Genetic parameters such as leaf relative water content, leaf chlorophyll content, plant height, above-ground biomass, harvest index, grain yield, and grain yield components of Bousselam/Mrb5 durum wheat (Triticum durum Desf.) cross were estimated based on generation means analysis. A, B, C, and D scaling and Chi-square (χ2) tests revealed the inadequacy of the simple additive-dominance model. This result suggests the presence of digenic epistasis for most studied traits; the duplicate epistasis was present for relative water content, above-ground biomass, and grain yield; and complementary epistasis was observed for chlorophyll content. Significant genotypic correlation coefficients appeared among grain yield, relative water content, and above-ground biomass. This suggests useful indirect selection criteria to improve simultaneously these traits, which showed significant heritability. It can be concluded that the traits investigated show a complex genetic behavior, which implies that early selection would be less efficient; therefore, it is recommended delaying the selection to advanced generations to benefit from the reduction of non-fixable genetic variation and exploit transgressive segregators due to the significant interaction additivity×additivity (i) of the gene and duplicated epistasis.

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<p>The present study aimed to investigate the extent of variability and relationships between grain yield and morpho-physiological durum wheat traits. Sufficient variability was observed for most characters. Based on stress indices, either widely or specifically, adapted lines were identified. Path analysis pointed out to above ground biomass, harvest index, spike fertility and spike number as yield determinants, suggesting that these traits are of interest in the breeding program. The measured traits were classified within 6 principal components accounting for 79.45 % of the total variation. Breeding lines dispersed along first principal component exhibited substantial differences in performance and stress tolerance abilities. Cluster C3 lines were high yielding and stress tolerant. From this cluster, lines L24 and L14 were scored as the best for 7 and 5 traits out of 17 characters, respectively. Both lines are proposed for release and as parents in crosses to take advantage of their desirable characteristics. The results indicated that physiological traits were unrelated to each other and to morphological traits making difficult the concomitant selection for yield and stress tolerance driven by these traits. Complexes crosses, between parents carefully chosen for these specific characteristics, are necessary to enhance favorable genetic linkage and to generate new basic segregating populations with high genetic variability for these traits.</p>

The experiment was conducted during three growing seasons and two planting dates. The cultivation site is placed at the ITGC Setif characterized by a semi-arid environment. The objective of the study is the analysis of phenotypic variability of traits measured for 15 varieties of durum wheat, through the average effects, to decline the ways, characters and varieties could play in favour of performance under the constraining semi-arid conditions. The year effect indicates that given the difficulty of predicting the performance enabled by years, it then makes sense to go straight for this performance within genotypes. Analysis of the effect genotype highlights characters connected to performance and is the Setifis variety that lends itself well. For the effect of sowing date, it is that early sowing promotes a better expression of the characteristics compared to late sowing.

This research was conducted to screen and analyse the variability within twenty F 3 populations of bread wheat (Triticum aestivum L.) generated by Line x Tester mating design.The results indicated the presence of sufficient variability within and between F 3 populations for the eight measured variables, which represent plant phenology, physiology, yield and yield components. Different populations have been identified to improve the measured variables separately. The number of spikes appeared to be the most important determinant of grain yield.PCA and cluster analyses indicated that the Acsad 1069 /El Wifak and Acsad 1135 /Hidhab, with a relatively high grain yield, aboveground biomass and 1000 grains weight, are the best F 3 populations to improve the productivity. However, Acsad 899 /Rmada and Acsad 1135 /Rmada populations were earlier and had a low number of spikes. These populations had also favorable genes for heat tolerance. Keywords ABSTRACTThis research was conducted to screen and analyse the variability within twenty F 3 populations of bread wheat (Triticum aestivum L.) generated by Line x Tester mating design.The results indicated the presence of sufficient variability within and between F 3 populations for the eight measured variables, which represent plant phenology, physiology, yield and yield components. Different populations have been identified to improve the measured variables separately. The number of spikes appeared to be the most important determinant of grain yield.PCA and cluster analyses indicated that the Acsad 1069 /El Wifak and Acsad 1135 /Hidhab, with a relatively high grain yield, aboveground biomass and 1000 grains weight, are the best F 3 populations to improve the productivity. However, Acsad 899 /Rmada and Acsad 1135 /Rmada populations were earlier and had a low number of spikes. These populations had also favorable genes for heat tolerance.