Growth and yield of two Tunisian pepper varieties were evaluated for their salt and water stress tolerance under the salinity levels of 0, 30 and 60 mM NaCl and water stress with 50% depletion of available soil water. The treatment were applied 10 days after transplanting and continued up to plant harvesting. The results of this study indicated that growth, leaf area, yield and marketable fruits of the pepper genotypes were clearly decreased when the plants were exposed to water stress, salt stress and, combined salt and water stress conditions. Reduction is more noticeable in 60 mM NaCl salinity combined with water stress.

Use of doubled haploïdes allows to shorten considerably the cycle of classic selection and to obtain quickly a stable homozygotie. However, regeneration of albino plants, particularly for cereal, constitutes the major problem of this approach. Obtaining haplodiploïdes by in vitro culture of not fertilized ovaries is determined by numerous factors biological as physical or chemical. Our work concerned the optimization of the answer gynogenetique of three varieties of durum wheat (Cocorit, Isly, Jori) cultivated on two different media (M1 et M2) and subjected to a cold pre-treatment at 4 ° C for 7, 11 and 15 days.This work has demonstrated that genotypes interact strongly with pre-treatment duration and with induction medium composition. Thus, a beneficial effect of thermal pre-treatment was noted on the induction of embryos and production of callus, and also on the quality of regenerating. For the regeneration of green plants, the response of genotypes varied with the induction medium composition and with cold pre-treatment period. Indeed, M1 medium was favourable for Cocorit and Jori varieties but with different incubation duration. For cons, M2 medium gave better results with Isly genotype for 7 days incubation.

Drought and salinity are the major problems of Mediterranean agriculture. From an agronomic point of view, adaptation to stress is the ability of a plant to maintain reasonable yields. Various physiological traits related to stress tolerance (relative water content and chlorophyll content) and their impact on yield components were studied in Sorghum (Sudan Grass III).
Experimental design consists of five treatments: a control (100% ETM = 1 g / l), two water regimes (70% and 35% ETM) and two salt diets (3g / l and 6g / l).
Results showed that under moderate water stress, the relative water content and chlorophyll index have decreased slightly and penalized yield components. In response to severe stress, relative water content dropped from 89% to 78% and chlorophyll index fell by about 38% which acted unfavorably on all yield components.
Different intensity of salinity generates a slight increase in TRE but decreased chlorophyll content and size of main panicles.
All the parameters studied shows that there are positive correlations between plant water status and its yield: sorghum maintains high TRE under salinity and drought which indicating that this plant is of type "stay green" that keeps green and photosynthetically active leaves to have reasonable yields under abiotic stresses.

Laboratory study was conducted to investigate allelopathic effects of seed aqueous extract of Pennisetum glaucum on seedling growth of three cereals; Avena sativa, Triticum durum and Hordeum vulgare Different levels of P. glaucum seed aqueous extracts concentrations (0%, 2%, 4%, 8% and 10%) were used to test its effect on the studied species. Results revealed significant allelopathic effects of seed aqueous extract of P. glaucum on radicle, coleoptile and total plant lengths. However, it was found that Avena sativa was the most susceptible and Triticum durum was the less sensitive on seed aqueous extract of Pennisetum glaucum.