An Analysis of Broomcorn Diversity.

Broomcorn (Sorghum vulgare var. technicum) is a type of sorghum that is commonly used in the broom industry as its panicles being the functional material used for the manufacturing of corn brooms. For ideal broomcorn varieties, the panicle is extended and contains fibers that are 12-24 inches in length and develop outwards from the nodes on top of the peduncle. Seeds are clustered at the ends of the panicles. After harvest the seeds are removed and the panicle fibers are woven into brooms. These fibers provide support from the thicker portion and collect dust on the pedicels at the opposite end of the fibers. Over the past forty years, the University of Illinois has seen improvements in broomcorn from field breeding for desired harvest and broom quality traits. Broom quality traits, including total panicle length, yield per panicle, proportion of panicle with seed, seed color, plant height, and a qualitative measurement of central branch fusion were measured across 55 populations of broomcorn.  Analysis of these traits provided measure of phenotypic diversity.  Genotyping the same populations with single nucleotide polymorphisms (SNPs) allowed for genotypic diversity analysis.  Fixation index was calculated in R and assessed differentiation in genes for the different broomcorn types. A phylogenetic tree, created from the SNPhylo pipeline, looks at evolutionary relationships between the broomcorn populations. The phenotypic and genotypic diversity evaluated in this study will aid breeders in future varietal selection and broomcorn improvement.