Inheritance of leaf anthracnose resistance in tropical maize germplasm
Rodrigo Rodrigues Matiello and Hellen Christine Prochno
Abstract: This study aimed to investigate the genetic basis of resistance to leaf anthracnose (Colletotrichum graminicola Ces.) in tropical maize. Six families, derived from crosses between resistant lines (L04-2 and L23-1) and susceptible lines (L70-2, L71-1, and L95-1), were evaluated for resistance through two experiments. A split-plot design was used, with family effects assigned to the plots and generations to the subplots. Inoculations were performed at growth stages V6 and V7, followed by three assessments at stages V12, R1, and R3, using a grading scale from 1 to 6. Results showed that additive genetic effects predominantly influenced resistance, accounting for up to 99.4% of the phenotypic variation across the six families. Heterosis estimates were consistently high and negative, reinforcing the ability of resistant lines (L04-2 and L23-1) to pass resistance genes to subsequent generations, leading to reduced disease severity.