Teff Reaserch and Development - Official web site of Etteff

Floral biology and crossing of tef 75
plants showed slight sigh of chlorosis, being slightly yellowish-green instead of their
Normal healthy green. The other abnormality produced by 3 days in the dark was the
accumulation of open florets, not only per panicle but also per Spikelet, as there were
more than 90 flowers open on a single panicle 26 centimeters long with in mane cases,
two cases, two florets open on a Spikelet.
The 96 hours dark treatement induced a similar level of male sterility (2.3% and total
sterility (4%), to 72 hours darkness. All the mature florets were already open when taken
out of darkness and in the normal ones the anthers dehisced after 26 minutes. The plants
showed a marked loss of chlorophyll. After 120 hours of darkness many flowers were
totally sterile (16%) but there was not a proportional rise in the number of male sterile
flowers. Further disadvantage was that the plants were becoming weak; they showed a
marked degree of chlorosis and requiring support to keep the culm upright . the normal
anthers took a long time before dehiscing. (30 minutes) and there was a high number of
open flowers per panicle and per Spikelet. The 144 hours of dark treatement induced the
highest percentage of male sterility (8%), but also the highest percentage of totally sterile
florets (26%) . although it induced the highest proportion of male-sterility it cannot be
utilized for breeding purposes because the plants suffered greatly from chlorosis. There
were high number of florets open per panicle, and spikelets, and in the normal florets
anthers took 30 minutes to shed their pollen. All mature florets were already open when
taken out of darkness.
Table 2. Effect of dark treatement on flowering in tef.
Duration of no. of normal male sterile wholly sterile average no.
Treatment (hr) flower (300 observed) flower pollen after floweing of flours open
Control
24
48
72
96
120
144
300
300
300
275
280
244
196
0
0
0
6
7
9
24
No % No. % (minutes) per panicle
The usefulness of dark-treatment to control flowering was studied in a separate experiment. It was found
that when plants are kept in the dark in a room where the temperature fluctuated between 14-28 o c,
darkness prevents flower opeining only up to 30 hours. After that time they started to open their florets,
and some florets managed to dehisce their anthers 8-10 hours later while still in the dark, that is, after 38
to 40 hours of continuo dark-treatment. This shown that darkness separates or prologs the time gap
between the processes of flower opening and anther dehiscence markedly. In the presence of light,
another dehiscence follows within 25 minutes of the first sign of flower opeining; under darkness it
takes place 8-10 hours later. This is true for the florets that will open within the first 48 hours and after
48 hours, although the plant manages to continue flowering, most of the anthers are prevented from
dehiscing. Darkness also affects flower closure, since once open it keeps them that way for more than 48
hours while normally in the presence of light all would be closed in about 2 hours. This explains why the
number of florets open, but with unrevised anthers, rises for all the plants that received more than 48
hours dark treatement. Even when returned to the light, the florets on plants kept for 48 hours in the
more than 5 hours to close, and the ones that were dark treated for more than 48 hours took more than 8
hours to close.
0
0
0
2
3
8
0
0
0
8
13
47
79
14
17
17
24
26
30
30
45
50
70
100
180
220
250