Estimation of some physiological and genetical parameters for yield and its components in maize Zea mays L. by using Line× tester cross

Abstract

Eight inbred lines of corn ABS5, ABS9, ABS27, ZP607, pio-46, H-S, pio-47 and pio-25 were used in this study and given numbers from 1 to 8 respectively.All these lines were subjected to (Line × Tester) hybrid system. ABS5, ABS9 and ABS27 were used as testers, while ZP607, pio-46, H.S, pio-47and pio-25 were used as lines. The lines and the produced hybrids were sown in Al-Dhabdiah region- Anbar governorate during the autumn and spring season of 2012. The experiment was designed as Randomized Complete Block Design (RCBD) with three replicates. The results were recorded on some physiological parameters, yield and its components and harvest index and then were statistically analysed in order to study the average of performance and the effect of General Combining Ability (GCA) and Special Combining (SCA) in addition to estimate some of genetic parameters in the studied characters. The results indicated that there were significant differences in the average of studied characters for parents and their hybrids. The hybrid zp607×ABS27 gave higher hybrid vigour in grain yield (78.88%) comparing with the best parents. The line ABS5 gave significant positive effect of GCA and was superior in the average of plant height,the time to female anthesis, growth rate, number of ears per plants fertility ratio, grain weight per ear and individual plant yield.Whereas, H-S was also superior and desired in GCA and most of the characters. The hybrid zp607×ABS9 had significantly positive effecte in SCA and was superior in the average of its performance of most studied characters (e.g. Grain yield), followed by H-S×ABS5 and pio-25 × ABS9 . The variance component of GCA was less than SCA and the genetic dominance variance was more important than the genetic additive variance and decrease in heritability ratio where was between (4.7-37.68%) in grain yield which leads to increase the dominance degree over one for all studied characters. As a result of this study, these hybrids have the potential to be used as a hybrid cultivars after evaluating them and comparing them with the current hybrid cultivars. The best way to improve these hybrids is the frequent reciprocal selection.