Wheat, a major Moroccan staple food crop is largely prone to foliar diseases notably Yellow rust, Leaf rust and Septoria Leaf Blotch (SLB). Moreover, Stem rust is becoming an imminent threat to wheat production, unlikely because of the emergence of new virulent races.
The objective of this study was to assess the level of resistance to major diseases of bread and durum wheats across different agro-ecological areas of Morocco during 2020-2021 season, in order to wisely deploy the available commercial cultivars and hence to avoid a rapid breakdown of resistance to prevalent diseases.
A total of 28 and 21 commercial cultivars of bread wheat and durum wheat respectively have been tested at INRA experimental stations (AllalTazi, Annoceur, Douyet and CRRA Meknès) during 2020 -2021 season.
The most prevalent diseases on bread wheat were SLB, Yellow rust and Stem rust. Allal tazi, CRRA Meknès and, Annoceur and Douyet were ideal environments or hot spots for SLB, Stem rust and Yellow rust screening, respectively.
Bread Wheat cultivars that might be recommended for SLB disease prone areas are Blini, Bandera, Guadalete, Kharouba, Radia, Granota, Zenzibar and Wafia.
Those that exhibited a very good level of resistance to yellow rust across the three locations (Douyet, Annoceur, and CRRA Meknès) and that might be recommended for yellow rust disease prone areas are Mahdia, Fadila, Faiza, Najia, Kharouba, Bandera and Wafia.
The most promising bread wheat cultivars with regards to the resistance to stem rust are Fadila (CI = 5), Mahdia (CI = 10), and Wafia, Tilila, Amal and Aguilal (CI = 30). These six cultivars might be recommended for stem rust prone areas.
It is to remind that Fadila and Mahdia are the best cultivars with regard to their resistance to both stem and yellow rusts, but are not recommended for SLB prone areas, whilst Wafia was the only cultivar that exhibited at the same time a very good level of resistance to SLB and to both yellow and Stem rusts. That is, no single cultivar could be recommended for all environments except Wafia.
Durum wheat exhibited a good level of resistance to SLB and Leaf rust at Allal Tazi and to Yellow rust at Douyet. In contrast Irden and Marouan were highly susceptible to Yellow rust at Annoceur.
The fact that almost all commercial bread wheat cultivars are susceptible to highly so to stem rust paves the way for an urgent implementation of a breeding strategy to breed for resistance to stem rust using for instance Wafia, Fadila and Mahdia as donors of resistance.
Moreover and in order to ensure a long lasting wheat diseases management, cultivars deployment strategies should be implemented at country level but also at regional and global levels. It is then wise to Target Population of Environments (TPE) with regards to the occurrence and severity of diseases notably rusts that are wind born, to wisely deploy wheat mega varieties according to global wind direction.
