In the past years, few grain sorghum varieties with limited yield potential have been developed and grown in Korea. Hybrids tend to be more productive and resistive to unfavorable environmental conditions than pure line varieties. However, no hybrid cultivars are available and never have been planted for grain sorghum in Korea. The main aims of this study were to (i) verify if US x Korean and US x US hybrids increase grain yield in Korea; (ii) assess the performance of waxy hybrids in Korea and the US; (iii) estimate general combining ability and specific combining ability for the lines studied; and (iv) identify superior lines and hybrids for future use in breeding. Two distinct sets of waxy-endosperm sorghum hybrids derived from Korean landraces and US lines (Texas A&M University) were tested in the US and Korea. Compared to the parental lines, hybrids derived from US lines and Korean landraces showed yield increase that ranged from 2% to 127%. Hybrids created from US lines showed higher heterosis than US x Korean hybrids. Hybrid vigor was observed in the US and Korea, but shifts in ranks of hybrid performance occurred. The results indicate that it is feasible to develop grain sorghum hybrids adapted to Korean conditions only if delibrate selections take place in Korea. A combination of Korean and US sources could provide an acceptable germplasm base for developing Korean landrace based sorghum hybrids.

The sorghum (Sorghum bicolor (L.) Moench) variety ‘Sodamchal’ was developed and registered by Department of Sothern Area Crop Science, National Institute of Crop Science (NICS) in 2013. This variety was developed from the cross between ‘Hwanggeumchal’ with brown grain and ’Jungmo4001’ with semi-dwarf trait. ‘Sodamchal’ is the first semi-dwarf stature with waxy endosperm ever developed in Korea. The yield performance of ‘Sodamchal’ was 2.95 MT/ha in local adaptability test for 2 years. It had 91 cm culm length, which was 58 cm shorter than that of ‘Hwanggeumchal’, 26.3 cm panicle length, 22.0 mm thickness of culm, 21.1 g in 1,000 grain weight. It could be reduce the lodging problem and also adapted to mechanized cultivation. ‘Sodamchal’ produces high quantities of polyphenol and radical scavenging activitiy with diphenyl-picrylhydrazyl (DPPH), 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) in pigmented testa. Above all ‘Sodamchal’ is suitable for use as a parental source for the development of improved pollinator parent lines for developing semi-dwarf sorghum with waxy endosperm and antioxidant activity. (Variety registration No. 6244)

‘Nampungchal’ is a Sorghum bicolor L. developed and registered by Department of Sothern area crop science, NICS, RDA in 2012. This variety was developed through pure line breeding method from ‘Namhae’ landrace. ‘Nampungchal’ is a medium maturing variety having 68 days from planting to heading of sorghum in Miryang, Korea. The plant is pigmented (purple), the glumes and grains are red-brown with waxy endosperm. The panicle has less compact shape and the length is 23 cm. The grain yield of ‘Nampungchal’ is about 2.28MT/ha that is higher 9%, when compared with standard variety ‘Hwanggeumchal’. Culm length and width are about 142 cm and 20.2 cm, respectively. It could be reduce the lodging problem by thicker stems and also adapted to mechanized cultivation. ‘Nampungchal’ does produce high quantities of polyphenol and tannin contents with DPPH radical scavenging activity in pigmented testa. The object of this breeding program is improvement for mechanized production with high yield potential, lodging resistant, and responsive to favorable environmental conditions.