COMBINING ABILITY OF NEW YELLOW MAIZE INBRED LINES USING LINE x TESTER MATING DESIGN

General (GCA) and specific (SCA) combining ability were estimated in a lines x testers crossing program comprising 36 crosses of maize produced by crossing eighteen yellow inbred lines with two testers in 2014 season. The resulting 36 test crosses along with the two check hybrids SC.162 and TWC353 were evaluated for six traits, i.e. days to 50% silking, plant height,ear height, ear length, ear diameter and grain yield/ha at Sakha and Ismailia Agric. Res. Stations in 2015 grown season. Significant differences were obtained among crosses and their partitioning into lines, testers and line x
testers for all studied traits, except testers for ear diameter and line x tester for number of days to 50% silking, plant height, ear length, ear diameter and grain yield. The additive gene action was more important than non-additive
gene action for days to 50% silking and grain yield, while the non-additive gene action was more important for other traits. The best inbred lines for GCA effects were Sk-5001/32 and Sk-5001/33 for days to 50% silking, Sk-5001/36
and Sk-5001/38 for plant and ear height, Sk-5001/21, Sk-5001/29 and Sk-5001/36 for ear length, Sk-5001/24, Sk-5001/29 and Sk-5001/36for ear diameter and Sk-5001/29, Sk-5001/30 and Sk-5001/36 for grain yield. Whereas, the line GZ-666 was the best tester for GCA effects for number of days to 50% silking and plant and ear height, while the single cross 162 was the best tester for ear length, ear diameter and grain yield. Two crosses (Sk-5001/25 x GZ-666 and sk-001/33 x SC 162) were found to be the best for SCA effects for grain yield. Most single crosses and all three way crosses
were significantly outyielding both checks SC162 and TWC353, respectively.