Six inbred lines (1-S10, 2-Zn12, 3-Sy24, 4-Zm17, 5-O18, 6-Mgw7) of maize were crossed in half diallel to produce 15 single cross in Field Crops Research–Abu Ghraib in fall season 2014. Seeds of genotypes (6 lines +15 single cross) have been planted in field of a farmer in Abu-Ghraib, using randomized complete block design (R.C.B.D), with three replicates in fall season of 2015, to evaluate the performance of these lines and hybrids and to estimate genetic diversity among 6 lines and 15 single cross by using Mahalanobis D2 statistic for 10 morphological traits Viz. days to silking, plant height, ear height, leaves number, leaf area, ear number per plant, ear length, rows number per ear, 250-kernel weight and yield kernel per plant.
Statistical analysis showed significant variation among maize genotypes for all studied traits. The six inbred lines were grouped into three different clusters by using cluster analysis. The cluster I contained the highest number of lines 1, 2, 5 cluster II contained towlines 3 and 4 and cluster III contained one line 6. The highest mean values for all traits, which, in clouding grain yield per plant about 146g were observed in cluster III, except ear height with 69.83 cm, and the lowest mean value for days to 50% silking as 61.50 day were found in cluster II. The inter-cluster distances were larger than intra-cluster distances, suggesting wider genetic diversity among the lines of different groups. The highest inter-cluster distance was observed between cluster I and cluster III with 6.49, and lowest between cluster II and cluster III with 3.85. The highest intra-cluster distance was noticed in cluster I as 3.3%. and lowest for cluster III. Fifteen hybrids were grouped into six clusters, The cluster I contained the highest number of hybrids 1, 2, 3, 4, 5, 6, 9, 10 and 11 cluster II, III, V, and VI contained one hybrid for each one 7, 8, 13 and 15 respectively, while cluster IV contained tow hybrids 21 and 14. The highest mean values for plant height, leaves number per plant, leaf area, ear length, rows number per ear by17.34, 250-kemel weight with 65.00 g and grain yield per plant as 174.17 g were observed in the cluster IV.
The mean of ear height with 82.33cm was the highest in cluster II and the mean highest for number of ears per plant about 1.30 was the highest in cluster VI. The lowest mean value for days to silking with 58.00 day was found in cluster V and cluster VI. The inter cluster distances were larger than intra-cluster distances, suggesting wider genetic diversity among the hybrids of different groups. The highest inter-cluster distance was observed between cluster IV and cluster VI with 7.03, and the Lowest between cluster I and cluster II about 3.54. The highest intra-cluster distance was noticed in cluster I abut 3.76.