| Abstrakt: |
Seed samples of 12 wheat varieties grown in 1960 and 1961 were tested for post‐harvest dormancy under several temperature regimens at harvest time and at intervals for 80 days after harvest. Seed harvested in 1960 was tested both years. Speed and completeness of germination was expressed as a Promptness Index (PI). PI was not significantly below that of the control in any variety at 10 C germination temperature. At 20 C, all 12 varieties were dormant at harvest and this dormancy persisted from 20 to 60 days, depending upon variety. At 30 C, all 12 varieties displayed a deep, persistent dormancy from which only ‘Burt’ nearly recovered after 80 days. Testing of l‐year‐old seed revealed that, of the 12 varieties, only ‘Federation,’ ‘Columbia,’ and Butt had lost all 30 C sensitivity 1 year after harvest. A diurnal regimen of 5 C for 8 hours and 30 C for 16 hours displayed a small but persistent reduction in PI which was still present in several varieties 75 days after harvest. In nondormant seed, PI appears directly related to germination temperature; in dormant samples, the relationship is inverse. |
Plný text