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Accueil du site → Doctorat → Ethiopie → Genetic Erosion, Drought Tolerance and Genotype by Environment Interaction of Durum Wheat (Triticum turgidum var durum) in Ethiopia

Haramaya University (2019)

Genetic Erosion, Drought Tolerance and Genotype by Environment Interaction of Durum Wheat (Triticum turgidum var durum) in Ethiopia

Zemede Lemma, Alemayehu ;

Titre : Genetic Erosion, Drought Tolerance and Genotype by Environment Interaction of Durum Wheat (Triticum turgidum var durum) in Ethiopia

Auteur : Zemede Lemma, Alemayehu ;

Université de soutenance : Haramaya University

Grade : Doctor of Philosophy (PhD) in Agriculture (Plant Breeding) 2019

Résumé partiel
Durum wheat is among the major cereal crops in Ethiopia, but its production has been challenged by several factors. Loss of diversity due to genetic erosion, drought stress and lack of stable genotypes due to genotypes by environment interactions have been among the factors that could be mentioned The overall objective of the present study was to estimate genetic erosion, drought stress and genotype by environment interaction on durum wheat. Three approaches ; namely : direct observation ; survey and group discussions were held to estimate genetic erosion and identify its causes in three districts of the central highlands of Ethiopia. Based on direct observation, the loss of genotypes was found to be in Dukem-Akaki (87.5%) followed by Lume (80%) and Gimbichu (60%) districts. Similarly, based on the information from the famers interviewed, the loss of diversity in the study districts was estimated to be 100 % in Ada district, where all farmers’ and old improved durum wheat varieties were lost followed by Lume (93.3%) and Gimbichu (66.7%). Field experiment for the evaluation of 64 durum wheat genotypes obtained from both landrace collections and international sources was conducted in two replications on sandy clay soil (Andoslos) at Debre-Zeit Agricultural Research Center in the 2016 main growing season. Terminal drought had highly significant effect on grain yield per plot, above-ground biomass, spike length, days to heading and grain filling period. Normalized Difference Vegetative Index(NDVI) as a stay green trait at different growth stage was significantly different among genotypes in both sandy clay and clay soils. The results suggested that genotype 63 scored the maximum NDVI value (0.84) at booting stage, in both light textured and black clay soils and started to decline from this onwards. Generally, NDVI allowed identification of better yielding lines. Screening and evaluation of xxii 144 durum wheat genotypes comprising selected landrace collections, global durum wheat collections and released durum wheat cultivars were carried out in two replications on light textured soils at Debre-Zeit Agricultural Research Center in the 2017 dry season under stress and non-stress conditions. Screening and identification of durum wheat genotypes using indices and morpho-agronomic traits were performed. The results of the combined analysis of variance showed that moisture, genotypes and their interaction had highly significant (p≤0.01) effects on grain yield. Significant and positive phenotypic and genotypic correlation coefficients were found between grain yield under low moisture stress condition with indices DRI, REI, GMP, MP and STI, suggesting that these indices would enable identify drought tolerant genotypes. Durum wheat genotypes showed variations in all the traits, except days to heading and anthesis under stressed and non-stressed.

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