Combining ability , some genetic parameters and heterosis in maize by using(line × Tester) crossing


This experiment was carried out at the field in the Tway west City of Ramadi. Eight inbred lines of maize ware used in this study using (line × tester) analysis in spring season of 2012, to produce fifteen F1 crosses .The parents and crosses were sowing in autumn season of 2012 using (R.C.B.D) with three replications to determine general and specific combining ability effects, estimate some genetic parameters and heterosis.Statistical analysis revealed highlySignificant differences increases for all traits. the result were showecd that the tester ( S5) gave the highest positivet gca for all traits.the Line(Zm19R) gave the highest positivet gca for Leaf area, no.grains / rows and plant yield . the cross (Zm19R × S2) gave the highest positivet Sca for Leaf are and grain yield per plant(368.33)and (55.45) to succession. The value of specificcombining ability variance were more than the general combining ability variance for all traits indicating the importance of non – additive gene action. This reflects the reduction of the values for all characters and this reflects the reduction of the values of the narrow sence heritability for all characters and the estimates of the average of dominance were exceeded one for all characters except the no. grains/rows . the cross (Zm7R × S5) gave highly positive hybrid vigor for Leaf area,AGR,CGR,300 grain weightand plant yield(%49.65 and %133.86 and %133.88 and %44.20 and %211.24)respectively. the results indicate that wecan used some inbred Lines could be used in a breeding program to develop new versions of high yield per plant and SCA to produce better grain yield hybrids and most studied traits were under dominance and over dominance gene action.