Yield performance and preliminary screening of promising bread wheat genotypes for yellow rust and Septoria tritici blotch in Morocco
Bread wheat is the most important staple crop in Morocco. However, the low national production represents less than 50% of national need. Yellow (stripe) rust (Pst) and Septoria tritici blotch (STB) are the most important foliar diseases limiting bread wheat production in Morocco. The objective of this study was to identify effective sources of resistance to Pst and STB and to select candidate lines displaying high yield and resistance traits. A total of 194 bread wheat accessions provided by ICARDA and CIMMYT were evaluated during 2014 for grain yield and reaction to STB and yellow rust. The field trials were carried out at Douyet station, a key Moroccan rainfed location, and were arranged in a replicated complete block design of 3 replicates. For rust, each entry was scored using the modified Cobb scale when the susceptible check had reached 60S. The Saari Prescott scale was used to score STB reactions. The crop season was characterized by early and late drought associated with high temperatures after flowering. About 50% of accessions (99) showed high yields ranging from 1% to 55% above the highest national check, Arrehane (1.86 t/ha). About 48% (93 accessions) were highly resistant to moderately resistant to yellow rust and about 84% (164 accessions) were resistant to moderately resistant to STB. Overall, about 30% (58 lines) of accessions were high yielding with final disease severities ranging from 0-10% for yellow rust and from resistant to moderately resistant for STB. This group incorporates potentially valuable traits beneficial for our wheat breeding program. QUAIU*2/KINDE was the most promising accession with the highest grain yield (2.9 t/ha) combined with foliar disease resistance. Further multi-environment screening and field evaluations are required before recommending accessions for potential release.