Determination of Combining Ability and Type of Gene Action Using Half-Diallel Cross Among Seven S6 White Maize Inbred Lines

Abstract

Seven S6 white maize inbred lines were derived from selfing of S4 inbred lines of two populations; three way cross-324 and Giza-2 were used as parents of a 7 x 7 half-diallel cross and were obtained on 21 F1 crosses. These 7 S6 inbred lines and their 21 F1 crosses along with the 2 checks i.e., SC-128 and SC-129 were evaluated at Experimental Farm, Faculty of Agriculture, Al-Azhar University, Assiut Branch in 2021. Highly significant differences were detected among genotypes, parents, crosses, parents vs. crosses, general and specific combining abilities for all traits. σ 2 GCA/σ 2 SCA was less than the unity for all traits. The 4 crosses; P4 x P7, P5 x P6, P5 x P7 and P6 x P7 possessed desirable significant positive heterotic effects for increasing grain yield/plant relative to the checks SC-128 and SC-129, and among them the 3 crosses; P5 x P6, P5 x P7 and P6 x P7, also possessed significant negative desirable standard heterotic effects for tasseling and silking earliness relative to both the checks. The 2 parents; P6 and P7, which derived from Giza-2 population could be considered as good general combiners for improving maize genotypes for earliness and high yielding ability. The 9 crosses; P1 × P2, P1 × P4, P1 × P5, P2 × P6, P3 × P4, P3 × P7, P5 × P6, P5 × P7 and P6 × P7 possessed significant positive desirable SCA effects for high yielding ability, as well as significant negative desirable SCA effects for earliness. The dominance was in over dominance range for all the studied traits, where the average degree of dominance was more than one.

Superiority and Combining Ability for Grain Yield and Agronomic Traits of Maize (Zea mays L.)

“…Abd Results showed that variances of GCA and SCA were significant and highly significant for all studied traits except for SCA of EHT, indicating that additive and non-additive gene effects were important in the inheritance of most studied traits. Our results are relevant to those obtained by Bisen et al, (2020) and Abd EL-Zaher et al, (2021) for DTS and PHT, Onejeme et al, (2020) and Ramadan et al, (2022) for DTS, PHT and GY, Abd EL-Azeem et al, (2021) for DTS, PHT, Epos% and GY, Patil et al, (2021) for DTS and GY and Abdulla et al, (2022) for DTS and PHT. The ratio of GCA/SCA was more than unity for all studied traits except GY trait, indicating that the additive gene effects were more important and played major role in the inheritance of all studied traits except for GY trait.…”