Table II.
Responses of barley plants grown for 19 d under 12 h photoperiods to 10 min of EOD R, FR, R followed by FR (R/FR), or FR followed by R (FR/R) light
Treatment | Floral Stage
|
Apex
Length
|
No. of Tillers
|
Dry Wt
|
||||
---|---|---|---|---|---|---|---|---|
BMDR-1 | BMDR-8 | BMDR-1 | BMDR-8 | BMDR-1 | BMDR-8 | BMDR-1 | BMDR-8 | |
mm | g | |||||||
Control | 3.9 ± 0.5a | 2.0 ± 0.0b | 12.9 ± 3.5a | 1.8 ± 0.1b | 1.3 ± 0.1a | 1.3 ± 0.1a | 0.175a | 0.167a |
R | 3.8 ± 0.4a | 1.9 ± 0.1b | 13.6 ± 2.5a | 1.5 ± 0.1b | 0.9 ± 0.1a | 1.0 ± 0.1a | 0.134a | 0.149a |
FR | 4.1 ± 0.4a | 2.0 ± 0.0b | 11.1 ± 2.1a | 1.7 ± 0.1b | 0.4 ± 0.1b | 0.4 ± 0.1b | 0.166a | 0.134a |
R/FR | 4.0 ± 0.5a | 2.0 ± 0.1b | 8.1 ± 1.9a | 1.6 ± 0.1b | 0.2 ± 0.1b | 0.4 ± 0.1b | 0.146a | 0.150a |
FR/R | 3.6 ± 0.5a | 2.0 ± 0.1b | 9.5 ± 2.5a | 1.6 ± 0.1b | 0.9 ± 0.1a | 0.7 ± 0.1ab | 0.166a | 0.153a |
Seeds were sown in plastic trays and subirrigated with full-strength Hoagland solution. All seeds were placed in a growth chamber in DD at 20°C ± 0.1°C for 4 d prior to transfer to a growth chamber set to 12 h of CW and 12 h of dark. At the end of each photoperiod plants were given a 10-min pulse of R, FR, R followed immediately by FR, or FR followed immediately by R. Following treatment for 18 d, the average fresh weight of the shoots was determined, and 10 plants that were within ±10% of the mean fresh weight were selected. These were then dissected under a dissecting microscope to determine the stage of floral development, the length of the inflorescence, and the number of tillers formed. Significance was established by analysis of variance. Different letters indicate a significant difference at P = 0.05.