Reaction of the Tunisian improved durum wheat cultivars to main fungal foliar diseases under field conditions

Septoria tritici blotch (STB), tan spot (TS), stripe rust or yellow rust (YR), and brown rust or leaf rust (LR) are the major fungal leaf diseases reducing the productivity and quality of durum wheat (Triticum turgidum L. subsp.durum (Desf.)van Slageren) in Tunisia.Hence, screening of host plant resistance against these pathogens was the main objective of this study.A total of nine commercial Tunisian durum wheat cultivars were evaluated to STB, TS, YR and LR diseases at adult plant stage over four cropping seasons.The cvs.Karim, Razzak, Om Rabiaa, Khiar, and Maali were vulnerable to STB disease and classified as susceptible to highly susceptible (DS > 60%).While the recent cvs.Nasr, Salim, Monastir and INRAT100 were considered moderately resistant (20% < DS < 40%).Against TS, all cultivars were found to be moderately susceptible to highly susceptible (DS > 40%), except 'Khiar' which exhibit moderately resistant reaction.To YR disease, 'Khiar', 'Nasr', 'Salim', and 'Monastir' were moderately resistant, 'Karim', 'Razzak', 'Om Rabiaa', and 'INRAT100' were moderately susceptible (40% < DS < 60%), while 'Maali' had moderately susceptible to susceptible reaction (40% < DS < 80%).For LR, the cultivars were found within the range of moderately resistant to moderately susceptible (20% < DS < 60%), except 'Nasr was resistant to moderately resistant (DS < 40%).None of the cultivars were resistant to one or more diseases.'Karim' and 'Maali' were found as the more susceptible and 'Nassr' as the less susceptible to the four diseases.Results from this study provide valuable information that helps farmers in selecting the right wheat cultivars from the existing germplasm and for wheat breeders to enhance disease resistance in the future crosses.