Response of two genotypes of bread wheat (Triticum aestivum), Mahon-Demias (MD) and Hidhab (HD1220), to mature embryo culture, callus production, and in vitro salt and heat tolerance was evaluated. For assessment of genotypes to salt and heat tolerance, growing morphogenic calli were exposed to different concentrations of NaCl (0, 5, 10, and 15 g·L −1 ) and under different thermal stress intensities (25, 30, 35, and 40 • C). Comparison of the two genotypes was reported for callus induction efficiency from mature embryo. While, for salt and heat tolerance, the proliferation efficiency, embryonic efficiency, and regeneration efficiency were used. The results show significant medium and genotype effects for the embryogenesis capacity of calluses induction and plantlets regeneration under saline and thermal stresses. Mahon-Demias showed good callus induction and ability to proliferate and regenerate seedling under heat and salt stress conditions compared to Hidhab. No sizeable differences were observed between the two genotypes at higher salt stress rates. This study will serve as a base line for in vitro screening of several elite wheat cultivars for their ability to induce callus and regenerate plants from mature embryos, and to start selection for tolerance to salinity.

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.

No abstract

An in vitro experiment with two cultivars, Mahon Demias and Hidhab of bread wheat (Triticum aestivum L.) exhibited appreciable callus induction but differed significantly in the capacity of calli proliferation and regeneration under salinity stress; even though Mahon Demias appeared relatively more tolerant than Hidhab. The results indicated the need to optimize a robust protocol for callus induction, maintenance and regeneration before selection process for tolerance to salinity is embarked upon.

Fusarium wilt of date palm (Phoenix dactylifera L.) caused by Fusarium oxysporum f.sp. Albedinis is one of the most destructive diseases in North Africa spicily in Algeria and Morocco. The objectives of this work were the isolation, identification and biocontrol efficacies testing of rhizospheric actinobacteria of medicinal plant Astragalus gombo against fusarium wilt disease in date palm. Five rhizospheric Streptomyces spp. Isolates bi02, bi21, bi24, bi26 and bi28 showed the largest zone of inhibition demonstrating a potent effect against F. oxysporum f.sp. Albedinis and a broad spectrum of antimicrobial activities against the test microorganisms. All these selected isolates produced indol acetic acid (IAA) at different levels, exhibited higher activity of phosphate solubilisation and siderophore production as well as chitinase and protease activities. The inoculation of infected date palm with the five Streptomyces spp. Increased all parameters of growth measured in controlled conditions. The study revealed that the five Streptomyces spp. could be a potential biocontrol agent for controlling palm and also promoting growth of plants.