The Eleventh Regional Wheat Workshop For Eastern ... - Cimmyt

SOURCES OF VARIATION FOR GRAIN YIELD PERFORMANCE
OF BREAD WHEAT IN NORTHWESTERN ETHIOPIA
Tadesse Dessalegnl, Bedada Ginna 2 , T.S. Payne 3 , C.S. van Deventer 4 and
M.T. Labuschagne 4
IAdet Research Center, P.O. Box 8, Bahir Dar, Ethiopia
2Kulumsa Research Center (EARO), P.O. Box 489, Kulumsa, Ethiopia
3CIMMYT, P.O. Box 5689, Addis Ababa, Ethiopia
4Plant Breeding Department, UOFS, P.O. Box 339, Bloemfontein 9300, South Africa
ABSTRACT
Precise genotypic yield estimates from data of regional variety trials will
increase the probability of successful selection. Additive main effects and
multiplicative interaction (AMMI) analysis helps to understand sources of
variation, to interpret the genotype by environment (GE) interaction, and to
improve the probability of successful selection. A regional variety trial
conducted in 12 environments was subjected to AMMI analysis to reveal the
sources of grain yield variations and interaction. Environment and genotypes
were highly significant but their interaction was non-significant. The
environment sum of squares (SS) dominated the analysis even though the
interaction SS was larger than genotypic SS. AMMI partitioned the interaction
SS into six Interaction Principal Component Axes (IPCAs) with two of them
significant; the AMMI biplot described different patterns of interactions. The
contribution of environment was 86.4%, indicating differences in
environments (i.e., genotype yields ranged from 6205 kglha at Adet to 1643
kg/ha at Injibara, as lnjibara is the lowest potential area for wheat production).
Genotypes contributed 5.7% of the variation and the difference between them
was significant. Genotypes such as HAR1868, HAR18.65 and HAR2096 were
consistently high yielding varieties across environments with mean yields of
4105, 3932 and 3786 kglha, respectively. They had positive interaction with
high yielding locations (Adet, Motta, Fenoteselam and Dabat) indicating their
adaptation to these locations. The above locations showed consistency of main
effects and interactions across years (i.e., the environments were suitable to
discriminate this set of genotypes). Therefore, the result indicated consistency
of ranking of genotypes (i.e., the top yielding in the top four ranks in both
AMMI predicted and observed yields) that facilitates the use of mean yields as
a selection criterion for variety recommendations. As a result, HAR1868
(Shina) was recommended for production in 1998 and HAR2096 was verified
for release in 1999.
INTRODUCTION
Bread wheat (Triticum aestivum L.) is a major crop in Northwestern Ethiopia. Fanners
demand to grow high yielding semi-dwarf bread wheat cultivars, because of better grain yield
potential than many traditional crops. Wheat grows in a wide range of areas in the region
differing in altitude, soil type, temperature, rain fall distribution, and the grain yield potential
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