Genetic distance (GD) among six maize inbred lines was determined based on the ISSR marker. A total of 96 amplification bands were produced by ten ISSR primers 35out of them were polymorphic (36.46 % polymorphism). In addition to ISSR analysis the highest similarity level (94.3%) was detected between P2 and p3 which are closely related. However, the highest genetic diversity was between P1 and P4. To study the inheritance of earliness, grain yield and its components in specific three crosses (P2xP3 low diversity, P5xP6 moderate diversity and P1xP4 high diversity), a field trial contained six populations (P1, P2, F1, F2, Bc1 and Bc2) were carried out at Research and Experimental center of the Faculty of Agriculture, Benha University, Egypt. The field study carried out during 2013 and 2014years. Results showed that significant inbred line differences in response to their genetic background, genetic variance within F2 population, desirable heterosis and inbreeding depression were detected for all studied traits in the three crosses.The potence ratio values were higher than unityindicatingover-dominance towards the desirable parent for all studied traits.The additive gene effects (a) and dominance gene effect (d) were significant for most studied traits in the three crosses.The epistatic effect is important as a major contributor in the performance of most studied traits. High heritability values in broad sense were detected for the three crosses except grain yield plant-1 in the first cross. However, heritability in the narrow sense was exhibited to be low. Generally, the variance in F2, mean performance in the F1 and GCV% increased with increasing GD as it shown in cross P1xP4 followed by cross P5xP6 and then by cross P2xP3. This result was crossponding with correlation coefficient (r) between GD and each of varianceof F2 (r= 0.98**) and mean performance of F1 (r= 0.97**) and GCV% (r= 0.79**). Hence, ISSR marker is a powerful,reliable,fast and inexpensivemethod for screening the genetic diversity between maize inbred lines. |
