General and Specific Combining Ability of F1-Hybrid Sweet Sorghum in Thailand.

General and Specific Combining Ability of F₁-Hybrid

Sweet Sorghum in Thailand

Darika Bunphan^a, Prasit Jaisil^a*, Jirawat Sanitchon^a, Joseph E. Knoll^b and William F. Anderson^b

^a Plant Breeding Research Center for Sustainable Agriculture and Department of Plant Science and Agricultural Resources, Faculty of Agriculture, Khon Kaen University, Khon Kaen 40002, Thailand

^b USDA/ARS Crop Genetics and Breeding Unit, 115 Coastal Way, Tifton GA 31793, USA

*Corresponding author. Tel: +66 89 4165911; Fax: + 66-43 364 636

Email address: pjaisil@gmail.com

ABSTRACT

Sweet sorghum (Sorghum bicolor (L.) Moench) is a promising biofuel crop that accumulates fermentable sugar in the stalk and can be directly fermented as bioethanol. Currently, most of sweet sorghum cultivars are pure lines. However, developing high-yielding hybrids has many advantages. To date there is little information concerning inheritance of important traits suited for hybrid improvement in Thailand or other tropical environments. General (GCA) and specific (SCA) combining abilities where determined from fifteen hybrids generated by crossing five male-sterile A lines with three pollen parents (KKU40, BJ248 and Theis). The hybrids were evaluated in 2013 at Field Crops Research Station at Khon Kaen University, Khon Kaen (KKU) and the National Corn and Sorghum Research Center, Nakhon Ratchasima (NCSRC). A randomized complete block design with three replications was used at each site. GCA effects for Brix of two of the female parents (KKB-53 and KKB-139) were positive and significant. Female parent KKB-48 and male parents BJ248 and KKU40 had positive and significant GCA for biomass and juice yield while Theis was negative for both. Hybrids  showing promising  specific combining ability (SCA) for improvements in Brix were KKA-139 x BJ248, KKA-14 x Theis and KKA-53 x BJ248. The best performing hybrids for total sugar yield ha^-1 were KKA-14 x KKU40, and KKA-139 x BJ248. The study suggests that specific combining ability is very important for traits such as Brix and biomass yield among crosses of available male sterile female and high producing pollen parents in Thailand and other combinations should be attempted.