COMBINING ABILITY EFFECTS FOR SORGHUM EMERGENCE POTENTIAL IN CRUSTED SOILS, COLEOPTILE DIAMETER AND LENGTH, AND KERNEL WEIGHT

Stand establishment of grain sorghum [Sorghum hicolor (L.) Moench] is often a problem in crusted soils common in semi-arid climates. This st udy was conducted to determine the performance and combining abilities of 8 grain sorghum lines for a set of parameters related to emergence potential in crusted soils. The 16 possible F-1 single crosses from t he four restorer male lines Ia9, Ia17, Ks3 and Ks33 and the four male sterile lines Ia33, Ks22, Ks24 and N4692 were evaluated for piston dis placement in an In vitro screening technique, coleoptile diameter and length, and kernel weight. The general combining ability (GCh) effects were highest for the male line Ia9 for piston displacement and coleop tile diameter, the male line Ks33 for coleoptile length, and the femal e line Ia33 for kernel weight. The positive specific combining ability (SCA) effects of K222xIa17 and Ia33xIa9 were the highest for piston d isplacement, while ks24xKs33, Ks24xIa17 and Ia33xIa9 were the highest for coleoptile diameter. Ia33 crossed to Ia17, Ks22xKs33, Ks24xIa17 an d N4692xKs3 gave the highest SCA effects for coleoptile length. SCA ef fects for kernel weight were highest for Ks22xIa17, Ia33xKs24 and N469 2xKs33. Therefore, the lines Ia33 and Ia9 seemed to combine the charac teristics showing positive SCA effects, and to be valuable germplasm s ources for breeding efforts to increase emergence potential in crusted soils. Although Ks33 and Ia33 had the best GCA effects for coleoptile diameter and length, they combined poorly. Male parents had a larger effect on piston displacement and coleoptile diameter, while female pa rents had a larger effect on kernel weight. Breeding programs selectin g and crossing superior males and females for these traits could impro ve emergence of grain sorghum genotypes in crusted soils.