Inheritance of Northern Corn Leaf Blight Resistance in Advanced Generations of Maize (Zea mays L.)

Abstract

Developing genetically resistant maize varieties to mitigate yield losses would reduce reliance on chemical control measures. This study underlines the substantial genetic variability and heritability of northern corn leaf blight (NCLB) resistance within a recombinant inbred line (RIL) population, highlighting the genetic basis of the trait. ANOVA revealed highly significant genetic variability among families at the 1% level, confirming the presence of sufficient variability for effective selection. The progression from F5 to F6 generations demonstrated the effectiveness of selection, as seen from reduced AUDPC scores in the F6 generation. A genetic gain of -7.74 and a heritability estimate of 48% further validated the success of selection based on lower AUDPC scores. The regression analysis supported by the significant positive correlation (r = 0.65) revealed a significant association between F5 selections and the F6 AUDPC scores, as seen from an R2 value of 0.42 and a moderate predictive slope of 0.52. These associations suggest that while selection is effective in predicting advanced-generation performance, the residual variability points to the need for incorporating additional genetic or environmental factors to improve predictive accuracy. These findings emphasize the predominance of genetic factors in NCLB resistance and the stability of resistance traits across the two generations, offering insights into the genetic control of the trait. By providing a solid foundation for breeding efforts targeting durable resistance, this study contributes to the development of maize varieties with enhanced NCLB resistance and supports sustainable agricultural practices.