Tunisia is considered as a diversification centre of durum wheat (Triticum durum Desf.) and barely (Hordeum vulgare). It is characterised by large genetic diversity; however, several genotypes are in the process of disappearance. The safeguard and rehabilitatation of this genetic inheritance requires genetic characterisation, evaluation and in-situ and ex-situ conservation. In this context, a local collection of thirty durum wheat accessions was evaluated using agronomical traits. Three other phenological traits: days to maturity, days to heading and filling period were evaluated. The phenotypic diversity was determined by the Shannon-Weaver diversity Index (H') revealing that number of kernel/spike (H'=0.91), yield (H'=0.89), plant height (H'=0.87) and thousand kernel weight (H'=0.86) had the highest diversity index. Flag leaf area (H'=0.32) showed the weakest index. This germplasm presented average diversity (0.77) showing a large genetic variability. Correlations between traits showed a significant positive relation between yield and spikeless tillers/plant (0.90), thousand kernel weight (0.39), plant height (0.35) and flag leaf area (0.36), suggesting the usefulness of these parameter for selecting for improving grain yield. The components analysis explained 59.61% of total variability and led to identification of a group of accessions Jeneh kotifa 1, Jeneh kotifa 2, Jeneh kotifa 3, Sbei glabre, Hamira 1, Hamira 2, Biskri glabre, Mahmoudi, Biskri glabre AP2, Swabaa Elgia, Sbei, and Mahmoudi glabre showing the best agronomical characteristics. These genotypes can, therefore, be used as parents for the improvement of durum wheat.

The objective of this work was to produce doubled haploid plants from durum wheat through gynogenesis using unpollinated ovary culture of three local Tunisian genotypes (Jenah Khotifa, Hmira, Azizi) and three improved cultivars (Karim, Khiar, Razzek). A total of 12,000 unpollinated ovaries were cultured in this study. Spikes were either pretreated at 4°C for 14 days or at 4°C in a mannitol solution (0.3 M) for 7 days. Induction was performed using two media. We showed that ovary development, callus and plantlet regeneration was influenced significantly by genotype and growth conditions. The highest regeneration frequency was obtained when the microspore population was in the late mononucleate to binucleate stage. Our results suggested that the cold pretreatment for 14 days was more efficient than the cold treatment in a mannitol solution. Furthermore, the addition of 2,4-D, vitamins and glutamine, and the use of maltose as sugar source in media improved the ovary culture. When the unpollinated ovaries were cultured under the conditions found to be optimal in the present study, a total of 84 plants were produced, all green and haploid.

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This study presents the first report comparing the efficiency of microspore culture, gynogenesis and durum wheat × maize crosses for haploid plant production from three durum wheat genotypes (Razzek, Karim and Jneh Khotifa). The results showed that the best induction, calli or embryos formation and plant regeneration rates for the three genotypes were obtained with gynogenesis (47.2, 7.6, 0.8%), followed by interspecific crosses (33.1, 1.7, 0.4%) and isolated microspore culture (8.2, 0.05, 0.01%). Interestingly, all plants regenerated by gynogenesis and durum wheat × maize crosses were green whereas all plants obtained by isolated microspore culture were albino. In the haploid production system, all steps of the process are important for the three methods. The critical steps that have greatly reduced the number of regenerated haploid plants were induction, embryogenesis and regeneration for microspore culture, forming and regeneration of calli or embryo and haploid regeneration for interspecific crosses and gynogenesis. Genotypes with good capacity of induction have not necessarily a good capacity of haploid plantlets regeneration and vice-versa. However, calli or embryos formation seems to be an indicator of the haploid production. Overall, Razzek showed a good ability to produce haploids using the three methods. Each haplomethod showed a specific advantage. Although gynogenesis is the less used method for durum wheat, it has proved to be a successful approach for green haploid plant production.