Combining Ability for Grain Yield and Popping Expansion in Popcorn (Zea mays everta) Hybrids

The poor yield and popping quality underscore the need for indigenous germplasm improvement. This study aimed to find parents with high general combining ability (GCA) and specific combining ability (SCA) for yield and popping traits. A Line × Tester design was used to hybridize 9 inbred lines and 4 testers, resulting in 36 hybrids. These hybrids were tested in field trials across three agro-ecologies of Nigeria in 2019 and 2020. Three replicates of 5 trials were set up in a Randomized Complete Block Design, and an air popper was used for popping tests. The study showed that crosses differed significantly at ρ≤0.01 for all agronomic traits except ears per plant (EPP) while the line × tester interaction was highly significant for all agronomic traits, except anthesis-silking interval and EPP. Parental lines V7, V9 and M3 had positive and significant GCA effect at ρ≤0.01 for grain yield, while V8, V9, and M3 were positive and significant at ρ≤0.01 for popping volume. Ten Hybrids had positive and significant SCA effect for grain yield and popping volume. Non-additive gene effects were more important in the inheritance of most agronomic studied traits, as evidenced by the line × tester interaction contributing a larger proportion (52 – 86%) to hybrid variance compared to the line effects (10.51 - 44.80%) and tester effects (0.20 to 15.24%).  The study identified parental lines V7, V9, and M3 as good general combiners, whereas M1×V1, M1×V3, M1×V4, M1×V6, M1×V7, M3×V4, M3×V5, M4×V7, M4×V8 and M4×V9 were considered for their superior specific combining ability across various environments, particularly for grain yield and popping volume.