Development of Novel Perennial Sorghum Gemplasm: Induced Polyploidization And Hybridization of S. Bicolor X S. Propinquum

Plant polyploidization can provide valuable, novel phenotypes. In Sorghum, induced polyploidization is possible and relatively inexpensive. However, efficiency remains low and a consensus “best” method has yet to be determined. Some Sorghum species provide a unique opportunity to develop perennial cropping systems due to their interspecific hybridization compatibility and phenotypic plasticity from annual to perennial life cycle. Due to their relatively close taxonomic relationship, Sorghum bicolor (L.) Moench x S. propinquum (Kunth) Hitchc. offer both valuable insights between annuals and perennials, as well as hybridization opportunities for the introgression of perenniality into a major cereal crop. Hybridization between these species also has potential to introgress other desirable alleles that have been lost through the domestication of S. bicolor. Our research identified transgressive segregation for height in a Sorghum bicolor x S. propinquum F2 population. Perennial Sorghum hybrids (PSH) were also intermediate for days to maturity and tillering capacity; when compared to both parents. Experimental units overwintered through harsh winter conditions which allowed a stronger selection criterion for overwintering capacity than previous studies. Unfortunately, our novel method for inducing ploidy levels in Sorghum were unsuccessful. Thus, more research is still needed to improve this methodology. This thesis addresses induced polyploidy, wide hybridization, and perenniality in the genus Sorghum with the purpose of developing novel germplasm suitable for perennial cropping systems