A Study on combining ability and heterosis were conducted on 12 F₁ hybrids along with seven rice genotypes field experiment was carried out at the Farm of Rice Research and TrainingCenter, Sakha, Kafr El-sheikh, Egypt using to line x tester mating design, during 2012 and 2013 seasons. The objectives of this investigation was aimed to know the pattern of inheritance of some grain yield and its component and grain quality characters in rice for selecting superior genotypes. The present investigation. The Line, GZ 8455-6-8-3-1was earlier and shorter than other linens, its estimated values of days to complete heading and plant height were (99 days and 96.24 cm), respectively. Among the linens, GZ 8372-13-1-3-1 followed by GZ 8455-6-8-3-1. were found to be longest panicle length, highest number of  panicle per plant, lowest sterility %, heaviest 100 grain weight and highest grain yield per plant. On the other hand, Sakha 103 and Sakha 102 were found to be the earliest Testers. Moreover, Sakha 101 was found to be the shortest tester. In addition GZ 8455-6-8-3-1 x Sakha 102 followed by GZ 8455-6-8-3-1 x Sakha 104 were the earliest rice cross combinations. While, the shortest plant height (98.14 cm) was lasted from GZ 8455-6-8-3-1 x Sakha 102.             Analysis of variance revealed significant differences among genotypes, crosses, lines, testers and line x tester interactions for yield and its component and grain quality characters. Both GCA and SCA Variances were highly significant for all the studied characters indicating the predominance of additive and non additive gene action in the inheritance of all characters. The estimated ratio of GCA/SCA was lower than unity for all the studied traits except days to complete heading trait, indicating the importance of non-additive gene action in the inheritance of all traits, except days to complete heading trait, which was fond to be controlled by additive gene action. The highest heterobeltiosis were obtained for cross GZ8951-9-7-1-3 x Sakha 103 followed by GZ 8951-9-7-1-3 x Sakha 102, GZ 8951-9-7-1-3 x Sakha 101 and GZ 8951-9-7-1-3 x Sakha 102 rice crosses for number of panicles/plant and head rice %, respectively. The proportional contribution of testers was observed to be higher than that of the interactions of line x tester that revealed the highest estimates of GCA variance.          The cross combinations GZ 8951-9-7-1-3 x Sakha 101, GZ 8455-6-8-3-1 x Sakha 104, GZ 8455-6-8-3-1 x Sakha 101, GZ 8951-9-7-1-3 x Sakha 103, GZ 8372-13-1-3-1 x Sakha 104 and GZ 8372-13-1-3-1 x Sakha 101 were observed to be good specific cross combinations for grain yield and grain quality characters to their highly significant SCA and heterobeltiosis effects. High broad sense heritability (96.23%) was recorded for days to complete heading. While high narrow sense heritability was recorded for number of filled grains / panicle (50.14%). Highest estimates of expected genetic advance were observed for gel consistency and 100 grain weight. Highly significant and positive estimates of phenotypic correlation coefficient were found between grain yield and each of hulling %, milling %, head rice %, grain elongation, gel consistency and gelatinization temperature.