a constant day- night temperature cycle, but only 11% BR fruits, which was not significantly different from 6% BR in the control, was produced when the temperature conditions were alternated simultaneously and directly with light regimes. The role of tobacco mosaic virus (TMV) on the Incidence of BR in the B.C. greenhouse tomatoes did not appear to be important. The effect of potato virus (PVX) on the incidence of BR was not clear.
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