Diallel analysis of resistance to Fusarium ear rot in Brazilian popcorn genotypes

Among the ear rot pathogens, species of Fusarium cause significant economic losses to popcorn production. To generate popcorn genotypes resistant to Fusarium ear rot, the combining ability of popcorn lines in diallel crosses were assessed during two cropping years: the first from Mar to Sep 2015 and the second from Sep 2015 to Jan 2016. The traits analyzed were: average ear weight (AEW, kg ha−1); grain yield (GY, kg ha−1); popping expansion (PE, g mL−1), Fusarium incidence on ears (EIFU, %); Fusarium ear rot severity index (FSI, %), percentage of fungal-infected kernels (KIF), and percentage of Fusarium-infected kernels (KIFU). Non-additive genetic effects prevailed in the expression of resistance to Fusarium ear rot and grain yield, while additive effects were the most prominent in the expression of popping expansion. Among 56 hybrids, seven showed outstanding grain yield, desirable popping expansion, and resistance to Fusarium ear rot. The less susceptible hybrids to ear rot produced high grain yield and popping expansion. Two disease-related traits, KIFu and EIFu, allowed to best differentiate among the genotypes.