Combining ability in maize topcrosses for grain yield and oil content [electronic resource].

Includes references.

Eighteen yellow maize (S₅) inbred lines derived from population 59E were top crossed to each of three broad genetic base testers namely Pop 59E, Pop 21 and Pop Fat-3 at Sids Agric. Res. Station, in 1997season. The resultant 54 top crosses along with their parental inbred lines and testers were evaluated in field trials at Sakha and Sids Agric. Res. Stations during 1998 season. Data for grain yield, oil percentage and oil yield were recorded to estimates the combining ability effects, determine the type of gene action and select the most superior lines. Results indicated that highly significant mean squares were obtained for lines, testers and their interaction at both locations and combined data, except the testers for oil percentage at Sakha. The best general combiners among parental lines were L-14. L-16 and L-18 for grain yield, L-7, L-10 and L-18 for oil peroentage and L-7 and L-18 for oil yield at both locations and combined. However, inbred lines L-18 showed the best GCA effects at both locations and combined as well as the highest average performance for the three studied traits in combined data. Moreover, the highest desirable SCA effects were obtained from four topcrosses (L-11 x Pop 59E), (L-7 x Pop 21 ), (L-5 x Pop Fat-3) and (L-8 x Pop Fat-3), which had significantly positive values for grain yield. oil percentage and oil yield at both locations and combined data, except (L-7 x Pop21) for oil percentage at Sids. However, the magnitude of dominance (σ² D) gene effects was more important than additive (σ² A) genetic effects in controlling those traits.

Summary in Arabic.

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