Abstract:Two durum wheat (triticum durum Desf.) cultivars were tested for salt and drought tolerance at germination, seedling emergence and early seedling growth in NaCl and PEG-8000 solutions of different osmotic potentials . Daily and final germination and emergence percentage, as well as germination and seedling emergence rate, seedling growth, fresh and dry weight were recorded under controlled conditions. Results showed that germination and emergence rates were delayed by both solutions in both cultivars, but Omrabia showed higher germination and emergence rates than BD290273 in NaCl while BD290273 was less affected by NaCl and PEG solutions at the emergence stage. Sodium chloride had a lesser effect on both cultivars in terms of germination rate, emergence rate, final germination and emergence percentage than did PEG-8000. This conclusively proves that the adverse effect of PEG-8000 on germination, emergence and early seedling growth was due to the osmotic effect rather than to the specific ion. Seedling growth was reduced by both stresses. However, NaCl usually caused less damage than PEG to durum wheat seedlings, suggesting that NaCl and PEG acted through different mechanisms.

In water-limited areas of Tunisia, more than 30% of subsurface water used for irrigation is saline water, leading to a long-term salinization and degradation processes. To prevent the problems and to minimize the negative impact of using saline water, selection of proper germplasm as well as integrated soil and water management are essential. Understanding the diversity for salt tolerance in barley (Hordeum vulgare L.) genotypes will facilitate their use in genetic improvement. Our objectives were to evaluate, in green, house-salt tolerance for 14 barley cultivars under three different salinity levels: (tap water with an Ec = 0.73 dSm(-1), tap water with 102 mM of NaCl, Ec = 10.76 dSm(-1) and tap water with 151 mM of NaCl, Ec = 15.38 dSm(-1)), and quantify genetic variation based on salt tolerance index, morphological traits, molecular and factorial analysis of correspondence (FAC). The study was conducted in a randomized complete block design arranged as a split plot. The results indicate a great genetic variability to salt tolerance among used barley genotypes. Consequently, it is possible to identify superior cultivars, and evaluate the genotypic performance under salinities conditions. In addition, results obtained were confirmed by clustering made by SSR tool on the base of DNA analysis, which is compatible with the arrangement obtained with statistical method.

An experimental study was carried out under semi controlled conditions at National Agronomic Research Institute of Tunisia in Ariana experimental station. Eight main Tunisian Durum wheat (Triticum turgidum L.) varieties were grown under salinity conditions. The objectives of this research were to compare the behaviour of the varieties under salt stress. Many agronomic and physiological traits were evaluated under both saline (10 g NaCl/l) and non saline conditions (control). Results showed that salinity negatively affected all of the studied parameters. The tiller number, chlorophyll contents, height growth rate, shoot dry weight, spikes per plant, 1000-grain weight and total grain yield were significantly affected by salinity. However the plant height, spikelets per spike and grains per spike were much less affected by salinity. Correlation studies showed significant positive and negative correlations between salt tolerance indexes of different evaluated parameters. These results strongly suggest that the number of fertile tillers and shoot dry weight might be useful for salinity tolerance improvement programs of the analyzed genotypes.

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Irrational use of chemical method for crop protection, presents increasingly serious risks for human health and the environment. Droplet size and meteorological parameters are key factors to both environmental contamination and pest control efficacy. The objective of this study is to assess the impact of the nozzle use parameters, the operating pressure and the wind speed on droplet foliage deposition (retention) and soil deposition (losses), when treating artichoke. Several combinations were tested in a wind tunnel and in the field, under Mediterranean microclimatic conditions, using a fluorescent dye as a substitute for pesticide. Multiple regression models were built from tunnel data to predict foliage deposition and soil deposits, with determination coefficients of 0.96. Thus, models are able to simulate pesticide deposition on artichoke leaves and soil deposition, depending on sprayer parameters and wind speed. Foliage deposition and soil deposits rates ranged from 30 to 52% and 26 to 57% respectively for anti-drift nozzle. For conventional nozzle, rates varied from 20 to 38% and 31 to 62%. To improve retention and reduce spray losses, it is recommended to choose a medium droplet size when using an anti-drift nozzle, in conjunction with medium nozzle size, medium pressure and reduced wind speed.