Heterotic relationships among different local and exotic yellow maize, zea mays l. populations

Devlopment of maize inbred lines is based on the identifcation and utilization of heterotic groups and patterns. A diallel mating design was done, includes different four local and three exotic maize populations, selected as parents to be used in this study. Parental populations and their 21 crosses were evaluated in four environments; i.e., Sakha, Gemmeiza, Nubaria and Mallawy Agriculture Research Stations. The objective of this study was to assess heterotic relationships among different local and exotic populations, and to evaluate combining ability among these populations to determine their potential as source germplasm to enhance grain yield. Results showed that environments effects were significantly different for al studied traitsSK21 and GMY populations produced the highest mean grain yield among the tested populations (7. 26 and 7.05Mg ha-©ö), while, the crosses, having FRYpopulation, had the highest mean grain yield (8.28 Mg ha- ©ö). The largest mid- parent heterosis (23.6%) was observed for FRY population. The mid-parent heterosis, among the crosses, ranged from 7%(SK21¥á DT2) to 29% (GMY¥á FRY), with an average of 16.1% the crosses, GMYX FRY, DT2 x FRY, FRY X POP59, SK21i1JSK21 XPOP59and SK21XFRY, produced the highest mean grain yield among crosses, being 8.73, 8.43, 8.41, 8.34 and 8.24 Mgha-©ö, respectively All these crosses had, at least, one exotic parent. FRY had the lowest parental mean plant height and the second largest significant GCA effect in the downward direction. Cluster analysis was done with mid-parent heterosis for grain yield to identify the diversity among the seven populations. Cluster I included the local populations (SK21, NDT, NY,and GMY),in addition to POP59. Cluster II included DT2 population, while, cluster III included FRY population. The.highest SCA effect was observed among populations in cluster I x populations in clusterIII.Average heterosis for FRY was 23.6 The present study suggested that the two exotic populations; i. e., FRY and POP59 on one side, with SK21 and GMY as the second one, represented a good germplasm source for the developing of new yellow hybrids. It is possible to create two base populations; i.e., A consisted of SK21 x GMY and B included FRY and POP59. Heterosis among A and B new populations would be the optimum for producing high yield hybrids