Mitiku, Dawit (2008) Genotype X Environment Interaction of Imiadazolinone Resistant Maize Genotypes for Yield Under Striga Infestation. Masters thesis, Addis Ababa University.
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PDF (Genotype X Environment Interaction of Imiadazolinone Resistant Maize Genotypes for Yield under Striga Infestation)
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Abstract
Twenty-five imidazolinone resistant (IR) maize genotypes were laid down in 5x5 simple lattice design with 2 replications at six striga infested and five striga free environments during 2006/07 cropping season. The objectives of the study were to evaluate IR maize genotypes for grain yield and adaptability under striga infestation and free field conditions, to determine the magnitude of genotype-by-environment interaction (GEI) of IR maize genotypes for grain yield, to determine stability of yield performance among the IR maize genotypes and identify the stable genotype(s) and those with adaptation to specific environments and to study the correlation among various stability parameters. For trials where successful striga infestation was achieved, yield was reduced on average from 8.62 to 26.87 Q/ha. The average percent reduction in yield for all the IR maize genotypes was 40.40% whereas for the standard check, WH-403 it was 65.00%. The highest percent reduction due to striga infestation was observed on WH-403 at Alupe (79.00%) and Kibos (75.54%). Under striga free condition, WH-403 gave the highest mean yield of 42.28 Q/ha but with only 3.37% yield advantage over the highest yielding IR genotype, INTA/CML390/373 while under striga infested field the highest yielding IR genotype, CML445/390/373 had a yield advantage of 86.50% over WH-403 showing the superiority of IR maize genotypes under striga infestation. Combined ANOVA revealed highly significant effects of the environments, genotypes and GEI. The presence of significant GEI showed the inconsistency in performance of maize genotypes across the 11 environments. Six statistical methods were conducted to determine yield stability. Results of additive main effects and multiplicative interaction ( AMMI) analysis showed that out of 11 interaction principal component axis (IPCAs) only the first two IPCAs were found to be highly significant and cumulatively contributed 58% of the total GEI while linear regression explained only 6% of the total GEI. Spearman’s coefficient of rank correlation between mean yield and regression coefficient ( i ), stability variance (2i), ecovalence (Wi) and deviation from regression ( 2 di ) was positive and significant, but there was non-significant correlation between mean yield and coefficient of variation (CV) and AMMI stability value (ASV). Since ASV explains interaction effects and provides agronomically meaningful insights into the data structure, it is better if used as stability measure for reliable selections of stable genotypes. Based on most of the stability parameters estimated, the three-way cross maize hybrid, CML78/390/202 and the late maturing maize OPV, ECA-144, were found to be the most stable.
| Item Type: | Thesis (Masters) |
|---|---|
| Uncontrolled Keywords: | AMMI, ASV, GEI, Maize, IR, Stability, Striga |
| Subjects: | Q Science > Q Science (General) Q Science > QH Natural history > QH301 Biology Q Science > QH Natural history > QH426 Genetics Q Science > QK Botany |
| Divisions: | Africana |
| Depositing User: | Selom Ghislain |
| Date Deposited: | 01 Oct 2018 14:23 |
| Last Modified: | 01 Oct 2018 14:23 |
| URI: | http://thesisbank.jhia.ac.ke/id/eprint/5760 |
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