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ARS Home » Southeast Area » Tifton, Georgia » Crop Genetics and Breeding Research » Research » Publications at this Location » Publication #305263
Title: Heterosis and combining ability of F1 hybrid sweet sorghum in Thailand

Author
item BUNPHAN, DARIKA - Khon Kaen University
item JAISIL, PRASIT - Khon Kaen University
item SANITCHON, JIRAWAT - Khon Kaen University
item Knoll, Joseph - Joe
item Anderson, William - Bill

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/1/2014
Publication Date: 12/16/2014
Citation: Bunphan, D., Jaisil, P., Sanitchon, J., Knoll, J.E., Anderson, W.F. 2014. Heterosis and combining ability of F1 hybrid sweet sorghum in Thailand. Crop Science. 55:178-187.

Interpretive Summary: Sweet sorghum (Sorghum bicolor (L.) Moench) is a potential biofuel crop that is well-suited to tropical environments. It is similar to sugarcane (Saccharum officinarum L.) in that it accumulates soluble sugars in its stems, which can be easily converted to ethanol for biofuel; but unlike sugarcane, it is grown from seed and matures in one growing season. It also produces grain that could be used for ethanol or animal feed. Most sweet sorghum cultivars currently being grown are inbred lines, but hybrids could have yield advantages. This experiment was conducted to determine the performance of hybrid sweet sorghum in Thailand. Fifteen hybrids were generated by crossing five female (seed parent) lines with three male (pollen parent) lines. The hybrids, parents, and three inbred checks were evaluated under two environments in 2013: Field Crop Research Station at Khon Kaen University, Khon Kaen (KKU) and National Corn and Sorghum Research Center, Nakhon Rachsima (NCSRC). A randomized complete block design with three replications was used at each site. Sugar yield was positively correlated with juice Brix (% solubles), plant height, stalk diameter, biomass yield, stripped stalk yield, and juice yield, while grain yield was negatively correlated with juice Brix and sugar yield. Mid-parent heterosis is a measurement of how a hybrid performs relative to the average performance of its parents, while high parent heterosis is a measurement of how a hybrid performs relative to its highest performing parent. Positive heterosis for juice Brix was not observed, though five hybrids had negative mid-parent heterosis for this trait. Positive heterosis for biomass yield, juice yield, grain yield, and sugar yield was observed in some hybrids. Combining ability is a measurement of how a hybrid performs in comparison to other hybrids in the same test. Combining ability can be defined as general, measured for all hybrids with a common parent, or specific for only a particular cross. General combining ability (GCA) was observed for most traits, but specific combining ability (SCA) effects were of greater importance. Overall, the hybrids KKA-11 × KKU40, KKA-139 × BJ248, KKA-14 × KKU40, and KKA-53 × Theis had the greatest SCA for sugar yield. Adding calculated ethanol production from both sugar and grain fractions, two of the hybrids in this study (KKA-11 × BJ248 and KKA-139 × BJ248) could produce approximately 5,000 l ha-1 ethanol.

Technical Abstract: Sweet sorghum (Sorghum bicolor (L.) Moench) is a sugar-based biofuel crop that is well-suited to tropical environments. Most sweet sorghum cultivars are open-pollinated, but hybrids could offer yield and seed production advantages. Fifteen hybrids were generated among five female and three male parents. The hybrids, parents, and three inbred checks were evaluated for sugar yield and related traits under two environments in Thailand in 2013: Field Crop Research Station at Khon Kaen University, Khon Kaen (KKU) and National Corn and Sorghum Research Center, Nakhon Rachsima (NCSRC). Theoretical sugar yield was positively correlated with juice Brix, plant height, stalk diameter, biomass yield, stripped stalk yield, and theoretical juice yield. Grain yield was negatively correlated with Brix and theoretical sugar yield. Positive heterosis for juice Brix was not observed, though five hybrids had negative mid-parent heterosis for this trait. Positive heterosis for biomass yield, theoretical juice yield, and grain yield was observed in some hybrids. General combining ability (GCA) was observed for most traits, but specific combining ability (SCA) effects were of greater importance. Overall, the hybrids KKA-11 × BJ248, KKA-11 × KKU40, KKA-139 × BJ248, KKA-14 × KKU40, and KKA-53 × Theis had the greatest SCA for theoretical sugar yield. Producing ethanol from both sugar and grain fractions, two of the hybrids in this study (KKA-11 × BJ248 and KKA-139 × BJ248) could produce approximately 4,600 L ha-1 ethanol in Thailand.