Plant's phylogeny tree to identify which of them are closer (genetically) with another plant
In general for plants, before you start trying to make your own phylogeny, you should try to find an existing phylogeny. Phylogenetics is complex, and a lot of people have already done the hard work. You can start by looking at the Angiosperm Phylogeny to figure out which species are most closely related. To make use of the tree you will usually have to look up each species to figure out what order or family it is in.



In this particular case, Sorghum bicolor is a grass, so of course it's going to be closed to Zea, Oryza, Setaria and Brachypodium (all grasses) than any of the others. You can see where it places relative to the other grasses by looking at a grass-specific phylogeny. Because all three are model species, their phylogenetic placement relative to one another is well established. A simple Google image search for [grass model species phylogeny] gives you your answer (from the Setaria genome paper):



This shows you that Sorghum is closest to Zea out of the species you listed.