DORMANCY OF GLADIOLUS CORMS VI. EFFECTS OF TEMPERATURE TREATMENT ON BREAKING DORMANCY OF GLADIOLUS CORMS STORED IN A STORAGE ROOM AND OF THOSE GROWN UNDER DIFFERENT DAY-LENGTH

A high temperature treatment at 35° for 5 days followed by a low temperature treatment at 0-5° for 25 days was given at fifteen-day intervals to five groups each of two varieties (White Gold and Cardinal Prince) stored in a storage room from September 27 to November 26. The temperature treatment was apparently effective for sprouting of corms of both varieties at earlier period, but rather inhibitory at later period of dormancy. The plants of two varieties (Early Red and Spot Light) grown under short day-length (9 hr) showed slightly earlier flowering and corm-forming than those grown under natural long day-length. These plants were harvested from July 1 to Septmber 1 at twentyday intervals, and sprouting of their corms with and without temperature treatment similar to the previous method was investigated. Spot Light corms did not sprout irrespective of temperature treatment. Early Red corms always sprouted earlier in the temperature-treated lots, whereas they sprouted a little later in the non-treated lots. The temperature treated corms grown under the short day-length showed delaying and low percentage of sprouting. On the contrary, in the non-treated lots, sprouting of corms grown under the long day-length was slower than those grown under the short day-length.