Evaluation of wheat genotypes for field resistance to wheat blast caused by Magnaporthe oryzae pathotype Triticum (MoT) and correlation between yield loss and disease incidence in the Brazilian Cerrado

Abstract

Wheat blast caused by Magnaporthe oryzae pathotype Triticum (MoT) has become an important fungal disease on wheat and is now present in most of the important wheat-producing tropical regions of the world. This study evaluated head blast incidence on the spikes of 281 hexaploid wheat genotypes and two Triticum durum cultivars across three years (2011–2013) in the Cerrado Biome in the Brazilian Midwest, a hotspot area and where the highest disease levels have been recorded. Forty eight host lines exhibiting moderate to high resistance to the disease included synthetic hexaploid wheat genotypes (SHW) and derivatives (17), breeding lines (16), landraces (2), and cultivars (13). Thirty early genotypes were identified to have head blast incidence levels similar to the moderately resistant cultivar BR 18. In addition, seven medium maturing genotypes and ten late maturing genotypes had average disease incidence scores on spikes below 35%. These were grouped separately from all other materials. This study also indicated a strong correlation between head blast incidence and yield loss, indicating that incidence could be an appropriate selection parameter in breeding programs targeting blast resistance.