No abstract

<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>

Combining ability and gene action 6 half diallel crosses. Results revealed that ability mean squares were significant for all studied additive and nonadditive components in the predominance of additive gene effects for From the GCA effect, it was observed that combiner for all yield component ombining ability and gene action of a set of durum wheat characters were studied using 6 6 half diallel crosses. Results revealed that general (GCA) and specific (SCA) combining were significant for all studied traits, suggesting the importance of both additive and nonadditive components in the inheritance of these traits. Baker ratio indicate the predominance of additive gene effects for the majority of traits studied except grain yield.it was observed that none of the six parents was yield components. Among the fifteen crosses, Zenati-Bouteille/Flamengo x followed by Waha x Ofanto, Waha x Mexicali 75 and Ofanto x Guemgoum Rkhem the greatest positive SCA effect for grain yield. Days to heading index could be used as an indirect selection criterion for better grain yield.selecting early heading genotypes having high fertile tillers number could improve grain