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United States Department of Agriculture

Agricultural Research Service

Research Project: Improved Forage and Alternative Use Grasses for the Southern U.S.

Location: Crop Germplasm Research

Title: Induced Chromosome Doubling of Sorghum bicolor x Sorghum propinquum Hybrids

Authors
item Wilson, G -
item Burson, Byron
item Dowling, C -
item Jessup, R -

Submitted to: Southern Pasture and Forage Crop Improvement Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: April 15, 2013
Publication Date: N/A

Technical Abstract: Sorghum bicolor (L.) Moench (2n=2x=20) and S. propinquum (Kunth) Hitchc. (2n=2x=20) have a significantly higher degree of interfertility than S. bicolor and S. halepense (L.) Pers. (2n=4x=40), which occurs rarely and results in largely sterile triploids (2n=3x=30). Interspecific hybridization between S. bicolor and S. propinquum therefore provides an efficient opportunity for both developing perennial sorghum feedstocks and investigating the genetics of rhizomatousness. Chromosome doubling of S. bicolor x S. propinquum hybrids would further provide novel, tetraploid (2n=4x=40) germplasm resources lacking interfertility with diploid S. bicolor due to chromosome imbalance mechanisms and reduced or removed risk of unintentional cross-pollination onto commercial annual sorghum. Because S. propinquum produces fewer and less invasive rhizomes than S. halepense, novel, chromosome-doubled S. bicolor x S. propinquum populations would provide opportunities for selection of sufficient degrees of perenniality combined with minimized risk of invasiveness. Such derived germplasm resources would have value towards breeding perennial forage, biofuel, and grain sorghums with increased suitability for renewable fuel standard mandates and sustainable cropping systems. The objectives of this project were to: 1) produce novel S. bicolor x S. propinquum hybrids, and 2) evaluate colchicine-induced chromosome doubling treatments of F1 S. bicolor x S. propinquum hybrids. Sorghum bicolor x S. propinquum F1 hybrids were successfully produced and subsequently treated with colchicine. Seven hybrids with chromosome-doubled tissue sectors have been identified using flow cytometry. These sectors are currently being propagated, subcloned, and evaluated to produce completely tetraploid genotypes.

Last Modified: 12/21/2014
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