Abstract: The present investigation was carried out at the farm of Rice Research and Training Center Sakha, Kafrelsheikh, Egypt during 2010, 2011 and 2012 seasons to estimate heterosis, gene action, heritability, genetic advance and phenotypic correlation coefficient for some root and grain quality traits in rice by using six populations technique, viz., P1, P2, F1, BC1, BC2 and F2 generations of three rice crosses namely Giza 177xGiza 178 (cross I), Sakha 103xWAB 880 SG 33 (cross II) and Sakha 104xIET 1444 (cross III). Two field experiments were layed out in a randomized complete block design with three replicates. First experiment was flashing water irrigation every 10 days intervals (drought conditions) and second experiment was irrigation every 4 days (normal conditions). The results indicated that highly significant and positive heterosis as a deviation from mid and better- parents were obtained for all root (root length, root volume, number of roots/plant and root/shoot ratio) and grain quality traits (grain length, grain shape, hulling%, milling%, head rice % and amylose content), except all crosses in grain shape and cross II in grain length showed highly significant and negative estimates of heterosis as a deviation from mid-parents. In addition, incomplete dominance to over-dominance was operative for most of the studied traits. Additive gene effect (d) and dominance gene effect (h) were more important in the genetic system for all the studied characters, additivexadditive gene effects (i), additivexdominance (j) and dominancexdominance (l) were involved in the genetic control of all characters with some exceptions. Heritability in broad sense was high in the three studied crosses for all the studied characters, except crosses I and III for root/shoot ratio under normal conditions and cross I for grain length under normal conditions were moderate, the highest value of heritability estimates (95.95) was recorded for root volume in cross III under normal conditions While narrow sense heritability was moderate to low in most of the crosses. High values of predicted genetic advance were estimated for most of the studied crosses. Significant or highly significant positive phenotypic correlation was found between most of all the studied characters in the three studied crosses especially between each of root and grain quality characters with grain yield/plant, except amylose content trait. From the foregoing results, cross III (Sakha 104xIET1444) could be recommended for growing under water deficiency to obtain the highest root and grain quality characters at the same time.