Heterosis and combining ability for some important traits in maize [electronic resource].

Includes reference.

A half diallel cross was made among eight white inbred lines of corn, the resulted crosses and check hybird (S.C. G.10) were tested in both location (Shkha farm, Kafr El-Sheikh governorate and Somosta farm, beni Duif governorate). The aim of this study was carried out to estimate the heterotic effects, general and specific combining ability (GCA and SCA) and their interaction with locations. The studied traits were silking and tasseling dates, plant and ear heights, leaf area of ear, no. of row/ear, no. of kernels/row, 100-kernel weight, shiling persentage and grain yield/plant. The obtained results could be summarized as follows: Location mean squares were significant for all traits except for ear height and number of rows/ ear. Genotypes mean squares were significant for all traits. Significant genotypes x location mean squares were obtained for all traits except shelling percentage. Significant parents mean squares were obtained for all traits. Significant interaction mean squares between parental inbred lines and location were detected for all traits except plant height and shelling percentage. For grain yield/plant, the parental inbred lines P5, P2 and P7 had the highest grain yield/plant, With the exception of inbred lines PI and P6, all inbred lines gave the same g :,-Ad/plant. These inbred lines exhibited high mean values for two or more of the traits contributing to grain yield. However, the parental inbred lines P1 and P6 gave the lowest ones for this trait. For grain yield/plant, fifteen parental combinations had significant superiority over check hybrid S.C. GAO. Fifteen hybrids surpassed the check variety by 16.39 to 75.35 % over the two locations. Also, the best hetcrotic effects were obtained for the crosses P5xP7(75.35), Pi xP3(42,21), xps(38,05), Pi xP8(28,76), P3xP4(32.23), P3)4’43515), P3xP7(31.05), P4xP7(30.44) and p7xp8(33.42). The mean squares associated with general combining ability (GCA) and specific combining ability (SCA) were significant for all the studied traits. GCA/SCA ratio was estimated, it was found that all traits except ear height, number of rows/ear, shelling percentage and 100-kernel weight exhibited low GCA/SCA ratios of less than unity. On the other hand, high GCA/SCA ratio, which exceeded the unity, was obtained for the exceptional traits. The mean squares of interaction between location and both types of combining ability were significant for all traits except shelling - zrcentage. The parental inbred line P1 exhibited significant negative k, effects for tasseling. The inbred line P2 showed significant negative k, effects for plant height. The parental inbred line P3 showed significant negative g, effects for silking date and plant height and ranked the third best-inbred line for both traits. The parental inbred line P5 seemed to be the best combiner for plant height and 100-kernel weight. Also, it showed significant desirable k; effects for ear height and grain yield/plant and ranked the second best inbred line for both traits.

Summary in Arabic.

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