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A three years survey and monitoring studies (2013–2014–2015) were carried out through 4 regions of north Tunisia in order to follow the evolution of the distribution, the frequency of occurrence and damage caused by the Hessian fly Mayetiola destructor (Say) to bread wheat (Triticum aestivum L.) and durum wheat (Triticum durum Desf). Moreover, the effectiveness of resistance genes H3, H5, H6, H7, H8, H9, H10, H11, H12, H13, H14, H15, H22, H23, H25 and H26 to protect wheat from Hessian fly attack was assessed in natural field and under controlled laboratory conditions at INRAT‐Kef Station. Results showed that Hessian fly was detected in 60.33% and 51.5% of all sampled durum and bread wheat fields, respectively. This pest was more frequent with a higher percentage of infestation in semi‐arid regions. Indeed, during 2013, infestation rate attained 12.39% in Kef region against 0.9% registered in Bizerte region. In order to update information about the annual number of generations, we surveyed the population dynamic of Hessian fly in Kef region. Three generations of the fly were counted annually on wheat, with two complete and one incomplete generation. This insect affects host plant growth at different developmental stages. Plant height was the most affected parameter followed by shoot dry weight and tiller number. Field investigations on host resistance revealed that among the 16 tested resistance genes, and only three were strictly effective (H22, H25 and H26). The resistance genes H5, H9, H13 and H9H13 have also conferred high levels of protection against Hessian fly. This work indicated that H22, H25 and H26 genes could be incorporated into Tunisian wheat varieties and released to farmers to manage the threat due to Hessian fly attacks. [ABSTRACT FROM AUTHOR]

Wheat is a staple crop in Tunisia, but little is known about the response of Tunisian durum wheat (Triticum turgidum ssp. durum) and bread wheat (Triticum aestivum L.) to water stress. In semi-arid regions, where cereals are concentrated, grain yield is subject to water deficit especially due to variability in rainfall. Therefore, the objective of this study was to evaluate the response to water stress of three durum wheat (Mâali, Nasr and Salim) and two bread wheat (Tahent and Utique) varieties. The experimental design was a complete randomized block, water treatments were rainfed conditions (T0) and irrigation applied at the tillering and flowering stages (T1, control) with three replications per treatment, and data was analyzed by ANOVA and Tukey test to compare treatments means (p≤0.05). Variables analyzed were grain yield and yield-related components: plants per square meter (NP), tillers per square meter (NT), ears per square meter (NE), seed per ear (NSE) and 1000-kernel weight (TKW). NP, NE, NSE and TKW were significantly affected by water stress, but there was no change on NT. Seed yield was weakly correlated with NE (r=0.376) but significantly correlated with NSE (r=0.604) and NP (r=0.639). Supplemental irrigation increased grain yield by 74.4 %, 42.3 %, 36.1 %, 33.7 % and 24.5 % for Utique, Tahent, Nasr, Maâli and Salim, respectively, compared to control. Four drought tolerance indices, stress tolerance index (STI), stress tolerance (TOL), stress susceptibility index (SSI), and mean productivity (MP), were assessed and were adjusted based on grain yield under drought (Ys) and normal (Yp) conditions. A positive and significant correlation between Ys and Yp with SSI and PM, respectively, indicate that they are the most suitable variables to select wheat genotypes in drought stress. These indices were able to screen a drought-tolerant genotype (Nasr), which showed the highest STI (1.10). In contrast, Salim showed the lowest STI (0.47) and was considered to be a drought-susceptible genotype. [ABSTRACT FROM AUTHOR]