Relationship between causal pathogens for maize ear rots and grain yield in tropical maize in Uganda

Maize ear rots caused by Aspergillus flavus, Fusarium graminearum and Stenocarpella maydis reduce the quality of maize through production of mycotoxins and carcinogenic compounds that are harmful to both humans and animals when consumed. The objective of this study was to determine the relationship between yield and fungal ear rot infections caused by the three fungal pathogens. Tropical inbred lines with varying resistance to A. flavus and both F. graminearum and S .maydis were mated in a North Carolina II Design. The progeny consisting of single crosses, test crosses and their parental inbred lines were thereafter evaluated using single pathogen inoculation. Regression of the three ear rot mean infection scores on mean yield scores across three test locations for both the test and single cross hybrids revealed low yieldvariations in response to fungal ear rot infections. Further, it suggests that maize grain yield cannot be reliably predicted from any of the three ear rot pathogen infection scores. This also suggests that multiple resistance to the three pathogens is inherited independently of yield performance. Resistance to the three ear rots and yield performance should be directly evaluated and improved by separate and independent breeding strategies.