Genetic Diversity and Responses of Some Selected Yellow Maize Genotypes to Stem Borer (Sesamia calamistis Hampson) Infestation

Abstract

Aims: Identification of promising resistant parents against stem borer infestation for the development of high yielding maize hybrids.
 Study Design: Ten yellow maize genotypes selected for yield potential and durable level of tolerance to stem borer infestation were used in this study. A stem borer resistant yellow maize variety was crossed with nine stem borer (not necessarily resistant) maize varieties in a top-cross mating design.
 Place and Duration of Study: The study was conducted in 2017 and 2018 at the Institute of Agricultural Research and Training, OAU, Ibadan, Nigeria.
 Methodology: The resulting nine F1 hybrids along with the ten parents were evaluated under irrigation using a Randomized Complete Block Design (RCBD) with three replications in a stem borer endemic area. Data collected were subjected to combined analysis of variance (ANOVA), principal component analysis (PCA) and hierarchical clustering analyses.
 Results: Results obtained showed significant differences for year and genotype, as well as their interaction for some traits measured. Maize varieties were delineated into three groups. The first two PCA with Eigen values greater than 1.0 accounted for 73.0% of the variation; where PC1 was responsible for 52.5% of the variation and was associated with percentage stem borer infestation, leaf damage, plant aspect, stem tunneling ratio and dead heart. PC2 accounted for 20.5% and associated with only grain yield (GY). Also, maize hybrids had higher GY and better resistance to stem borer than their parents by 24.3% and -14.3%, respectively. BR9928-DMR-SR-Y was identified as resistant to stem borer with high GY in hybrid combinations. Positive and significant correlation was obtained among infestation parameters.
 Conclusion: Genes from promising donor parents may be introgressed into other desirable maize germplasm for the development of stem borer resistant maize hybrids.