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

Field response ofbread wheat genotypes to Septoria tritici blotch - Temesgen and Payne
Grain Yield Performance of Bread Wheat Genotypes
The analysis of variance for the individual locations and the combined analysis of variance
for grain yield are presented in Table 10. The combined analysis of variance for the mean
grain yield indicated that highly significant difference (P=O.O 1) were observed among the
genotypes. The main effect of the environment and the interactions were also significant. The
significance of G x E interaction indicated that the yield performance of the genotypes
differed between locations.
The magnitude of the interaction effect was low, as compared to the main effects of the
genotypes, indicating that some genotypes performed consistently across the locations.
Comparison of mean grain yield of bread wheat genotypes showed that advanced lines such
as HAR 1882, HAR 1755, HAR 1698 and commercial cultivar Mitikesignificantly yielded
better than the standard check, Kubsa (Table 11). Advanced lines HAR 3638 and HAR 2096
which were found to be resistant to STB based on corrected percentage necrotic leaf area and
double digit 00-99 scale also had reasonable grain yield compared with Kubsa. The grain
yield data was considered to have an insight into the yield potential of advanced lines which
showed resistance to STB that may be used in transferring resistant genes to high yielding but
susceptible cultivars to STB in the future improvement program.
SUMMARY AND CONCLUSIONS
A combined analysis of variance for the percentage necrotic leaf area showed that the main
effects of the genotypes, environments and the interaction effect were significant (P=O.Ol).
The advanced lines HAR 3640, HAR 3638, HAR 1698, HAR 2096, HAR 3641 and Mitike
were resistant to STB as compared to Laketch.
A multiple linear regression analysis showed that the percentage necrotic leaf area was
significantly affected by days to heading and plant height. The advanced lines indicated
above have true genetic resistance as observed through deviation from the regression of
infection from days to heading and plant height. However, the resistance observed under field
conditions for HAR 3640 was mainly due to escape mech.anisms involving late maturity and
tall plant stature. The performance of the genotypes followed a similar trend for the double
digit 00-99 score. The ranking of genotypes, however, varied between assessment methods.
This study suggested that in screening germplasm for resistance to Septaria tritici blotch,
severity data should be corrected for the effects of days to heading and plant height,
especially when the genotypes are not grouped into maturity classes.
REFERENCES
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Kenya. Ph.D. Thesis. Wageningen Agricultural University. 115 pp.
Camacho-Casas, M.A., Kronstad, W.E., and A.L. Scharen. 1995. Septoria tritici resistance and associations with
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Cordo, c.A., PerHo, A.E., Arriaga, H.O., Bendicto, G., Avila, V. and I.R. de Ziglino. 1994. Resistancia a la
"Mancha Foliar" causado por Septoria trifici en el trigo pan (Triticum aestivum L.). Revista de la Facultad
de Agronomia, la Plata 70:23-26. (Cited in Eyal, 1995).
Dagnachew Yirgu. 1969. Losses due to leaf blotch (Septoria tritici) of wheat. Progress Report on Agricultural
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