Elucidation of the Genetic Components Influencing Cold Tolerance in Sorghum bicolor

Cold stress  is a major constraint in sorghum (Sorghum bicolor L.)  production in many areas of the world.  Temperatures of 15⁰C and below negatively impact germination and seedling establishment  in the  poorly adapted tropical sorghum.The development of cold tolerant sorghum lines may allow for expansion of  growing regions and may confer many of the benefits of early season planting. The objective of this study is the identification of areas of the sorghum genome that enhances sorghum's tolerance to chilling conditions. To identify these areas,  two strategies will be employed. First, using a population of 220 recombinant inbred lines(RIL), developed from a cross between CT19 (cold-tolerant) and TX430 (cold-sensitive), QTLs associated with early-season performance under both cold and optimal conditions will be identified by composite interval mapping (CIM).  QTLs will be validated using a sweet sorghum population of 210 RILs, derived from a cross between M81-E(cold-susceptible) and ISCV-700(cold-tolerant). Germination, emergence, seedling development,  and survivability were observed in both controlled and field conditions for performance under chilling and optimal conditions. Next, a differential expression study will be conducted using parental lines and four RILs (2 cold-tolerant, 2 cold-susceptible) identified from field and controlled environments. RNA-Seq will be utilized to determine differential expressed regions of sorghum genome. Results will be presented at meeting.