Submitted to: Annual International Plant & Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: 11/4/2004
Publication Date: 1/14/2005
Citation: Price, H.J., Burson, B.L., Hodnett, G.L., Rooney, W.L. 2005. Wide species hybridization in sorghum [abstract]. Plant and Animal Genome XIII Conference. p. 58.
Technical Abstract: The genus Sorghum has 25 species comprising two lineages: one has 2n = 10 relatively large genome species and polyploid relatives (subgenera Para-sorghum and Stiposorghum); the other has 2n= 20 and 2n= 40 species with smaller genomes (Subgenera Eu-sorghum, Chaetosorghum, Heterosorghum. For the past fifty years, sorghum (Sorghum bicolor [L.] Moench) breeders have utilized exotic germplasm, particularly non-cultivated sorghum races as sources of genes for crop improvement. Species outside the subgenus Eu-sorghum are also potential sources of genes for insect and disease resistance, but these species have not been used because they previously have not been crossed with sorghum. Pollen-pistil imcompatibility is the primary reason why hybrids have not been recovered from crosses of S. bicolor and these wild species. When pollinated, there is a reduction of alien pollen germination and inhibition of pollen tube growth on sorghum stigmas. We have overcome the incompatibility by using a S. bicolor genotype that allows growth of alien Sorghum species pollen tubes. Hybrids have been obtained between S. bicolor (2n= 20) and diverse large chromosome species such as S. angustum (2n= 10) and S. nitidum (2n= 20), and between S. bicolor and S. macrospermum (Chaetosorghum, 2n= 40) that have chromosomes of similar size. Chromosome pairing behavior and fertility of these hybrids is being studied.