Abstract: A container having a port for holding a liquid medium and a reactant that interact to produce a change in gas levels within the container. A removable stopper for insertion into the port creating an airtight seal. A tube extending through the stopper into the container having a distal end for being submerged in the liquid medium for receiving the liquid medium and monitoring a change in the level of the liquid medium within the container. A controller is provided extending through the stopper into the container for setting the liquid medium at a level within the tube, wherein the controller is operable to direct the liquid medium into the tube to a desired level so that a change in gas levels caused by the interaction of the reactant with the liquid medium can be monitored through a change in the level of the liquid medium within the tube.

Abstract: This invention provides a novel means of making maize hybrids and inbreds with expanded ear tip phenotypes for promoting increased seed yield from recessive genetic determinants. This is achieved by making standard inbred×hybrid as well as inbred×inbred crosses followed by selection in the subsequent self-pollinated generations from these plants for expanded ear tip phenotype characteristics to produce new parent inbred lines. Next, the resulting inbreds, having a different pedigree but possessing the recessive expanded ear tip genetic determinants, are crossed to cause the expanded ear tip trait to express as a homozygous recessive trait in an otherwise primarily heterozygous hybrid.