Relationships among agronomic traits and grain yield were investigated in 56 genotypes of durum wheat (Triticum durumDesf.). The results indicated the presence of sufficient variability nearly for all measured traits. Heritability and expected genetic gain varied among traits. Aboveground biomass, harvest index, and spike number were the most grain yield-influencing traits. Early genotypes showed above-average grain and biological yields, spike number, and lower canopy temperature. Assessed genotypes were clustered into three groups which differed mainly for biological, economical, straw, and grain yields, on the one hand, and plant height, chlorophyll content, and canopy temperature, on the other hand. Selection for direct use from clusters carrying best combinations of yield-related traits and crosses to be made between genotypes belonging to contrasted clusters were suggested to generate more variability. Selection preferentially for spike number, biological yield, harvest index, and canopy temperature to accumulate favorable alleles in the selected entries for future uses is suggested.

No abstract

-The paper presents the results of the chromosomal counting of 59 species of genus Eucalyptus among which 55 are newly examined. All these species possess 2n = 22 including the four species for which the numbers 2n = 20, 24 and 28 have been reported. The number 2n = 24 previously raported in 9 species appears to result from a break of the chromosome first pair very often observed in the Eucalyptus in the metaphase and especially premetaphase stage. Although some contradictory cases of aneuploid have been reported in the literature, the large homogeneity of the chromosome number 2n = 22, now known for 135 (33.5%) distinct species, makes the genus Eucalyptus to be considered as a vast caryologic continuum who probably adopts a process of evolution based fundamentally on chromosome alterations.

La répartition des précipitations en différentes fractions d’égouttement, écoulement et interception est la première interaction entre le cycle de l’eau et la forêt. Ces fractions ont été évaluées pour une période de trois années successives sous le couvert de Quercus ilex L. dans la chênaie de Hamla dans les Aurès par un dispositif de recueil spécifique pour chaque fraction : sous couvert pour l’égouttement, scellé sur les troncs pour l’écoulement et installé sur un sol nu pour les précipitations. Les résultats ont montré que le taux des précipitations qui arrivent par égouttement se situe en moyenne à 57,4 % des précipitations. L’écoulement ne représente en moyenne qu’une faible fraction (6,7 %) des précipitations. Quant à l’interception, elle est très forte et elle représentait en moyenne 35,8 % des précipitations. La variabilité interannuelle de l’égouttement et de l’interception est importante. Elle est largement dépendante des précipitations journalières incidentes. Les relations entre les précipitations, l’écoulement et l’égouttement dans la station étudiée ont été appréciées par des régressions linéaires qui ont montré de fortes corrélations entre les différentes fractions d’eaux et les précipitations (R2 varie entre 0,74 et 0,99).

Nutrient provisions through precipitation and throughfall represent major factor of the sustainability of the forest ecosystem. Nevertheless, data related to this aspect are non-existent in Algeria. Precipitation and throughfall volumes and their contributions in NPK elements were evaluated between 2012 and 2013, in a green oak coppice at Marconna in Aurès (eastern Algeria). Precipitation volumes were evaluated by the placement of 10 containers in a bare soil. To quantify the throughfall, four containers were installed under the canopy of each tree among 25 selected trees. Water samples taken from previously rinsed plastic bottles with distilled water were kept away from light and transported to the laboratory for volume estimation and chemical analysis, as quickly as possible. After rapid filtration, samples became ready for NPK analysis. Various devices and chemicals were used for the measurements of NPK elements in the laboratory. Kjeldahl's method, colorimetry and flame photometry were used for quantifying total nitrogen, phosphorus and potassium respectively. The results showed that annual rainfall amounts varied between 223,9 and 289,6 mm, whereas the annual throughfall was 127,1 mm for 2012 and 189,8 mm for 2013.Besides, the annual quantities of N, P and K returned to the soil by the rainfall ranged from 5,05 to 7,62 kg/ ha/year. However, the throughfall results showed that the coppice accumulated amounts of N, P and K elements varying between 4,08 and 5,47 kg / ha / year. On average, nitrogen was the most provided element. It represented 47,07%.