Yield stability of timothy varieties in the Swedish VCU-testing

Yield stability of timothy varieties
in the Swedish VCU-testing
Magnus A. Halling
SLU Sweden, Crop Production Ecology
NJF Seminar 384 10–12 August 2006
Akureyri, Iceland

Aim and questions
• Are there any differences in yield
stability between Swedish-bred and
foreign-bred timothy varieties under
Swedish conditions
• The origin of timothy (Phleum
pratense L.) varieties tested in
Sweden has expanded during the
last ten years
2
Illustration: Langer & Hill 1991
Swedish University of Agricultural Sciences
Department of Crop Production Ecology
www.slu.se, www.vpe.slu.se

Materials and methods
• Data from the Swedish VCU
testing of timothy during the
period from 1996 to 2005
• Ten sites between latitude N
60°17' and N 55°32'
• Two harvesting years and
two harvests per year
3
Swedish University of Agricultural Sciences
Department of Crop Production Ecology
www.slu.se, www.vpe.slu.se

Materials and methods, cont.
• Ten varieties selected
– four from Sweden (Alexander [65], Carola [18],
Jarl [24] and SW TT2528 [12])
– one from Norway (Noreng [10])
– one from Finland (Tuukka [6])
– one from Denmark (Tundra [9])
– one from Germany (Liglory [31])
– one from Canada (Glacier [11])
– (Numbers in brackets are the number of trials
for each variety)
4
Swedish University of Agricultural Sciences
Department of Crop Production Ecology
www.slu.se, www.vpe.slu.se

Phenotypic stability - equation
Y ij
= m + B i
E j
+ d ij
+ e ij
Y ij
= performance of the i-th variety in the j-th
environment
m = general mean
B i
= regression coefficient of the i-th variety
E j
= environmental contribution of the j-th
environment obtained by the mean of each
environment
d ij
= the regression deviation of the i-th variety in
the j-th environment
e ij
= effect of the mean experimental error
5
Swedish University of Agricultural Sciences
Department of Crop Production Ecology
www.slu.se, www.vpe.slu.se

Phenotypic stability-interpretation
• Values of B are used as a relative
measure of the sensitivity of the
varieties to changes in environmental
stress.
– B equal to 1.00 = average sensitivity
– B greater than 1.00 = greater sensitivity than
average
– B less than 1.00 = less sensitivity than average
6
Swedish University of Agricultural Sciences
Department of Crop Production Ecology
www.slu.se, www.vpe.slu.se

Results
• Overall significant differences
between B-values in all harvests,
except second harvest in ley year 1
• Few significant differences in
phenotypic stability between
Alexander (check) and other timothy
varieties, even though they have a
broad geographic origin.
7
Swedish University of Agricultural Sciences
Department of Crop Production Ecology
www.slu.se, www.vpe.slu.se

Results, cont.
• Carola being the most unstable (B =
1.14) and Noreng being the most
stable (B = 0.76) in the first harvest
in the second ley year
• Interestingly, they had the same
average dry matter yield in this
harvest
8
Swedish University of Agricultural Sciences
Department of Crop Production Ecology
www.slu.se, www.vpe.slu.se

9 000
Noreng vs Carola first
harvest 2nd year
9 000
8 000
8 000
Variety mean kg DM ha-1
7 000
6 000
5 000
Variety mean kg DM ha-1
7 000
6 000
5 000
4 000
4 000
3 000
3 000 4 000 5 000 6 000 7 000 8 000 9 000
Site mean kg DM ha-1
Noreng
3 000
3 000 4 000 5 000 6 000 7 000 8 000 9 000
Site mean kg DM ha-1
Carola
9
Swedish University of Agricultural Sciences
Department of Crop Production Ecology
www.slu.se, www.vpe.slu.se

Concluding remarks
• Few significant differences in phenotypic
stability between Alexander and the
timothy varieties were detected
• Phenotypic stability and DM yield can give
different information of varieties
• Should phenotypic stability be introduced
in the evaluation of the variety testing
• In breeding, the use of phenotypic stability
has reported to be valuable (Helgadóttir &
Kristjánsdóttir, 1991)
10
Illustration: Langer & Hill 1991
Swedish University of Agricultural Sciences
Department of Crop Production Ecology
www.slu.se, www.vpe.slu.se

Thank you for your attention
11
Swedish University of Agricultural Sciences
Department of Crop Production Ecology
www.slu.se, www.vpe.slu.se