Genetic Diversity Study of Sweet Sorghum Relating to Cold Tolerance.

Sweet sorghum (Sorghum bicolor (L.) Moench), a C4 plant, shows great tolerance to warm, dry weather, and most varieties are susceptible to cold temperatures during the early growth stages.�� Cold temperatures affect the germination of the sorghum seed as well and compromise stand establishment of the crop.� Because sorghum tolerates warmer temperatures than corn, the areas useful for biofuel production might be expanded.� Identification of cold tolerant varieties of sweet sorghum might permit further expansion.� Since the growth habit of sorghum allows for the production of a ratoon, or regrowth after a harvest, this leads to the ability for multiple harvests a year.� Close to three times the yield (around 30 Mt ha^-1 of dry biomass) can be produced on the same area of land as compared to switch grass because of the ratoon nature of sorghum.� The purpose of this research is to identify and map molecular markers linked to quantitative trait loci (QTLs) whose allelic variants significantly influence cold tolerance.� Plant tissues used in the DNA extraction were obtained by plants that exhibited the traits for cold tolerance in a field trial, planted in early April, collected early June.� After purification, the 50 samples were amplified through PCR with 20 different Simple Sequence Repeats (SSR) primers.� The gels were scored on a present/not-present system, and analyzed with Populations 1.2.30, and a dendrogram created.�