Estimation of Combining Ability and Heterosis for Some Maize Inbred Lines and Its Single Crosses

Abstract

Two field experiments were conducted out during 2012 and 2013 seasons to estimate combining ability, heterosis for six inbred lines (Three American inbreds: P97, B73and Oh.43 and three Egyptian inbred lines: R39, Inb.1021 and Inb.1004) and its F1 crosses. The most important results obtained from this investigation can be summarized as follows:  The differences among means of parental inbreds and also among means of crosses were significant or highly significant for all studied traits.  Mean squares of crosses were highly significant for all studied traits, indicating wide range of genetic variability among the studied crosses and this is primary requirement for further computation.  Both general and specific combining abilities mean squares were found to be highly significant for all studied traits.  GCA/SCA variances ratios were found to be lower than unity for six traits i.e. time to tassel emergency, time to silk emergency, number of rows/ear, number of kernels/row, grain yield/plant and shelling percentage and higher than unity for plant height and 100-Kernel weigh.  Significant positive general combining ability (GCA) effects were found for most studied traits. The best combiners were P2 (P79) and P4 (Inb.1021) for earliness traits; P5 (Inb.1004) and P6 (Oh.43) for plant height; P5 (Inb.1004) for number of rows/ear; P1 (R39) for number of grains/row; P2 (P97), P3 (B73) and P4 (Inb.1021) for 100-grain weight; P1 (R39) for grain yield/plant; P1 (R39) and P2 (P97) for shelling percentage.  Significant positive specific combining ability (SCA) effects were found for most studied traits. The best cross combinations P3×P4 for number of rows/ear; P1×P5 for number of grains/row; P1×P3, P1×P6, P2×P3, P2×P5, P3×P5 and P4×P6 for 100-Grain weight; P1×P2, P1×P5, P2×P5, P3×P6 and P4×P5 for grain yield/plant; P1×P5, P3×P6 and P4×P5 for shelling percentage.  Results showed significant or highly significant heterosis over mid-parents and better parents for all studied traits. The best crosses over mid and better parents were (P1×P5) for number of rows/ear; (P1×P6) for number of grains/row; (P2×P5) for100-grain weight;(P1×P6)for grain yield and (P1×P4) for shelling percentage.  The study recommends using inbred line P3 (B73) and crosses P1×P2, P1×P3 and P3×P6 in breeding program of maize to improve the yield and its components where they recorded the highest value of the grain yield/plant and gave a better combining ability.

Combining ability for some inbred lines in half-diallel crosses of maize under two different locations conditions

“…303) showed significant or highly significant positive (g^i), as the combined data over two locations, indicating that these inbred lines could be considered as the best combiners for increasing grain yield. Similar results were reported by Soliman and Osman (2006), Sultan et al (2012 and, Attia et al (2013 and2015) and Abdel-Moneam et al (2014a, b, c).…”

Combining Ability and Superiority for Yield and Some Related Traits in Half-Diallel Crosses of Nine New Yellow Maize Inbred Lines Under Two Locations

“…It is interest to note that the previous crosses shord at least one of good general combiner parent. Similar results were reported by other authors such as, Sultan et al (2012 and, Attia et al (2013 and2015) and Abdel-Moneam et al (2014,a, b and c).…”

“…508), P 7 (Gm.518) and P 8 (Gm. 520) at Gemmeiza location;three parental inbred lines namely : P 1 (Gm.500) and P 2 (Gm.505) and P 4 (Gm.508) at Sids location, and four parental inbred lines namely: P 2 (Gm.505), P 4 (Gm.508), P 7 (Gm.518) and P 8 (Gm.520)at combined data over both locations, showed positive significant or highly significant (g^i), indicating that these inbred lines could be considered as the best combiners for increasing grain yield, as reported by Soliman and Osman (2006), Sultan et al (2012 and, Attia et al (2013 and2015) and Abdel-Moneam et al (2014,a, b and c).…”

Diallel Cross Analysis for some White Maize Inbred Lines under Two Nitrogen Levels

“…The GCA/SCA ratio was less than unity for all the studied traits under both nitrogen levels and their combined data, except days to 50% silking under N1 level (90 kg N/fed), indicating that these traits were predominantly controlled by the non-additive gene action. These results are in accordance with those obtained by San et al (2001), Mosa (2003), Ahmed (2013) and El-Ghonemy (2015) for plant height, Mosa (2010), Katta et al (2013) and El-Hosary (2014) for ear diameter and Attia et al (2015), Hassan (2015) and Wani et al (2017) for grain yield. For the exceptional trait, the ratio of GCA/GCA was equal unity, indicating that additive and non-additive type of gene action have the same importance in the performance of this trait.…”

“…The additive gene effects have been reported to be important in the genetic expression of maize grain yield (Badu-Apraku and Oyekunle, 2012;Abd El-Mottalb et al, 2013;Abo El-Haress, 2015;El-Hosary et al, 2018). However, other researchers reported that the non-additive genetic effects were represented the major role in the inheritance of maize grain yield and most of its components (Makumbi et al, 2011;Attia et al, 2015;Kamara, 2015;Wani et al, 2017). There is no agreement among the researchers on the type of gene action controlling maize yield or its related characters, and this due to differences in the genetic materials and the environments under which the experiments were performed.…”