Evaluation of public sweet sorghum A-lines for use in hybrid production

Authors: Pedersen, Jeffrey; Sattler, Scott; Anderson, William - Bill

Submitted to: BioEnergy Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/14/2012
Publication Date: 3/1/2013
Citation: Pedersen, J.F., Sattler, S.E., Anderson, W.F. 2012. Evaluation of public sweet sorghum A-lines for use in hybrid production. BioEnergy Research. 6: 91-102. DOI:10.1007/s12155-012-9231-1

Interpretive Summary: Sweet sorghum is receiving substantial attention as a bioenergy crop throughout the world. However, very large amounts of seed will be required before sweet sorghum can be deployed and utilized on a commercial scale. In order to generate such large quantities of seed, the commercial seed industry will need to produce hybrid varieties on dwarf seed-parent lines with high seed yields and which are amenable to mechanical harvest. Because several years are required to develop new seed parent lines, immediate efforts towards production of sweet sorghum hybrids will necessarily use existing dwarf seed-parent lines. A set of 6 public sweet sorghum seed-parent lines (Dwarf Kansas Sourless, KS9, N36, N38, N39, and N4692) were crossed with a set of 6 public sweet sorghum cultivars (Brawley, Kansas Collier, Dale, Sugar Drip, Waconia, and Wray) to produce experimental hybrids. Grain, fiber, and sugar yields were determined, and ethanol yields estimated using standard conversion formulas. One seed-parent line, N38, was inferior. Average total ethanol yields from hybrids made on the other seed-parent were not significantly different, suggesting that any of those five seed-parent could be useful seed-parents. With the exception of grain yield, cultivars used as pollen parents were among the highest performing entries for all traits. For all traits directly contributing to total ethanol yield (grain yield, juice yield, % soluble solids, sugar yield, fiber yield), hybrids were also among the highest performing entries. Results of this study demonstrate that hybrid sweet sorghum with performance criteria equivalent to existing sweet sorghum cultivars can be produced on existing sweet sorghum seed-parent lines. Identification of specific seed-parent x pollen parent lines with characteristics best suited for particular growing regions and end-user needs will be critical for commercial hybrid development.

Technical Abstract: A fundamental need for commercialization of sweet sorghum [Sorghum bicolor (L.) Moench] as a bioenergy crop is an adequate seed supply, which will require development of hybrid varieties using dwarf seed-parent lines. A set of 6 public sweet sorghum A-lines (Dwarf Kansas Sourless, KS9, N36, N38, N39, and N4692) were crossed with a set of 6 public sweet sorghum cultivars (Brawley, Kansas Collier, Dale, Sugar Drip, Waconia, and Wray), grain, fiber, and sugar yields determined, and conversion formulas applied to estimate ethanol yields. Hybrids were grown in fields in at Ithaca, NE in 1983-1984 fertilized with 112 kg ha-1 N. In terms of component yields and overall ethanol yields, one A-line, N38, was inferior. Average total ethanol yields from hybrids made on the other A-lines were not significantly different, suggesting that any of those five A-lines could be useful seed-parents. With the exception of grain yield, cultivars used as pollen parents were among the highest performing entries for all traits. For all traits directly contributing to total ethanol yield (grain yield, juice yield, % soluble solids, sugar yield, fiber yield), hybrids were also among the highest performing entries. Results of this study demonstrate that hybrid sweet sorghum with performance criteria equivalent to existing sweet sorghum cultivars can be produced on the sweet sorghum seed parent lines A-Dwarf Kansas Sourless, A-KS9, A-N36, A-N39 and A-N4692. Identification of specific seed-parent x pollen parent lines with characteristics best suited for particular growing regions and end-user needs will be critical for commercial hybrid development.