Evaluation of Parents of Elite Single-Cross Maize Hybrids for Their Suitability as Testers

The identification of suitable testers is essential for evaluating newly developed maize inbred lines and selecting promising hybrid combinations. This study assessed the suitability of five parental inbred lines of elite single-cross maize hybrids as testers based on mean testcross performance, general combining ability (GCA), discriminatory ability and consistency in ranking inbred lines. Thirty-four diverse maize inbred lines were crossed with five testers, namely MAI 105, NAI 137, MAI 115, MAI 121 and LM 13, using a line × tester mating design. The resulting 170 testcross hybrids were evaluated for grain yield in two replications. Analysis of variance revealed significant differences among hybrids (P < 0.001), testers (P < 0.05) and line × tester interactions (P < 0.001). The interaction component accounted for 74.26% of the hybrid variation. MAI 121 recorded the highest mean grain yield (129.90 g plant⁻¹) and the largest positive GCA effect (7.262), followed by MAI 115. Although MAI 115 exhibited the greatest numerical variation among testcrosses, Levene's test indicated no significant differences in variance among testers. MAI 105 and NAI 137 showed the highest rank correlations with the pooled reference ranking (0.55 and 0.54, respectively), while MAI 121 exhibited moderate agreement (0.50). Overall, MAI 121 was identified as the most promising tester for selecting high-yielding hybrid combinations within the evaluated genetic materials. Further evaluation across environments and breeding populations is required to establish its broader applicability.