Twenty one new yellow inbred lines from S₅ of maize were top crossed with two inbred lines Sk-73 and Sk-6241 as testers at Sakha Agriculture Research Station in 2004 growing season. The fourty two single crosses and two commercial hybrids SC155 and SC pioneer 3084 were evaluated in summer 2005 at Sakha and Mallawi Research Stations. The data were taken on silking date (days), plant height (cm), ear length (cm) and grain  yield (ard/fed.).The results of the present study combined over two locations could be summarized as follows: Mean squares for testers and lines were significant over the two locations for all traits except plant height for testers. Significant differences were also, detected of lines x testers interaction for all the studied traits except plant height. Additive genetic variances played an important role in the inheritance for grain yield and silking date while the non-additive genetic variances played an important role in the inheritance of plant height and ear length. The magnitude of the interaction between SCA with location was higher than of GCA x location for grain yield and plant height. The new inbred lines Sk-L1, Sk-L17, Sk-L20 and Sk-L21 exhibited the highest positive and significant GCA effects for grain yield and ear length . while, the new inbred lines Sk-L1, Sk-L2, Sk-L3, Sk-L4, Sk-L16 and Sk-L20 had the highest negative and significant GCA effects for number of days to 50% silking (earliness). Ten single crosses  (Sk-73 x Sk-L20), (Sk-73 x Sk-L21), (Sk-6241 x Sk-L6), (Sk-6241 x Sk-L12),  (Sk-6241 x Sk L-15), (Sk-6241 x SkL-16),(Sk-6241 x Sk-L17), (Sk-6241 x Sk-L18), (Sk-6241 x Sk-L20) and (Sk-6241 x Sk-L21) were significantly increased than the commercial SC 3084 (27 ard/fed.) and higher than commercial SC155 (30.9 ard/fed.) but not significantly for grain yield. Meanwhile, five single crosses (Sk-6241 x Sk-L4), (Sk-6241 x Sk-L7), (Sk-6241 x Sk-L16), (Sk-6241 x L19) and (Sk-6241 x Sk-L20) were significantly negative for number of days to silking toward earliness. These single crosses would be prospective and more efficient to be used in maize breeding programs for improving grain yield and earliness.