Fjölrit RALA - 15.12.2000, Blaðsíða 18

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Development of Engmo. As dates for onset of growth, green plots, heading and anthesis were
not estimated uniformly at the four locations, some differences in the estimates can exist
between the countries. In order to get a better coordinated estimate of development, samples
of Engmo were collected on each harvest date at all locations and the developmental stage
was subsequently evaluated by the same person. Twenty plants were observed from each
harvest date and location. The developmental stages, reached by the most mature plants in
each sampling, are listed in Table 12 (see footnote, Table 12). However, if only one or two
plants were at the highest developmental stage, the sample was classed at the next stage
below.
These results agree with the relatively early heading date for timothy in Upernaviarsuk
in 1996 and the late heading date in Kollafjorður reported in Tables 9 and 10. This is also true
for other pattems found in Tables 8-11 for 1997. That year the heading date was relatively
late in Upemaviarsuk but early in Narsarsuaq, as in 1996.
Table 12. Developmental stages of Engmo at different harvest times and locations 1996 and 1997. Numbers in
parentheses indicate harvest dates.
Harvest number
1996 1 2 3 4 5
Faroe Islands 21 (29.5.) 22 (12.6.) 31 (26.6) 45(10.7.) 58(1.8.)
lceland 22 (4.6.) 31 (18.6) 50 (2.7.) 56(16.7.) 58(30.7.)
Narsarsuaq 22 (9.6.) 54 (24.6.) 58(8.7.) 58 (22.7.) 60 (9.8.)
Upemaviarsuk 22(10.6.) 50(23.6.) 54(10.7.) 58(21.7.) 60 (22.8.)
1997
Faroe Islands 22 (2.6.) 31 (16.6.) 45 (30.6.) 56(14.7.) 58 (30.7.)
Iceland 22 (27.5.) 22(10.6.) 45 (24.6.) 52 (8.7.) 56 (22.7.)
Narsarsuaq 21 (11.6.) 52 (26.6.) 58 (9.7.) 58 (23.7.) 60 (7.8.)
Upemaviarsuk 22 (13.6.) 32 (28.6.) 50(11.7.) 54 (25.7.) 58(11.8.)
Code description: 21 = 1 developed leaf, 22 = 2 developed leaves, 31= 1 node developed, 32 =2 nods
developed, 45 = boots swollen, the ear palpable but not visible, 50 = less than half of the ear visible, 52 = more
than half of the ear visible, 54 = ear bearing intemode visible, 56 = ear bearing intemode visible to at least the
length of the ear, 58 = ear bearing intemode visible to at least twice the length of the ear, 60 = first anthers
appear (after Simon and Park, 1983; Thorvaldsson, 1988).
Temperature and development. The temperature during the growth period was similar at
three of the four locations. In Upemaviarsuk on the other hand, the average temperature for
the spring months May-June was 2-3 °C lower. Nevertheless the date of heading of timothy
was comparable to other locations in 1996 and not much delayed compared to the other
locations in 1997. On the other hand, anthesis was about two weeks later in Upemaviarsuk
(27.8.) than at the other locations (6.8.). Approximately the same temperature sum was
needed from heading to anthesis of timothy in Greenland (both locations) and Iceland, 450
day degrees (days by mean temperature x days). In Kollafjorður only 350 day degrees were
required for the same process. How heading and anthesis were estimated varied somewhat
with the locations, and this may partly explain the difference. However, it seems that not as a
high temperature is needed in Kollafjorður.