Inheritance Study for Popping Expansion in Popcorn vs. Flint Corn Genotypes

Popcorn is a popular snack food with higher economic value compared to field corn varieties of maize (Zea mays L.), but displays less favorable agronomic performance and greater susceptibility to diseases. The objective of the present work was to study the mode of inheritance of popping expansion (PE) from three different crosses of popcorn x flint corn with a classical model and a mixed model using inbred lines derived from tropical germplasm. The study will investigate if PE is encoded by one or two major genes, a few genes with large effect, or multiple genes of small effect. Four generations (P-1 and P-2, F-1, F-2, BC1-Popcorn and BC1-Flint) from each cross were evaluated in field experiments in the main growing season of 2013/2014, in two environments. A randomized complete block design was used, with a nested split-plot arrangement of treatments with four replicates. Means of the four generations were determined for PE. A weighted least squares analysis of variance based on the generation means method was used to perform joint scaling tests on the data from each generation. Maximum likelihood estimators were used to test the effect of major genes and/or the presence of polygenic loci affecting the trait. Although inheritance studies with plot means can be used to estimate genetic effects, the effect numbers can be overestimated. In the current study, PE in popcorn vs. flint crosses was controlled by a major additive gene in conjunction with polygenic modifiers acting in both additive and dominant fashions.