Popping patterns in F2 segregant progenies from popcorn x non-popcorn crosses

The most important commercial feature in popcorn (Zea mays L.) is the expansion of the starch contained in the endosperm; however, little has been studied about the underlying genetic basis of this quantitative trait, for which the development of segregating populations is required. The first step is the selection of the most appropriate contrasting parents for popping capacity to create these populations. The objectives of this study were, 1) to analyze the popping patterns of F2 populations derived from crosses between popcorn x non-popcorn inbred lines to identify the most divergent cross for future molecular analysis in search of alleles-related to popping capacity, and 2) to estimate the number of genes responsible for popping expansion volume based on the tails of segregation. Seven biparental crosses of popcorn x non-popcorn were performed to obtain F2 populations, and those were phenotyped for popping expansion volume. Phenotypes were analyzed by the H test, Lilliefors normality-test, Fisher's coefficient of skewness, and kurtosis level. The number of genes estimation was made with X-2 and (1/4)(n) tests. The popping patterns indicated that popcorn x flint corn was the most divergent cross, with the most symmetrical distribution, and therefore, the best suitable population to be used for molecular analysis. Results indicated the existence of three to five major genes related to popping expansion volume. Transgressive segregation was present in all populations, showing individuals whit a popping expansion volume higher or lower than the parental ones, suggesting that non-popcorn lines contain variation for alleles that promote popping.