Phenology of Tropical Corn Genotypes in Central Iowa.

Biomass production in the Midwestern United States has largely been focused on corn (Zea mays L.)-grain ethanol production and most recently corn stover, lignocellulosic ethanol. Corn production in this region is profitable and productive. Alternatively, tropical corn genotypes have been evaluated mainly for grain production, nevertheless, yields have fallen short of U.S. Corn Belt populations.  Tropical corn has high grain moisture at harvest, later flowering times, and taller plants.  Tropical germplasm for temperate environments are not attractive for high grain yields, but show promising results for biomass potential through taller and more vigorous plants with thick stems and long leaves. The comparison between tropical corn and their adapted strains with a focus on biomass production has not yet been explored under Iowa daylength conditions. Field trails were established at the Sorensen Research Farm in Boone County, IA during the 2014 growing season.  Three genotypes (Tuxpeno, Suwan, and Tuson) were planted at different dates (7 of May, 20 of May and 3 of June) to evaluate photoperiod response.  This study will identify the adaptability of the genotypes by means of studying crop development.  Adapted strains reached  sooner the maximum vegetative development and begun to flowering earlier than tropical ones; furthermore, tropical strains shown taller plants and thick stems suggesting relatively propitious yields at the end of the growing season. The main hypothesis is that tropical genotypes with longer growth cycles having a higher sensitivity to photoperiod than the short ones will result in delayed flowering time and greater biomass yields, especially in northern temperate climates similar to Iowa.