VARIABILITÉ PHÉNOTYPIQUE ET SÉLECTION DES CARACTÈRES AGRONOMIQUES DU BLÉ DUR (Triticum durum Desf.) SOUS CONDITIONS SEMI-ARIDES

Genetic improvement of agronomic traits related to yield performance and adaptation to the production environments is conditioned by the presence of phenotypic variability of the targeted characters in the plant material subjected to selection. This research was conducted to assess the magnitude of phenotypic variability, the heritability and the expected genetic gain of selection of agronomic traits in 18 durum wheat (Triticum durum Desf) varieties and segregating lines. The results showed the presence of significant variability for the measured traits. The degree of genetic determination had values greater than 70% for the duration of the vegetative phase and plant height, and below 50% for yield and aboveground biomass. The expected genetic gain ranged from 4.8% for the duration of the vegetative phase to 45.9% for grain yield. Single-character selection identified 6 desirable genotypes which brought increases of 14.9% in harvest index, 3.7 g in 1000 kernel weight, 4.8% in relative water content, and declines of 18.6% in percent cells injury, 2.1 g in yield per plant, 2.1 cm in spike length, and 12.9 grains per spike, and a gain of 1.7 spikes associated to 8.8 g of biomass. Relatively to Bousselam, the check cultivar, the selected lines brought a grain yield advantage ranging from 53.8 to 161.5%. This yield gain is associated with a desirable improvement in heat stress tolerance, and an undesirable reduction in thousand kernel weight. The study of th

DÉTERMINISME GÉNÉTIQUE DES CARACTÈRES MORPHO-PHYSIOLOGIQUES LIÉS AU RENDEMENT CHEZ LE BLÉ DUR EN ZONE SEMI-ARIDE DES HAUTS PLATEAUX SÉTIFIENS, ALGÉRIE

The present investigation was undertaken to study the inheritance pattern of morpho-physiological traits: relative water content, excised leaf water loss, flag leaf area and membrane stability, in an F3 population of durum wheat (Triticum durum Desf.). The results reflected a satisfactory range of variability in the evaluated traits. Range magnitude of the four traits represented the equivalent of 5.0 to 11.4 times the least significant difference at 5% level. Transgressors with variable frequency were observed for all the measured traits. In fact 25% of the F3 lines showed a relative water content greater than 85%, 3% has a flag leaf area superior to 26 cm², 8% had a low leaf water loss rate and 11% expressed a low electrolyte leakage rate, suggesting a high membrane stability. Medium to high broad sense heritability estimates were noted for the measured traits. Medium to high genetic gain expressed as percent of the base population mean was observed, taking the following values: 11.0%, 24.0%, 68% and 88%, for relative water content, flag leaf area, excised leaf water loss rate, and percent of cell injury, respectively. Altogether, the obtained results indicated that the studied cross population would be of interest in the breeding program and an effective progress can be made through selection of these morpho-physiological characters to enhance stress tolerance and grain yield potential

VARIABILITÉ PHÉNOTYPIQUE ET SÉLECTION DES CARACTÈRES AGRONOMIQUES DU BLÉ DUR (Triticum durum Desf.) SOUS CONDITIONS SEMI-ARIDES

Genetic improvement of agronomic traits related to yield performance and adaptation to the production environments is conditioned by the presence of phenotypic variability of the targeted characters in the plant material subjected to selection. This research was conducted to assess the magnitude of phenotypic variability, the heritability and the expected genetic gain of selection of agronomic traits in 18 durum wheat (Triticum durum Desf) varieties and segregating lines. The results showed the presence of significant variability for the measured traits. The degree of genetic determination had values greater than 70% for the duration of the vegetative phase and plant height, and below 50% for yield and aboveground biomass. The expected genetic gain ranged from 4.8% for the duration of the vegetative phase to 45.9% for grain yield. Single-character selection identified 6 desirable genotypes which brought increases of 14.9% in harvest index, 3.7 g in 1000 kernel weight, 4.8% in relative water content, and declines of 18.6% in percent cells injury, 2.1 g in yield per plant, 2.1 cm in spike length, and 12.9 grains per spike, and a gain of 1.7 spikes associated to 8.8 g of biomass. Relatively to Bousselam, the check cultivar, the selected lines brought a grain yield advantage ranging from 53.8 to 161.5%. This yield gain is associated with a desirable improvement in heat stress tolerance, and an undesirable reduction in thousand kernel weight. The study of th

DÉTERMINISME GÉNÉTIQUE DES CARACTÈRES MORPHO-PHYSIOLOGIQUES LIÉS AU RENDEMENT CHEZ LE BLÉ DUR EN ZONE SEMI-ARIDE DES HAUTS PLATEAUX SÉTIFIENS, ALGÉRIE

The present investigation was undertaken to study the inheritance pattern of morpho-physiological traits: relative water content, excised leaf water loss, flag leaf area and membrane stability, in an F3 population of durum wheat (Triticum durum Desf.). The results reflected a satisfactory range of variability in the evaluated traits. Range magnitude of the four traits represented the equivalent of 5.0 to 11.4 times the least significant difference at 5% level. Transgressors with variable frequency were observed for all the measured traits. In fact 25% of the F3 lines showed a relative water content greater than 85%, 3% has a flag leaf area superior to 26 cm², 8% had a low leaf water loss rate and 11% expressed a low electrolyte leakage rate, suggesting a high membrane stability. Medium to high broad sense heritability estimates were noted for the measured traits. Medium to high genetic gain expressed as percent of the base population mean was observed, taking the following values: 11.0%, 24.0%, 68% and 88%, for relative water content, flag leaf area, excised leaf water loss rate, and percent of cell injury, respectively. Altogether, the obtained results indicated that the studied cross population would be of interest in the breeding program and an effective progress can be made through selection of these morpho-physiological characters to enhance stress tolerance and grain yield potential

Appréciation de la qualité technologique d’une collection de blé tendre (Triticum aestivum L.) cultivée en Algérie

The wheat quality requirements are diverse and depend on the wheat species cultivated, the expected end-use product and the environment in  which it is produced. In this study, 34 bread wheat varieties were evaluated for several physico-chemical and rheological parameters including  thousand-kernel weight, grain moisture content, grain protein content, wet and dry gluten contents, sedimentation Zeleny test value and Hagberg  falling number. It was observed that the extreme min and max values vary depending on the genotype evaluated and the test used, suggesting the  difficulty of grouping all the desirable characteristics in the same genetic background. The results also show that there was a positive correlation of  the Zeleny sedimentation value with grain moisture content, protein content, wet and dry gluten at phenotypic and genotypic levels. This test can  be used to predict the wheat technological quality during the milling process. Furthermore, this study offers to breeders’ valuable information  which, in future breeding programs, can be used to develop high yielding and adapted genotypes, and appreciated by the rheological and   technological quality of their end-use product