Adoption of Durum Wheat Cultivar ‘Salim’ with a Technical Package and Its Resilience to Climate Change Impacts in Smallholders: Case of Nebeur/Kef Region, Tunisia

In recent years, there has been an urgent need for local strategies to ensure food sustainability in Tunisia, recognized as a climate change hotspot region. In this context, adaptation measures, including the adoption of high-yielding durum wheat cultivars with adequate agronomical practices, are an important avenue to improving the productivity of the smallholders that represent 80% of Tunisian farmers. Thus, this study highlights the impact of (i) the adoption of the recently marketed durum wheat cultivar ‘Salim’ as compared to the common cultivar ‘Karim’ and the transfer of a technical package to 11 farmers in the Nebeur delegation/Kef-Tunisia (semi-arid region) during the 2013/2014 and 2014/2015 cropping seasons, and (ii) climate change on the expected mean grain yield and biomass by 2070, using the CropSyst agronomic cultivation model based on multi-year crop simulations run with a daily weather series (2020–2070). The adoption of ‘Salim’ with the recommended package, compared to ‘Karim’ with the farmer practices, significantly increased the grain yield (37.84%) and biomass (55.43%). Otherwise, the impact of the 0.8 °C temperature rise on the potential yields and biomass over the next 51 years was positive. Contrary to expectations, the yield increases for the two cultivars were very close, but the yield of ‘Salim’ (36.02 q ha−1) remains much higher than that of ‘Karim’ (23.34 q ha−1). On other hand, ‘Salim’ experienced a higher increase for biomass compared to that of ‘Karim’. These results indicate that the adoption of the ‘Salim’ cultivar with its technical package might be considered as a strategy of adaptation to Nebeur conditions and to future climate change events.

CDC Credence durum wheat

CDC Credence durum wheat is adapted to the durum production area of the Canadian prairies. This conventional height durum wheat cultivar combines high grain yield potential with high grain and pasta color and low grain cadmium. CDC Credence is resistant to leaf, stem, and stripe rusts and common bunt and demonstrated end-use quality suitable for the Canada Western Amber Durum class.

CDC Covert durum wheat

CDC Covert durum wheat is adapted to the durum production area of the Canadian prairies. This conventional height durum wheat cultivar combines high grain yield with acceptable time to maturity, disease resistance, test weight, and end-use suitability. CDC Covert is resistant to prevalent races of leaf and stem rust, has excellent common bunt resistance, and demonstrated end-use quality suitable for the Canada Western Amber Durum class.

CDC Defy durum wheat

CDC Defy durum wheat is adapted to the durum production area of the Canadian prairies. This conventional height durum wheat cultivar combines high grain yield, acceptable time to maturity, test weight, and grain protein concentration. CDC Defy is resistant to prevalent races of leaf and stem rust, has excellent common bunt resistance, and demonstrated end-use quality suitable for the Canada Western Amber Durum class.

Genetic and transcriptional dissection of resistance to Claviceps purpurea in the durum wheat cultivar Greenshank

Key message Four QTL for ergot resistance (causal pathogen Claviceps purpurea) have been identified in the durum wheat cultivar Greenshank. Abstract Claviceps purpurea is a pathogen of grasses that infects flowers, replacing the seed with an ergot sclerotium. Ergot presents a significant problem to rye, barley and wheat, in particular hybrid seed production systems. In addition, there is evidence that the highly toxic alkaloids that accumulate within sclerotia can cross-contaminate otherwise healthy grain. Host resistance to C. purpurea is rare, few resistance loci having been identified. In this study, four ergot resistance loci are located on chromosomes 1B, 2A, 5A and 5B in the durum wheat cv. Greenshank. Ergot resistance was assessed through analysis of phenotypes associated with C. purpurea infection, namely the number of inoculated flowers that produced sclerotia, or resulted in ovary death but no sclerotia, the levels of honeydew produced, total sclerotia weight and average sclerotia weight and size per spike. Ergot testing was undertaken in Canada and the UK. A major effect QTL, QCp.aafc.DH-2A, was detected in both the Canadian and UK experiments and had a significant effect on honeydew production levels. QCp.aafc.DH-5B had the biggest influence on total sclerotia weight per spike. QCp.aafc.DH-1B was only detected in the Canadian experiments and QCp.aafc.DH-5A in the UK experiment. An RNASeq analysis, undertaken to identify wheat differentially expressed genes associated with different combinations of the four ergot resistance QTL, revealed a disproportionate number of DEGs locating to the QCp.aafc.DH-1B, QCp.aafc.DH-2A and QCp.aafc.DH-5B QTL intervals.

Response of the Durum Wheat Cultivar Um Qais (Triticum turgidum subsp. durum) to Salinity

The threat of land degradation by salinization in Jordan has been increasing over the last decades. Therefore, information about the response of local cultivars to salinity is needed to help farmers choose the most productive cultivars for areas with salt-affected soils. A recently released durum wheat cultivar Um Qais (Triticum turgidum subsp. durum) has shown to be productive under normal conditions but to date there are no known studies on its tolerance to salinity. Two experiments were conducted to investigate the response of Um Qais cultivar to salinity. A field experiment was carried out in the Jordan Valley, which is known for its hot, dry climate during the summer and low rainfall and moderate temperature during the winter. Three water salinity levels (S): S1 (2 dS m−1), S2 (4 dS m−1), and S3 (8 dS m−1) with three irrigation amounts (R) (control = 120% (R1), 100% (R2), and 70% (R3)) were used in the field. A greenhouse experiment was conducted using four levels of saline water (S): S1 (0.65 dS m−1), S2 (4 dS m−1), S3 (8 dS m−1), and S4 (10 dS m−1). In both experiments, the leaf area index (LAI) and canopy height were measured during three growth stages, tillering, flag leaf, and maturity. The number of grains, grain yield, and above-ground biomass were measured after harvesting while soil salinity and pH were measured every three weeks during the growing season. The results showed that the maximum reduction in yield was of the 28% in the field experiment when the average soil salinity was of 6.8 ± 1.1 (standard error) dS m−1 at the middle stages of the season. Significant changes were shown in the treatments of the field experiments for maximum LAI, number of grains, and aboveground biomass, but not for plant height. For the greenhouse treatments, about 60% of the maximum grain yield was obtained when the average soil salinity was 9.94 ± 1.89 dS m−1 at the middle stage. Grain yield was the most sensitive parameter to the increase in soil salinity during the season. According to the findings of both experiments, Um Qais can be cultivated in moderately saline soils.